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page</button></div><div class="theme-doc-markdown markdown"><h1>Getting Started</h1> |
| <p>This article is a quick guide that explains how to work with GraphAr |
| C++. To begin with, please refer to the <a href="https://github.com/apache/incubator-graphar/blob/main/README.md#building-libraries" target="_blank" rel="noopener noreferrer">Building |
| Steps</a> |
| to install GraphAr.</p> |
| <h2 class="anchor anchorWithStickyNavbar_qibj" id="information-files">Information Files<a href="#information-files" class="hash-link" aria-label="Direct link to Information Files" title="Direct link to Information Files"></a></h2> |
| <p>GraphAr uses a group of Yaml files to save the meta information for a graph.</p> |
| <h3 class="anchor anchorWithStickyNavbar_qibj" id="graph-information">Graph information<a href="#graph-information" class="hash-link" aria-label="Direct link to Graph information" title="Direct link to Graph information"></a></h3> |
| <p>The graph information file defines the most basic information of a graph |
| includes its name, the root directory path of the data files, the vertex |
| information and edge information files it contains, and the version of |
| GraphAr. For example, the file "ldbc_sample.graph.yml" defines an |
| example graph named "ldbc_sample", which includes one type of vertices |
| ("person") and one type of edges ("person knows person").</p> |
| <div class="language-yaml codeBlockContainer_w3PW theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_Tt2Q"><pre tabindex="0" class="prism-code language-yaml codeBlock_xdHR thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_Sjn8"><span class="token-line" style="color:#393A34"><span class="token key atrule" style="color:#00a4db">name</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> ldbc_sample</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token key atrule" style="color:#00a4db">prefix</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> ./</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token key atrule" style="color:#00a4db">vertices</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">-</span><span class="token plain"> person.vertex.yml</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token key atrule" style="color:#00a4db">edges</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">-</span><span class="token plain"> person_knows_person.edge.yml</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token key atrule" style="color:#00a4db">version</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> gar/v1</span><br></span></code></pre><div class="buttonGroup_oM_0"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_CGtL" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_t3v4"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_srdl"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> |
| <h3 class="anchor anchorWithStickyNavbar_qibj" id="vertex-information">Vertex information<a href="#vertex-information" class="hash-link" aria-label="Direct link to Vertex information" title="Direct link to Vertex information"></a></h3> |
| <p>Each vertex information file defines a single group of vertices with the |
| same vertex label, e.g., "person" in this case. The vertex chunk size, |
| the relative path for vertex data files and the version of GraphAr are |
| specified. These vertices could have some properties, which are divided |
| into property groups. Each property group has its own file type (CSV, |
| ORC or Parquet) and the prefix of the relative path for its data files, |
| it also lists all properties in this group, with every property contains |
| the name, data type and if it is the primary key.</p> |
| <p>The file |
| <a href="https://github.com/apache/incubator-graphar-testing/blob/main/ldbc_sample/csv/person.vertex.yml" target="_blank" rel="noopener noreferrer">person.vertex.yml</a> |
| located inside the test data contains an example of the vertex |
| information file. In this example, the "person" vertices have two |
| property groups. The first group contains only one property (named "id") |
| and the second group contains three properties ("firstName", "lastName" |
| and "gender").</p> |
| <h3 class="anchor anchorWithStickyNavbar_qibj" id="edge-information">Edge information<a href="#edge-information" class="hash-link" aria-label="Direct link to Edge information" title="Direct link to Edge information"></a></h3> |
| <p>Each edge information file defines a single type of edges with specific |
| labels for the source vertex, destination vertex and the edge, e.g., |
| "person_knows_person" in this case. It defines the meta information such |
| as the edge chunk size, the source vertex chunk size, the destination |
| vertex chunk size, if the edges are directed or not, the relative file |
| path for edge data files, the adjLists and the version of GraphAr. The |
| file |
| <a href="https://github.com/apache/incubator-graphar-testing/blob/main/ldbc_sample/csv/person_knows_person.edge.yml" target="_blank" rel="noopener noreferrer">person_knows_person.edge.yml</a> |
| located inside the test data contains an example of the edge information |
| file.</p> |
| <p>In GraphAr format, separate data files are used to store the structure |
| (called adjList) and the properties for edges. The adjList type can be |
| either of <strong>unordered_by_source</strong>, <strong>unordered_by_dest</strong>, |
| <strong>ordered_by_source</strong> or <strong>ordered_by_dest</strong>. For a specific |
| type of adjList, the meta information includes its file path prefix, the |
| file type, as well as all the property groups attached.</p> |
| <div class="theme-admonition theme-admonition-note admonition_Q5_n alert alert--secondary"><div class="admonitionHeading_X17j"><span class="admonitionIcon_AlVM"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M6.3 5.69a.942.942 0 0 1-.28-.7c0-.28.09-.52.28-.7.19-.18.42-.28.7-.28.28 0 .52.09.7.28.18.19.28.42.28.7 0 .28-.09.52-.28.7a1 1 0 0 1-.7.3c-.28 0-.52-.11-.7-.3zM8 7.99c-.02-.25-.11-.48-.31-.69-.2-.19-.42-.3-.69-.31H6c-.27.02-.48.13-.69.31-.2.2-.3.44-.31.69h1v3c.02.27.11.5.31.69.2.2.42.31.69.31h1c.27 0 .48-.11.69-.31.2-.19.3-.42.31-.69H8V7.98v.01zM7 2.3c-3.14 0-5.7 2.54-5.7 5.68 0 3.14 2.56 5.7 5.7 5.7s5.7-2.55 5.7-5.7c0-3.15-2.56-5.69-5.7-5.69v.01zM7 .98c3.86 0 7 3.14 7 7s-3.14 7-7 7-7-3.12-7-7 3.14-7 7-7z"></path></svg></span>note</div><div class="admonitionContent_Z65i"><p>It is allowed to store different types of adjLists for a group of |
| edges at the same time.</p></div></div> |
| <h2 class="anchor anchorWithStickyNavbar_qibj" id="data-files">Data Files<a href="#data-files" class="hash-link" aria-label="Direct link to Data Files" title="Direct link to Data Files"></a></h2> |
| <h3 class="anchor anchorWithStickyNavbar_qibj" id="property-data">Property data<a href="#property-data" class="hash-link" aria-label="Direct link to Property data" title="Direct link to Property data"></a></h3> |
| <p>The vertex properties are stored in vertex property chunks with the |
| chunk size specified by the vertex information file. Different property |
| groups correspond to individual groups of data files. In our example, |
| the property group ("first name", "last name", "gender") for vertex |
| chunk 0 of "person" vertices are stored in |
| <a href="https://github.com/apache/incubator-graphar-testing/blob/main/ldbc_sample/csv/vertex/person/firstName_lastName_gender/chunk0" target="_blank" rel="noopener noreferrer">./vertex/person/firstName_lastName_gender/chunk0</a>.</p> |
| <p>In practice of graph processing, it is common to only query a subset of |
| columns of the properties. Thus, the column-oriented formats like Apache |
| ORC and Apache Parquet are more efficient, which eliminate the need to |
| read columns that are not relevant. We also provide data files in ORC |
| and Parquet for the example graph in the <a href="https://github.com/apache/incubator-graphar-testing/blob/main/ldbc_sample/" target="_blank" rel="noopener noreferrer">test |
| data</a>.</p> |
| <p>Similar with vertices, the edge properties are stored in edge property |
| chunks. For each vertex chunk, its associated edges (if the edge type is |
| <strong>ordered_by_source</strong> or <strong>unordered_by_source</strong>, the associated edges |
| are those in which the source vertex is in that chunk; otherwise, if the |
| edge type is <strong>ordered_by_dest</strong> or <strong>unordered_by_dest</strong>, the |
| associated edges are those in which the destination is in that chunk) |
| are maintained in some edge chunks, with the size of each chunk not |
| exceeding the edge chunk size specified in the edge information file.</p> |
| <p>For instance, the file |
| <a href="https://github.com/apache/incubator-graphar-testing/blob/main/ldbc_sample/csv/edge/person_knows_person/ordered_by_source/creationDate/part0/chunk0" target="_blank" rel="noopener noreferrer">./edge/person_knows_person/ordered_by_source/creationDate/part0/chunk0</a> |
| stores the property group "creationDate" of "person_knows_person" edges |
| for the first edge chunk of the first vertex chunk, and the adjList type |
| of the edges is <strong>ordered_by_source</strong>.</p> |
| <h3 class="anchor anchorWithStickyNavbar_qibj" id="adjlist-data">AdjList data<a href="#adjlist-data" class="hash-link" aria-label="Direct link to AdjList data" title="Direct link to AdjList data"></a></h3> |
| <p>The adjList in GraphAr describes the topology structure, i.e., the internal |
| id of the source vertex and the destination vertex for each of a group |
| of edges. As explained in <a href="https://graphar.apache.org/docs/specification/format#edge-chunks-in-graphar" target="_blank" rel="noopener noreferrer">Edges in GraphAr</a>, the edges are separated |
| into edge chunks, and each edge chunk has its own adjList table and 0 or |
| more property tables.</p> |
| <p>For example, the file |
| <a href="https://github.com/apache/incubator-graphar-testing/blob/main/ldbc_sample/csv/edge/person_knows_person/ordered_by_source/adj_list/part0/chunk0" target="_blank" rel="noopener noreferrer">./edge/person_knows_person/ordered_by_source/adj_list/part0/chunk0</a> |
| saves the adjList of "person_knows_person" edges for the first edge |
| chunk of the first vertex chunk, and the adjList type of the edges is |
| "ordered_by_source". This adjList table consists of only two columns: |
| one for the source and one for the destination; it can be saved in CSV, |
| ORC, or Parquet files.</p> |
| <div class="theme-admonition theme-admonition-note admonition_Q5_n alert alert--secondary"><div class="admonitionHeading_X17j"><span class="admonitionIcon_AlVM"><svg viewBox="0 0 14 16"><path fill-rule="evenodd" d="M6.3 5.69a.942.942 0 0 1-.28-.7c0-.28.09-.52.28-.7.19-.18.42-.28.7-.28.28 0 .52.09.7.28.18.19.28.42.28.7 0 .28-.09.52-.28.7a1 1 0 0 1-.7.3c-.28 0-.52-.11-.7-.3zM8 7.99c-.02-.25-.11-.48-.31-.69-.2-.19-.42-.3-.69-.31H6c-.27.02-.48.13-.69.31-.2.2-.3.44-.31.69h1v3c.02.27.11.5.31.69.2.2.42.31.69.31h1c.27 0 .48-.11.69-.31.2-.19.3-.42.31-.69H8V7.98v.01zM7 2.3c-3.14 0-5.7 2.54-5.7 5.68 0 3.14 2.56 5.7 5.7 5.7s5.7-2.55 5.7-5.7c0-3.15-2.56-5.69-5.7-5.69v.01zM7 .98c3.86 0 7 3.14 7 7s-3.14 7-7 7-7-3.12-7-7 3.14-7 7-7z"></path></svg></span>note</div><div class="admonitionContent_Z65i"><p>If the edges are ordered, there may also be offset chunks to construct |
| the index for accessing edges of a single vertex. These chunks will |
| tore the start offset of each vertex's edges, see |
| <a href="https://github.com/apache/incubator-graphar-testing/blob/main/ldbc_sample/csv/edge/person_knows_person/ordered_by_source/offset/chunk0" target="_blank" rel="noopener noreferrer">./edge/person_knows_person/ordered_by_source/offset/chunk0</a> |
| as an example.</p></div></div> |
| <h2 class="anchor anchorWithStickyNavbar_qibj" id="how-to-use-graphar">How to Use GraphAr<a href="#how-to-use-graphar" class="hash-link" aria-label="Direct link to How to Use GraphAr" title="Direct link to How to Use GraphAr"></a></h2> |
| <h3 class="anchor anchorWithStickyNavbar_qibj" id="construct-information">Construct information<a href="#construct-information" class="hash-link" aria-label="Direct link to Construct information" title="Direct link to Construct information"></a></h3> |
| <p>It is convenient to construct the graphar metadata and dump it to generate |
| information files. We provide an <a href="https://github.com/apache/incubator-graphar/blob/main/cpp/examples/construct_info_example.cc" target="_blank" rel="noopener noreferrer">example |
| program</a> |
| located in the source code which shows how to construct and dump the |
| files for graph information, vertex information and edge information.</p> |
| <p>Also, the metadata of a graph can be constructed easily through reading |
| the already existed information files, as the following code |
| illustrates:</p> |
| <div class="language-cpp codeBlockContainer_w3PW theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_Tt2Q"><pre tabindex="0" class="prism-code language-cpp codeBlock_xdHR thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_Sjn8"><span class="token-line" style="color:#393A34"><span class="token comment" style="color:#999988;font-style:italic">// construct graph information from file</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">std</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">string path </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// the path of the graph information file (e.g., ldbc_sample.graph.yml)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> graph_info </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> graphar</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token class-name">GraphInfo</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">Load</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">path</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">value</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token comment" style="color:#999988;font-style:italic">// get vertex information</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> vertex_info </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> graph_info</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">GetVertexInfo</span><span class="token punctuation" style="color:#393A34">(</span><span class="token string" style="color:#e3116c">"person"</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token keyword" style="color:#00009f">if</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">vertex_info </span><span class="token operator" style="color:#393A34">!=</span><span class="token plain"> </span><span class="token keyword" style="color:#00009f">nullptr</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// use vertex_info ...</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token punctuation" style="color:#393A34">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token comment" style="color:#999988;font-style:italic">// get edge information</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> edge_info </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> graph_info</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">GetEdgeInfo</span><span class="token punctuation" style="color:#393A34">(</span><span class="token string" style="color:#e3116c">"person"</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"knows"</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"person"</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token keyword" style="color:#00009f">if</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">edge_info </span><span class="token operator" style="color:#393A34">!=</span><span class="token plain"> </span><span class="token keyword" style="color:#00009f">nullptr</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// use edge_info ...</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token punctuation" style="color:#393A34">}</span><br></span></code></pre><div class="buttonGroup_oM_0"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_CGtL" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_t3v4"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_srdl"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> |
| <h3 class="anchor anchorWithStickyNavbar_qibj" id="read-graphar-format-files">Read GraphAr format files<a href="#read-graphar-format-files" class="hash-link" aria-label="Direct link to Read GraphAr format files" title="Direct link to Read GraphAr format files"></a></h3> |
| <p>GraphAr supports the flexible reading of graph data, e.g., allowing to read |
| data of a single vertex, a vertex chunk, or all vertices with a specific |
| label. In addition, necessary property groups can be selected to read |
| and avoid reading all properties from the files. Furthermore, GraphAr |
| provides convenient and flexible access to adjList, offset and property |
| chunks for edges.</p> |
| <p>As a simple case, the following example shows how to read all vertices |
| with label "person" of the graph defined by "graph_info" and output the |
| values of "id" and "firstName" for each vertex.</p> |
| <div class="language-cpp codeBlockContainer_w3PW theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_Tt2Q"><pre tabindex="0" class="prism-code language-cpp codeBlock_xdHR thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_Sjn8"><span class="token-line" style="color:#393A34"><span class="token plain">graph_info </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> vertices </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> graphar</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token class-name">VerticesCollection</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">Make</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">graph_info</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"person"</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">value</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token keyword" style="color:#00009f">for</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">(</span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> it </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> vertices</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">begin</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"> it </span><span class="token operator" style="color:#393A34">!=</span><span class="token plain"> vertices</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">end</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"> </span><span class="token operator" style="color:#393A34">++</span><span class="token plain">it</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// get a vertex and access its data</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> vertex </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> </span><span class="token operator" style="color:#393A34">*</span><span class="token plain">it</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">if</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">vertex</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">IsValid</span><span class="token punctuation" style="color:#393A34">(</span><span class="token string" style="color:#e3116c">"id"</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"> </span><span class="token operator" style="color:#393A34">&&</span><span class="token plain"> vertex</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">IsValid</span><span class="token punctuation" style="color:#393A34">(</span><span class="token string" style="color:#e3116c">"firstName"</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> std</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">cout </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"id="</span><span class="token plain"> </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> vertex</span><span class="token punctuation" style="color:#393A34">.</span><span class="token generic-function function" style="color:#d73a49">property</span><span class="token generic-function generic class-name operator" style="color:#393A34"><</span><span class="token generic-function generic class-name keyword" style="color:#00009f">int64_t</span><span class="token generic-function generic class-name operator" style="color:#393A34">></span><span class="token punctuation" style="color:#393A34">(</span><span class="token string" style="color:#e3116c">"id"</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">value</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"> </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">", firstName="</span><span class="token plain"> </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> vertex</span><span class="token punctuation" style="color:#393A34">.</span><span class="token generic-function function" style="color:#d73a49">property</span><span class="token generic-function generic class-name operator" style="color:#393A34"><</span><span class="token generic-function generic class-name">std</span><span class="token generic-function generic class-name double-colon punctuation" style="color:#393A34">::</span><span class="token generic-function generic class-name">string</span><span class="token generic-function generic class-name operator" style="color:#393A34">></span><span class="token punctuation" style="color:#393A34">(</span><span class="token string" style="color:#e3116c">"firstName"</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">value</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"> </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> std</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">endl</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token punctuation" style="color:#393A34">}</span><br></span></code></pre><div class="buttonGroup_oM_0"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_CGtL" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_t3v4"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_srdl"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> |
| <p>The next example reads all edges with label "person_knows_person" from |
| the above graph and outputs the end vertices for each edge.</p> |
| <div class="language-cpp codeBlockContainer_w3PW theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_Tt2Q"><pre tabindex="0" class="prism-code language-cpp codeBlock_xdHR thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_Sjn8"><span class="token-line" style="color:#393A34"><span class="token plain">graph_info </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> expect </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> graphar</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token class-name">EdgesCollection</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">Make</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">graph_info</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"person"</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"knows"</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"person"</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> graphar</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">AdjListType</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">ordered_by_source</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> edges </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> expect</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">value</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token keyword" style="color:#00009f">for</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">(</span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> it </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> edges</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">begin</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"> it </span><span class="token operator" style="color:#393A34">!=</span><span class="token plain"> edges</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">end</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"> </span><span class="token operator" style="color:#393A34">++</span><span class="token plain">it</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// get an edge and access its data</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> edge </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> </span><span class="token operator" style="color:#393A34">*</span><span class="token plain">it</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> std</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">cout </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"src="</span><span class="token plain"> </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> edge</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">source</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"> </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">", dst="</span><span class="token plain"> </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> edge</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">destination</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"> </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> std</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">endl</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token punctuation" style="color:#393A34">}</span><br></span></code></pre><div class="buttonGroup_oM_0"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_CGtL" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_t3v4"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_srdl"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> |
| <h3 class="anchor anchorWithStickyNavbar_qibj" id="write-graphar-format-files">Write GraphAr format files<a href="#write-graphar-format-files" class="hash-link" aria-label="Direct link to Write GraphAr format files" title="Direct link to Write GraphAr format files"></a></h3> |
| <p>As same with the readers, the GraphAr writers provide different-level |
| methods to output the graph data in memory into GraphAr format files.</p> |
| <p>As the simplest cases, the fist example below adds vertices to |
| <strong>VerticesBuilder</strong>, and then dumps the data to files; the second |
| example constructs a collection of edges and then dumps them.</p> |
| <div class="language-cpp codeBlockContainer_w3PW theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_Tt2Q"><pre tabindex="0" class="prism-code language-cpp codeBlock_xdHR thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_Sjn8"><span class="token-line" style="color:#393A34"><span class="token plain">vertex_info </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">prefix </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">graphar</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">builder</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">VerticesBuilder </span><span class="token function" style="color:#d73a49">builder</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">vertex_info</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> prefix</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token comment" style="color:#999988;font-style:italic">// add a vertex</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">graphar</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">builder</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">Vertex v</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">v</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">AddProperty</span><span class="token punctuation" style="color:#393A34">(</span><span class="token string" style="color:#e3116c">"id"</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> </span><span class="token number" style="color:#36acaa">933</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">v</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">AddProperty</span><span class="token punctuation" style="color:#393A34">(</span><span class="token string" style="color:#e3116c">"firstName"</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"Alice"</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">builder</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">AddVertex</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">v</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token comment" style="color:#999988;font-style:italic">// add other vertices</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token comment" style="color:#999988;font-style:italic">// ...</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token comment" style="color:#999988;font-style:italic">// write to GraphAr format files</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">builder</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">Dump</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><br></span></code></pre><div class="buttonGroup_oM_0"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_CGtL" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_t3v4"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_srdl"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> |
| <div class="language-cpp codeBlockContainer_w3PW theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_Tt2Q"><pre tabindex="0" class="prism-code language-cpp codeBlock_xdHR thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_Sjn8"><span class="token-line" style="color:#393A34"><span class="token plain">edge_info </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">prefix </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">vertices_num </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">graphar</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">builder</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">EdgesBuilder </span><span class="token function" style="color:#d73a49">builder</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">edge_info</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> prefix</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> graphar</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">AdjListType</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">ordered_by_source</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> vertices_num</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token comment" style="color:#999988;font-style:italic">// add an edge (0 -> 3)</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">graphar</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">builder</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">Edge </span><span class="token function" style="color:#d73a49">e</span><span class="token punctuation" style="color:#393A34">(</span><span class="token number" style="color:#36acaa">0</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> </span><span class="token number" style="color:#36acaa">3</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">e</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">AddProperty</span><span class="token punctuation" style="color:#393A34">(</span><span class="token string" style="color:#e3116c">"creationDate"</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"2011-07-20T20:02:04.233+0000"</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">builder</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">AddEdge</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">e</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token comment" style="color:#999988;font-style:italic">// add other edges</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token comment" style="color:#999988;font-style:italic">// ...</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token comment" style="color:#999988;font-style:italic">// write to GraphAr format files</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">builder</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">Dump</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><br></span></code></pre><div class="buttonGroup_oM_0"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_CGtL" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_t3v4"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_srdl"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> |
| <h3 class="anchor anchorWithStickyNavbar_qibj" id="a-pagerank-example">A PageRank Example<a href="#a-pagerank-example" class="hash-link" aria-label="Direct link to A PageRank Example" title="Direct link to A PageRank Example"></a></h3> |
| <p>Here we will go through an example of out-of-core graph analytic |
| algorithms based on GraphAr which calculates the PageRank. Please look |
| <a href="https://en.wikipedia.org/wiki/PageRank" target="_blank" rel="noopener noreferrer">here</a> if you want a detailed |
| explanation of the PageRank algorithm. And the source code can be found |
| at |
| <a href="https://github.com/apache/incubator-graphar/blob/main/cpp/examples/pagerank_example.cc" target="_blank" rel="noopener noreferrer">pagerank_example.cc</a>.</p> |
| <p>This program first reads in the graph information file to obtain the |
| metadata; then, it constructs the vertex and edge collections to enable |
| access to the graph. After that, an implementation of the PageRank |
| algorithm is provided, with data for the vertices stored in memory, and |
| the edges streamed through disk I/O. Finally, the vertex information |
| with type "person" is extended to include a new property named |
| "pagerank" (a new vertex information file named |
| <em>person-new-pagerank.vertex.yml</em> is saved) and the <strong>VerticesBuilder</strong> |
| is used to write the results to new generated data chunks.</p> |
| <p>Please refer to <a href="/docs/libraries/cpp/examples/out-of-core">more examples</a> to learn |
| about the other available case studies utilizing GraphAr.</p> |
| <h3 class="anchor anchorWithStickyNavbar_qibj" id="processing-graph-data-with-labels">Processing Graph Data with Labels<a href="#processing-graph-data-with-labels" class="hash-link" aria-label="Direct link to Processing Graph Data with Labels" title="Direct link to Processing Graph Data with Labels"></a></h3> |
| <p>As GraphAr supports LPG data, users can add labels for vertices and use related label filtering functions to obtain specified vertices. |
| The standard csv format of graph data with labels supported by GraphAr is <code>id|:LABEL|property_1|property_2</code>, if a vertex has multiple labels, use ; to separate them. Here is an example.</p> |
| <div class="language-csv codeBlockContainer_w3PW theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_Tt2Q"><pre tabindex="0" class="prism-code language-csv codeBlock_xdHR thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_Sjn8"><span class="token-line" style="color:#393A34"><span class="token plain">id|:LABEL|name|url</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">0|company;public|Kam_Air|http://dbpedia.org/resource/Kam_Air</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">1|company|Balkh_Airlines|http://dbpedia.org/resource/Balkh_Airlines</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">2|company|Khyber_Afghan_Airlines|http://dbpedia.org/resource/Khyber_Afghan_Airlines</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">...</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain">1575|university|Paktia_University|http://dbpedia.org/resource/Paktia_University</span><br></span></code></pre><div class="buttonGroup_oM_0"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_CGtL" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_t3v4"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_srdl"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> |
| <p>At the beginning, we need to add label information into the <code>yml</code> file of vertex. For this example, it should be as follows.</p> |
| <div class="language-yml codeBlockContainer_w3PW theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_Tt2Q"><pre tabindex="0" class="prism-code language-yml codeBlock_xdHR thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_Sjn8"><span class="token-line" style="color:#393A34"><span class="token comment" style="color:#999988;font-style:italic"># organisation.vertex.yml</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token key atrule" style="color:#00a4db">type</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> organisation</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token key atrule" style="color:#00a4db">chunk_size</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> </span><span class="token number" style="color:#36acaa">4096</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token key atrule" style="color:#00a4db">prefix</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> vertex/organisation/</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token comment" style="color:#999988;font-style:italic"># add the label infos</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token key atrule" style="color:#00a4db">labels</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">-</span><span class="token plain"> university</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">-</span><span class="token plain"> company</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">-</span><span class="token plain"> public</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token key atrule" style="color:#00a4db">property_groups</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">-</span><span class="token plain"> </span><span class="token key atrule" style="color:#00a4db">file_type</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> parquet</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token key atrule" style="color:#00a4db">properties</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">-</span><span class="token plain"> </span><span class="token key atrule" style="color:#00a4db">name</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> name</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token key atrule" style="color:#00a4db">data_type</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> string</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token key atrule" style="color:#00a4db">is_primary</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> </span><span class="token boolean important" style="color:#36acaa">false</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">-</span><span class="token plain"> </span><span class="token key atrule" style="color:#00a4db">name</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> url</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token key atrule" style="color:#00a4db">data_type</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> string</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token key atrule" style="color:#00a4db">is_primary</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> </span><span class="token boolean important" style="color:#36acaa">false</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">-</span><span class="token plain"> </span><span class="token key atrule" style="color:#00a4db">name</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> id</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token key atrule" style="color:#00a4db">data_type</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> int64</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token key atrule" style="color:#00a4db">is_primary</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> </span><span class="token boolean important" style="color:#36acaa">true</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"></span><span class="token key atrule" style="color:#00a4db">version</span><span class="token punctuation" style="color:#393A34">:</span><span class="token plain"> gar/v1</span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span></code></pre><div class="buttonGroup_oM_0"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_CGtL" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_t3v4"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_srdl"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> |
| <p>When you have the data ready, you can read the file into <code>arrow::Table</code> by using arrow I/O function.</p> |
| <div class="language-cpp codeBlockContainer_w3PW theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_Tt2Q"><pre tabindex="0" class="prism-code language-cpp codeBlock_xdHR thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_Sjn8"><span class="token-line" style="color:#393A34"><span class="token plain"> arrow</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">csv</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">ReadOptions read_options</span><span class="token punctuation" style="color:#393A34">{</span><span class="token punctuation" style="color:#393A34">}</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"> </span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> arrow</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">csv</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">ParseOptions parse_options</span><span class="token punctuation" style="color:#393A34">{</span><span class="token punctuation" style="color:#393A34">}</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"> </span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> arrow</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">csv</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">ConvertOptions convert_options</span><span class="token punctuation" style="color:#393A34">{</span><span class="token punctuation" style="color:#393A34">}</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> parse_options</span><span class="token punctuation" style="color:#393A34">.</span><span class="token plain">delimiter </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> </span><span class="token char">'|'</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"> </span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> input </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> arrow</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">io</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token class-name">ReadableFile</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">Open</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">test_data_dir </span><span class="token operator" style="color:#393A34">+</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"/ldbc/organisation_0_0.csv"</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> arrow</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">default_memory_pool</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">ValueOrDie</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> reader </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> arrow</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">csv</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token class-name">TableReader</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">Make</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> arrow</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">io</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">default_io_context</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> input</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> read_options</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> parse_options</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> convert_options</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">ValueOrDie</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> std</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">shared_ptr</span><span class="token operator" style="color:#393A34"><</span><span class="token plain">arrow</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">Table</span><span class="token operator" style="color:#393A34">></span><span class="token plain"> table</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> table </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> reader</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">Read</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">ValueOrDie</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><br></span></code></pre><div class="buttonGroup_oM_0"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_CGtL" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_t3v4"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" class="copyButtonSuccessIcon_srdl"><path fill="currentColor" d="M21,7L9,19L3.5,13.5L4.91,12.09L9,16.17L19.59,5.59L21,7Z"></path></svg></span></button></div></div></div> |
| <p>You can export label table to disk in parquet format, and read it back into memory in the following way.</p> |
| <div class="language-cpp codeBlockContainer_w3PW theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_Tt2Q"><pre tabindex="0" class="prism-code language-cpp codeBlock_xdHR thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_Sjn8"><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> options_parquet_builder </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> </span><span class="token class-name">WriterOptions</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">ParquetOptionBuilder</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> options_parquet_builder</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">compression</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">arrow</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">Compression</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">type</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">UNCOMPRESSED</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// write arrow table as parquet chunk</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> maybe_writer </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token class-name">VertexPropertyWriter</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">Make</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">vertex_info</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> test_data_dir </span><span class="token operator" style="color:#393A34">+</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"/ldbc/parquet/"</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> options_parquet_builder</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">build</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token function" style="color:#d73a49">REQUIRE</span><span class="token punctuation" style="color:#393A34">(</span><span class="token operator" style="color:#393A34">!</span><span class="token plain">maybe_writer</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">has_error</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> writer </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> maybe_writer</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">value</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token function" style="color:#d73a49">REQUIRE</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">writer</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">WriteTable</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">table</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> </span><span class="token number" style="color:#36acaa">0</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">ok</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token function" style="color:#d73a49">REQUIRE</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">writer</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">WriteVerticesNum</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">table</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">num_rows</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">ok</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// read parquet chunk as arrow table</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> maybe_reader </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token class-name">VertexPropertyArrowChunkReader</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">MakeForLabels</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">graph_info</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"organisation"</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> labels</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> SelectType</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">LABELS</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token function" style="color:#d73a49">assert</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">maybe_reader</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">status</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">ok</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> reader </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> maybe_reader</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">value</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token function" style="color:#d73a49">assert</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">reader</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">seek</span><span class="token punctuation" style="color:#393A34">(</span><span class="token number" style="color:#36acaa">0</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">ok</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token function" style="color:#d73a49">assert</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">reader</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">GetLabelChunk</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">status</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">ok</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token function" style="color:#d73a49">assert</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">reader</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">next_chunk</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">ok</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><br></span></code></pre><div class="buttonGroup_oM_0"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_CGtL" aria-hidden="true"><svg viewBox="0 0 24 24" 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| <h3 class="anchor anchorWithStickyNavbar_qibj" id="using-label-filtering-functions">Using Label Filtering Functions<a href="#using-label-filtering-functions" class="hash-link" aria-label="Direct link to Using Label Filtering Functions" title="Direct link to Using Label Filtering Functions"></a></h3> |
| <p>By calling the <code>graphar::VerticesCollection::verticesWithLabel</code> or <code>graphar::VerticesCollection::verticesWithMultipleLabels</code> API, we can specify a certain type of vertices on a certain graph, then filter out all vertices that match one or more labels. Here we introduce several examples of using label filtering.</p> |
| <div class="language-cpp codeBlockContainer_w3PW theme-code-block" style="--prism-color:#393A34;--prism-background-color:#f6f8fa"><div class="codeBlockContent_Tt2Q"><pre tabindex="0" class="prism-code language-cpp codeBlock_xdHR thin-scrollbar" style="color:#393A34;background-color:#f6f8fa"><code class="codeBlockLines_Sjn8"><span class="token-line" style="color:#393A34"><span class="token plain"> graph_info </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token punctuation" style="color:#393A34">.</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> vertex_info </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> graph_info</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">GetVertexInfo</span><span class="token punctuation" style="color:#393A34">(</span><span class="token string" style="color:#e3116c">"organisation"</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> labels </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> vertex_info</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">GetLabels</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// query vertices with a specific label</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> maybe_filter_vertices_collection </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> graphar</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token class-name">VerticesCollection</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">verticesWithLabel</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">std</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">string</span><span class="token punctuation" style="color:#393A34">(</span><span class="token string" style="color:#e3116c">"company"</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> graph_info</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> type</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token function" style="color:#d73a49">ASSERT</span><span class="token punctuation" style="color:#393A34">(</span><span class="token operator" style="color:#393A34">!</span><span class="token plain">maybe_filter_vertices_collection</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">has_error</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> filter_vertices </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> maybe_filter_vertices_collection</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">value</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// iterate vertices with label "company"</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">for</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">(</span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> it </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> filter_vertices</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">begin</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"> it </span><span class="token operator" style="color:#393A34">!=</span><span class="token plain"> filter_vertices</span><span class="token operator" style="color:#393A34">-></span><span class="token function" style="color:#d73a49">end</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token operator" style="color:#393A34">++</span><span class="token plain">it</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// get a node's all labels</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> label_result </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"> it</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">label</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> std</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">cout </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"id: "</span><span class="token plain"> </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> it</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">id</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"> </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">" "</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">if</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">(</span><span class="token operator" style="color:#393A34">!</span><span class="token plain">label_result</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">has_error</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">for</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">(</span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> label </span><span class="token operator" style="color:#393A34">:</span><span class="token plain"> label_result</span><span class="token punctuation" style="color:#393A34">.</span><span class="token function" style="color:#d73a49">value</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">)</span><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">{</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> std</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token plain">cout </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> label </span><span class="token operator" style="color:#393A34"><<</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">" "</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// ...</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token punctuation" style="color:#393A34">}</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// query vertices based on a query result</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> maybe_filter_vertices_collection </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> graphar</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token class-name">VerticesCollection</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">verticesWithLabel</span><span class="token punctuation" style="color:#393A34">(</span><span class="token plain">std</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">string</span><span class="token punctuation" style="color:#393A34">(</span><span class="token string" style="color:#e3116c">"public"</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> filter_vertices</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// query vertices with multi labels</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token keyword" style="color:#00009f">auto</span><span class="token plain"> maybe_filter_vertices_collection </span><span class="token operator" style="color:#393A34">=</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> graphar</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token class-name">VerticesCollection</span><span class="token double-colon punctuation" style="color:#393A34">::</span><span class="token function" style="color:#d73a49">verticesWithMultipleLabels</span><span class="token punctuation" style="color:#393A34">(</span><span class="token punctuation" style="color:#393A34">{</span><span class="token string" style="color:#e3116c">"company"</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> </span><span class="token string" style="color:#e3116c">"public"</span><span class="token punctuation" style="color:#393A34">}</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> graph_info</span><span class="token punctuation" style="color:#393A34">,</span><span class="token plain"> type</span><span class="token punctuation" style="color:#393A34">)</span><span class="token punctuation" style="color:#393A34">;</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><span class="token comment" style="color:#999988;font-style:italic">// ...</span><span class="token plain"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain" style="display:inline-block"></span><br></span><span class="token-line" style="color:#393A34"><span class="token plain"> </span><br></span></code></pre><div class="buttonGroup_oM_0"><button type="button" aria-label="Copy code to clipboard" title="Copy" class="clean-btn"><span class="copyButtonIcons_CGtL" aria-hidden="true"><svg viewBox="0 0 24 24" class="copyButtonIcon_t3v4"><path fill="currentColor" d="M19,21H8V7H19M19,5H8A2,2 0 0,0 6,7V21A2,2 0 0,0 8,23H19A2,2 0 0,0 21,21V7A2,2 0 0,0 19,5M16,1H4A2,2 0 0,0 2,3V17H4V3H16V1Z"></path></svg><svg viewBox="0 0 24 24" 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| <p>Notice that, if the first two queries are executed successively, the result is equivalent to the third query.</p> |
| <h3 class="anchor anchorWithStickyNavbar_qibj" id="working-with-cloud-storage-s3-oss">Working with Cloud Storage (S3, OSS)<a href="#working-with-cloud-storage-s3-oss" class="hash-link" aria-label="Direct link to Working with Cloud Storage (S3, OSS)" title="Direct link to Working with Cloud Storage (S3, OSS)"></a></h3> |
| <p>GraphAr supports reading and writing data from and to cloud storage, including |
| AWS S3 and Alibaba Cloud OSS.</p> |
| <p>To read data from cloud storage, you can specify the path of the data files |
| with URI schema, e.g., "s3://bucket-name/path/to/data" or "s3://[access-key<!-- -->:secret-key<!-- -->]@bucket-name/path/to/data".</p> |
| <p><a href="https://github.com/apache/incubator-graphar/blob/main/cpp/test/test_info.cc#L777-L792" target="_blank" rel="noopener noreferrer">Code example</a> demonstrates how to read data from S3.</p> |
| <p>Note that once you use cloud storage, you need to call <code>graphar::InitializeS3</code> to initialize S3 APIs before starting the work and call<code>graphar::FinalizeS3()</code> to shut down the APIs after the work finish.</p></div><footer class="theme-doc-footer docusaurus-mt-lg"><div class="theme-doc-footer-edit-meta-row row"><div class="col"><a href="https://github.com/apache/incubator-graphar/edit/main/docs/libraries/cpp/getting-started.md" target="_blank" rel="noopener noreferrer" class="theme-edit-this-page"><svg fill="currentColor" height="20" width="20" viewBox="0 0 40 40" class="iconEdit_z10d" aria-hidden="true"><g><path d="m34.5 11.7l-3 3.1-6.3-6.3 3.1-3q0.5-0.5 1.2-0.5t1.1 0.5l3.9 3.9q0.5 0.4 0.5 1.1t-0.5 1.2z m-29.5 17.1l18.4-18.5 6.3 6.3-18.4 18.4h-6.3v-6.2z"></path></g></svg>Edit this page</a></div><div class="col lastUpdated_lw5U"></div></div></footer></article><nav class="pagination-nav docusaurus-mt-lg" aria-label="Docs pages"><a class="pagination-nav__link 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class="table-of-contents__link toc-highlight">Data Files</a><ul><li><a href="#property-data" class="table-of-contents__link toc-highlight">Property data</a></li><li><a href="#adjlist-data" class="table-of-contents__link toc-highlight">AdjList data</a></li></ul></li><li><a href="#how-to-use-graphar" class="table-of-contents__link toc-highlight">How to Use GraphAr</a><ul><li><a href="#construct-information" class="table-of-contents__link toc-highlight">Construct information</a></li><li><a href="#read-graphar-format-files" class="table-of-contents__link toc-highlight">Read GraphAr format files</a></li><li><a href="#write-graphar-format-files" class="table-of-contents__link toc-highlight">Write GraphAr format files</a></li><li><a href="#a-pagerank-example" class="table-of-contents__link toc-highlight">A PageRank Example</a></li><li><a href="#processing-graph-data-with-labels" class="table-of-contents__link toc-highlight">Processing Graph Data with Labels</a></li><li><a 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| <p> |
| Apache GraphAr is an effort undergoing incubation at The Apache Software Foundation (ASF), sponsored by the Apache Incubator. Incubation is required of all newly accepted projects until a further review indicates that the infrastructure, communications, and decision making process have stabilized in a manner consistent with other successful ASF projects. While incubation status is not necessarily a reflection of the completeness or stability of the code, it does indicate that the project has yet to be fully endorsed by the ASF. |
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| Copyright © 2026 The Apache Software Foundation, Licensed under the Apache License, Version 2.0. <br> |
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