| <!DOCTYPE html> |
| |
| <html lang="en"> |
| <head> |
| <meta charset="utf-8"/> |
| <meta content="IE=edge" http-equiv="X-UA-Compatible"/> |
| <meta content="width=device-width, initial-scale=1" name="viewport"/> |
| <meta content="Symbol and Automatic Differentiation" property="og:title"> |
| <meta content="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/og-logo.png" property="og:image"> |
| <meta content="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/og-logo.png" property="og:image:secure_url"> |
| <meta content="Symbol and Automatic Differentiation" property="og:description"/> |
| <title>Symbol and Automatic Differentiation — mxnet documentation</title> |
| <link crossorigin="anonymous" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" integrity="sha384-1q8mTJOASx8j1Au+a5WDVnPi2lkFfwwEAa8hDDdjZlpLegxhjVME1fgjWPGmkzs7" rel="stylesheet"/> |
| <link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.5.0/css/font-awesome.min.css" rel="stylesheet"/> |
| <link href="../../_static/basic.css" rel="stylesheet" type="text/css"> |
| <link href="../../_static/pygments.css" rel="stylesheet" type="text/css"> |
| <link href="../../_static/mxnet.css" rel="stylesheet" type="text/css"/> |
| <script type="text/javascript"> |
| var DOCUMENTATION_OPTIONS = { |
| URL_ROOT: '../../', |
| VERSION: '', |
| COLLAPSE_INDEX: false, |
| FILE_SUFFIX: '.html', |
| HAS_SOURCE: true, |
| SOURCELINK_SUFFIX: '.txt' |
| }; |
| </script> |
| <script src="https://code.jquery.com/jquery-1.11.1.min.js" type="text/javascript"></script> |
| <script src="../../_static/underscore.js" type="text/javascript"></script> |
| <script src="../../_static/searchtools_custom.js" type="text/javascript"></script> |
| <script src="../../_static/doctools.js" type="text/javascript"></script> |
| <script src="../../_static/selectlang.js" type="text/javascript"></script> |
| <script src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config=TeX-AMS-MML_HTMLorMML" type="text/javascript"></script> |
| <script type="text/javascript"> jQuery(function() { Search.loadIndex("/searchindex.js"); Search.init();}); </script> |
| <script> |
| (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ |
| (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new |
| Date();a=s.createElement(o), |
| m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) |
| })(window,document,'script','https://www.google-analytics.com/analytics.js','ga'); |
| |
| ga('create', 'UA-96378503-1', 'auto'); |
| ga('send', 'pageview'); |
| |
| </script> |
| <!-- --> |
| <!-- <script type="text/javascript" src="../../_static/jquery.js"></script> --> |
| <!-- --> |
| <!-- <script type="text/javascript" src="../../_static/underscore.js"></script> --> |
| <!-- --> |
| <!-- <script type="text/javascript" src="../../_static/doctools.js"></script> --> |
| <!-- --> |
| <!-- <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script> --> |
| <!-- --> |
| <link href="../../genindex.html" rel="index" title="Index"> |
| <link href="../../search.html" rel="search" title="Search"/> |
| <link href="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/mxnet-icon.png" rel="icon" type="image/png"/> |
| </link></link></link></meta></meta></meta></head> |
| <body background="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/mxnet-background-compressed.jpeg" role="document"> |
| <div class="content-block"><div class="navbar navbar-fixed-top"> |
| <div class="container" id="navContainer"> |
| <div class="innder" id="header-inner"> |
| <h1 id="logo-wrap"> |
| <a href="../../" id="logo"><img src="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/mxnet_logo.png"/></a> |
| </h1> |
| <nav class="nav-bar" id="main-nav"> |
| <a class="main-nav-link" href="../../install/index.html">Install</a> |
| <span id="dropdown-menu-position-anchor"> |
| <a aria-expanded="true" aria-haspopup="true" class="main-nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button">Gluon <span class="caret"></span></a> |
| <ul class="dropdown-menu navbar-menu" id="package-dropdown-menu"> |
| <li><a class="main-nav-link" href="../../gluon/index.html">About</a></li> |
| <li><a class="main-nav-link" href="http://gluon.mxnet.io">Tutorials</a></li> |
| </ul> |
| </span> |
| <span id="dropdown-menu-position-anchor"> |
| <a aria-expanded="true" aria-haspopup="true" class="main-nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button">API <span class="caret"></span></a> |
| <ul class="dropdown-menu navbar-menu" id="package-dropdown-menu"> |
| <li><a class="main-nav-link" href="../../api/python/index.html">Python</a></li> |
| <li><a class="main-nav-link" href="../../api/c++/index.html">C++</a></li> |
| <li><a class="main-nav-link" href="../../api/clojure/index.html">Clojure</a></li> |
| <li><a class="main-nav-link" href="../../api/julia/index.html">Julia</a></li> |
| <li><a class="main-nav-link" href="../../api/perl/index.html">Perl</a></li> |
| <li><a class="main-nav-link" href="../../api/r/index.html">R</a></li> |
| <li><a class="main-nav-link" href="../../api/scala/index.html">Scala</a></li> |
| </ul> |
| </span> |
| <span id="dropdown-menu-position-anchor-docs"> |
| <a aria-expanded="true" aria-haspopup="true" class="main-nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button">Docs <span class="caret"></span></a> |
| <ul class="dropdown-menu navbar-menu" id="package-dropdown-menu-docs"> |
| <li><a class="main-nav-link" href="../../faq/index.html">FAQ</a></li> |
| <li><a class="main-nav-link" href="../../tutorials/index.html">Tutorials</a> |
| <li><a class="main-nav-link" href="https://github.com/apache/incubator-mxnet/tree/master/example">Examples</a></li> |
| <li><a class="main-nav-link" href="../../architecture/index.html">Architecture</a></li> |
| <li><a class="main-nav-link" href="../../api/python/gluon/model_zoo.html">Model Zoo</a></li> |
| <li><a class="main-nav-link" href="../../api/python/contrib/onnx.html">ONNX</a></li> |
| </li></ul> |
| </span> |
| <span id="dropdown-menu-position-anchor-community"> |
| <a aria-expanded="true" aria-haspopup="true" class="main-nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button">Community <span class="caret"></span></a> |
| <ul class="dropdown-menu navbar-menu" id="package-dropdown-menu-community"> |
| <li><a class="main-nav-link" href="http://discuss.mxnet.io">Forum</a></li> |
| <li><a class="main-nav-link" href="https://github.com/apache/incubator-mxnet">Github</a></li> |
| <li><a class="main-nav-link" href="../../community/contribute.html">Contribute</a></li> |
| <li><a class="main-nav-link" href="../../community/ecosystem.html">Ecosystem</a></li> |
| <li><a class="main-nav-link" href="../../community/powered_by.html">Powered By</a></li> |
| </ul> |
| </span> |
| <span id="dropdown-menu-position-anchor-version" style="position: relative"><a href="#" class="main-nav-link dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="true">Versions(master)<span class="caret"></span></a><ul id="package-dropdown-menu" class="dropdown-menu"><li><a class="main-nav-link" href=http://mxnet.incubator.apache.org/>master</a></li><li><a class="main-nav-link" href=http://mxnet.incubator.apache.org/versions/1.2.1/index.html>1.2.1</a></li><li><a class="main-nav-link" href=http://mxnet.incubator.apache.org/versions/1.1.0/index.html>1.1.0</a></li><li><a class="main-nav-link" href=http://mxnet.incubator.apache.org/versions/1.0.0/index.html>1.0.0</a></li><li><a class="main-nav-link" href=http://mxnet.incubator.apache.org/versions/0.12.1/index.html>0.12.1</a></li><li><a class="main-nav-link" href=http://mxnet.incubator.apache.org/versions/0.11.0/index.html>0.11.0</a></li></ul></span></nav> |
| <script> function getRootPath(){ return "../../" } </script> |
| <div class="burgerIcon dropdown"> |
| <a class="dropdown-toggle" data-toggle="dropdown" href="#" role="button">☰</a> |
| <ul class="dropdown-menu" id="burgerMenu"> |
| <li><a href="../../install/index.html">Install</a></li> |
| <li><a class="main-nav-link" href="../../tutorials/index.html">Tutorials</a></li> |
| <li class="dropdown-submenu dropdown"> |
| <a aria-haspopup="true" class="dropdown-toggle burger-link" data-toggle="dropdown" href="#" role="button" tabindex="-1">Community</a> |
| <ul class="dropdown-menu"> |
| <li><a href="http://discuss.mxnet.io" tabindex="-1">Forum</a></li> |
| <li><a href="https://github.com/apache/incubator-mxnet" tabindex="-1">Github</a></li> |
| <li><a href="../../community/contribute.html" tabindex="-1">Contribute</a></li> |
| <li><a href="../../community/ecosystem.html" tabindex="-1">Ecosystem</a></li> |
| <li><a href="../../community/powered_by.html" tabindex="-1">Powered By</a></li> |
| </ul> |
| </li> |
| <li class="dropdown-submenu"> |
| <a aria-haspopup="true" class="dropdown-toggle burger-link" data-toggle="dropdown" href="#" role="button" tabindex="-1">API</a> |
| <ul class="dropdown-menu"> |
| <li><a href="../../api/python/index.html" tabindex="-1">Python</a> |
| </li> |
| <li><a href="../../api/c++/index.html" tabindex="-1">C++</a> |
| </li> |
| <li><a href="../../api/clojure/index.html" tabindex="-1">Clojure</a> |
| </li> |
| <li><a href="../../api/julia/index.html" tabindex="-1">Julia</a> |
| </li> |
| <li><a href="../../api/perl/index.html" tabindex="-1">Perl</a> |
| </li> |
| <li><a href="../../api/r/index.html" tabindex="-1">R</a> |
| </li> |
| <li><a href="../../api/scala/index.html" tabindex="-1">Scala</a> |
| </li> |
| </ul> |
| </li> |
| <li class="dropdown-submenu"> |
| <a aria-expanded="true" aria-haspopup="true" class="dropdown-toggle burger-link" data-toggle="dropdown" href="#" tabindex="-1">Docs</a> |
| <ul class="dropdown-menu"> |
| <li><a href="../../tutorials/index.html" tabindex="-1">Tutorials</a></li> |
| <li><a href="../../faq/index.html" tabindex="-1">FAQ</a></li> |
| <li><a href="../../architecture/index.html" tabindex="-1">Architecture</a></li> |
| <li><a href="https://github.com/apache/incubator-mxnet/tree/master/example" tabindex="-1">Examples</a></li> |
| <li><a href="../../api/python/gluon/model_zoo.html" tabindex="-1">Gluon Model Zoo</a></li> |
| </ul> |
| </li> |
| <li><a class="main-nav-link" href="https://github.com/dmlc/mxnet">Github</a></li> |
| <li id="dropdown-menu-position-anchor-version-mobile" class="dropdown-submenu" style="position: relative"><a href="#" tabindex="-1">Versions(master)</a><ul class="dropdown-menu"><li><a tabindex="-1" href=http://mxnet.incubator.apache.org/>master</a></li><li><a tabindex="-1" href=http://mxnet.incubator.apache.org/versions/1.2.1/index.html>1.2.1</a></li><li><a tabindex="-1" href=http://mxnet.incubator.apache.org/versions/1.1.0/index.html>1.1.0</a></li><li><a tabindex="-1" href=http://mxnet.incubator.apache.org/versions/1.0.0/index.html>1.0.0</a></li><li><a tabindex="-1" href=http://mxnet.incubator.apache.org/versions/0.12.1/index.html>0.12.1</a></li><li><a tabindex="-1" href=http://mxnet.incubator.apache.org/versions/0.11.0/index.html>0.11.0</a></li></ul></li></ul> |
| </div> |
| <div class="plusIcon dropdown"> |
| <a class="dropdown-toggle" data-toggle="dropdown" href="#" role="button"><span aria-hidden="true" class="glyphicon glyphicon-plus"></span></a> |
| <ul class="dropdown-menu dropdown-menu-right" id="plusMenu"></ul> |
| </div> |
| <div id="search-input-wrap"> |
| <form action="../../search.html" autocomplete="off" class="" method="get" role="search"> |
| <div class="form-group inner-addon left-addon"> |
| <i class="glyphicon glyphicon-search"></i> |
| <input class="form-control" name="q" placeholder="Search" type="text"/> |
| </div> |
| <input name="check_keywords" type="hidden" value="yes"> |
| <input name="area" type="hidden" value="default"/> |
| </input></form> |
| <div id="search-preview"></div> |
| </div> |
| <div id="searchIcon"> |
| <span aria-hidden="true" class="glyphicon glyphicon-search"></span> |
| </div> |
| <!-- <div id="lang-select-wrap"> --> |
| <!-- <label id="lang-select-label"> --> |
| <!-- <\!-- <i class="fa fa-globe"></i> -\-> --> |
| <!-- <span></span> --> |
| <!-- </label> --> |
| <!-- <select id="lang-select"> --> |
| <!-- <option value="en">Eng</option> --> |
| <!-- <option value="zh">中文</option> --> |
| <!-- </select> --> |
| <!-- </div> --> |
| <!-- <a id="mobile-nav-toggle"> |
| <span class="mobile-nav-toggle-bar"></span> |
| <span class="mobile-nav-toggle-bar"></span> |
| <span class="mobile-nav-toggle-bar"></span> |
| </a> --> |
| </div> |
| </div> |
| </div> |
| <script type="text/javascript"> |
| $('body').css('background', 'white'); |
| </script> |
| <div class="container"> |
| <div class="row"> |
| <div aria-label="main navigation" class="sphinxsidebar leftsidebar" role="navigation"> |
| <div class="sphinxsidebarwrapper"> |
| <ul> |
| <li class="toctree-l1"><a class="reference internal" href="../../api/python/index.html">Python Documents</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../api/r/index.html">R Documents</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../api/julia/index.html">Julia Documents</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../api/c++/index.html">C++ Documents</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../api/scala/index.html">Scala Documents</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../api/perl/index.html">Perl Documents</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../faq/index.html">HowTo Documents</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../architecture/index.html">System Documents</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../index.html">Tutorials</a></li> |
| <li class="toctree-l1"><a class="reference internal" href="../../community/contribute.html">Community</a></li> |
| </ul> |
| </div> |
| </div> |
| <div class="content"> |
| <div class="page-tracker"></div> |
| <div class="section" id="symbol-and-automatic-differentiation"> |
| <span id="symbol-and-automatic-differentiation"></span><h1>Symbol and Automatic Differentiation<a class="headerlink" href="#symbol-and-automatic-differentiation" title="Permalink to this headline">¶</a></h1> |
| <p>The computational unit <code class="docutils literal"><span class="pre">NDArray</span></code> requires a way to construct neural networks. MXNet provides a symbolic interface, named Symbol, to do this. Symbol combines both flexibility and efficiency.</p> |
| <div class="section" id="basic-composition-of-symbols"> |
| <span id="basic-composition-of-symbols"></span><h2>Basic Composition of Symbols<a class="headerlink" href="#basic-composition-of-symbols" title="Permalink to this headline">¶</a></h2> |
| <p>The following code creates a two-layer perceptron network:</p> |
| <div class="highlight-r"><div class="highlight"><pre><span></span><span class="kn">require</span><span class="p">(</span>mxnet<span class="p">)</span> |
| net <span class="o"><-</span> mx.symbol.Variable<span class="p">(</span><span class="s">"data"</span><span class="p">)</span> |
| net <span class="o"><-</span> mx.symbol.FullyConnected<span class="p">(</span>data<span class="o">=</span>net<span class="p">,</span> name<span class="o">=</span><span class="s">"fc1"</span><span class="p">,</span> num_hidden<span class="o">=</span><span class="m">128</span><span class="p">)</span> |
| net <span class="o"><-</span> mx.symbol.Activation<span class="p">(</span>data<span class="o">=</span>net<span class="p">,</span> name<span class="o">=</span><span class="s">"relu1"</span><span class="p">,</span> act_type<span class="o">=</span><span class="s">"relu"</span><span class="p">)</span> |
| net <span class="o"><-</span> mx.symbol.FullyConnected<span class="p">(</span>data<span class="o">=</span>net<span class="p">,</span> name<span class="o">=</span><span class="s">"fc2"</span><span class="p">,</span> num_hidden<span class="o">=</span><span class="m">64</span><span class="p">)</span> |
| net <span class="o"><-</span> mx.symbol.Softmax<span class="p">(</span>data<span class="o">=</span>net<span class="p">,</span> name<span class="o">=</span><span class="s">"out"</span><span class="p">)</span> |
| <span class="kp">class</span><span class="p">(</span>net<span class="p">)</span> |
| </pre></div> |
| </div> |
| <div class="highlight-default"><div class="highlight"><pre><span></span><span class="c1">## [1] "Rcpp_MXSymbol"</span> |
| <span class="c1">## attr(,"package")</span> |
| <span class="c1">## [1] "mxnet"</span> |
| </pre></div> |
| </div> |
| <p>Each symbol takes a (unique) string name. <em>Variable</em> often defines the inputs, |
| or free variables. Other symbols take a symbol as the input (<em>data</em>), |
| and may accept other hyper parameters, such as the number of hidden neurons (<em>num_hidden</em>) |
| or the activation type (<em>act_type</em>).</p> |
| <p>A symbol can be viewed as a function that takes several arguments, whose |
| names are automatically generated and can be retrieved with the following command:</p> |
| <div class="highlight-r"><div class="highlight"><pre><span></span>arguments<span class="p">(</span>net<span class="p">)</span> |
| </pre></div> |
| </div> |
| <div class="highlight-default"><div class="highlight"><pre><span></span><span class="c1">## [1] "data" "fc1_weight" "fc1_bias" "fc2_weight" "fc2_bias"</span> |
| <span class="c1">## [6] "out_label"</span> |
| </pre></div> |
| </div> |
| <p>The arguments are the parameters need by each symbol:</p> |
| <ul class="simple"> |
| <li><em>data</em>: Input data needed by the variable <em>data</em></li> |
| <li><em>fc1_weight</em> and <em>fc1_bias</em>: The weight and bias for the first fully connected layer, <em>fc1</em></li> |
| <li><em>fc2_weight</em> and <em>fc2_bias</em>: The weight and bias for the second fully connected layer, <em>fc2</em></li> |
| <li><em>out_label</em>: The label needed by the loss</li> |
| </ul> |
| <p>We can also specify the automatically generated names explicitly:</p> |
| <div class="highlight-r"><div class="highlight"><pre><span></span>data <span class="o"><-</span> mx.symbol.Variable<span class="p">(</span><span class="s">"data"</span><span class="p">)</span> |
| w <span class="o"><-</span> mx.symbol.Variable<span class="p">(</span><span class="s">"myweight"</span><span class="p">)</span> |
| net <span class="o"><-</span> mx.symbol.FullyConnected<span class="p">(</span>data<span class="o">=</span>data<span class="p">,</span> weight<span class="o">=</span>w<span class="p">,</span> name<span class="o">=</span><span class="s">"fc1"</span><span class="p">,</span> num_hidden<span class="o">=</span><span class="m">128</span><span class="p">)</span> |
| arguments<span class="p">(</span>net<span class="p">)</span> |
| </pre></div> |
| </div> |
| <div class="highlight-default"><div class="highlight"><pre><span></span><span class="c1">## [1] "data" "myweight" "fc1_bias"</span> |
| </pre></div> |
| </div> |
| </div> |
| <div class="section" id="more-complicated-composition-of-symbols"> |
| <span id="more-complicated-composition-of-symbols"></span><h2>More Complicated Composition of Symbols<a class="headerlink" href="#more-complicated-composition-of-symbols" title="Permalink to this headline">¶</a></h2> |
| <p>MXNet provides well-optimized symbols for |
| commonly used layers in deep learning. You can also define new operators |
| in Python. The following example first performs an element-wise add between two |
| symbols, then feeds them to the fully connected operator:</p> |
| <div class="highlight-r"><div class="highlight"><pre><span></span>lhs <span class="o"><-</span> mx.symbol.Variable<span class="p">(</span><span class="s">"data1"</span><span class="p">)</span> |
| rhs <span class="o"><-</span> mx.symbol.Variable<span class="p">(</span><span class="s">"data2"</span><span class="p">)</span> |
| net <span class="o"><-</span> mx.symbol.FullyConnected<span class="p">(</span>data<span class="o">=</span>lhs <span class="o">+</span> rhs<span class="p">,</span> name<span class="o">=</span><span class="s">"fc1"</span><span class="p">,</span> num_hidden<span class="o">=</span><span class="m">128</span><span class="p">)</span> |
| arguments<span class="p">(</span>net<span class="p">)</span> |
| </pre></div> |
| </div> |
| <div class="highlight-default"><div class="highlight"><pre><span></span><span class="c1">## [1] "data1" "data2" "fc1_weight" "fc1_bias"</span> |
| </pre></div> |
| </div> |
| <p>We can construct a symbol more flexibly than by using the single |
| forward composition, for example:</p> |
| <div class="highlight-r"><div class="highlight"><pre><span></span>net <span class="o"><-</span> mx.symbol.Variable<span class="p">(</span><span class="s">"data"</span><span class="p">)</span> |
| net <span class="o"><-</span> mx.symbol.FullyConnected<span class="p">(</span>data<span class="o">=</span>net<span class="p">,</span> name<span class="o">=</span><span class="s">"fc1"</span><span class="p">,</span> num_hidden<span class="o">=</span><span class="m">128</span><span class="p">)</span> |
| net2 <span class="o"><-</span> mx.symbol.Variable<span class="p">(</span><span class="s">"data2"</span><span class="p">)</span> |
| net2 <span class="o"><-</span> mx.symbol.FullyConnected<span class="p">(</span>data<span class="o">=</span>net2<span class="p">,</span> name<span class="o">=</span><span class="s">"net2"</span><span class="p">,</span> num_hidden<span class="o">=</span><span class="m">128</span><span class="p">)</span> |
| composed.net <span class="o"><-</span> mx.apply<span class="p">(</span>net<span class="p">,</span> data<span class="o">=</span>net2<span class="p">,</span> name<span class="o">=</span><span class="s">"compose"</span><span class="p">)</span> |
| arguments<span class="p">(</span>composed.net<span class="p">)</span> |
| </pre></div> |
| </div> |
| <div class="highlight-default"><div class="highlight"><pre><span></span><span class="c1">## [1] "data2" "net2_weight" "net2_bias" "fc1_weight" "fc1_bias"</span> |
| </pre></div> |
| </div> |
| <p>In the example, <em>net</em> is used as a function to apply to an existing symbol |
| <em>net</em>. The resulting <em>composed.net</em> will replace the original argument <em>data</em> with |
| <em>net2</em> instead.</p> |
| </div> |
| <div class="section" id="training-a-neural-net"> |
| <span id="training-a-neural-net"></span><h2>Training a Neural Net<a class="headerlink" href="#training-a-neural-net" title="Permalink to this headline">¶</a></h2> |
| <p>The <a class="reference external" href="https://github.com/apache/incubator-mxnet/blob/master/R-package/R/model.R">model API</a> is a thin wrapper around the symbolic executors to support neural net training.</p> |
| <p>We encourage you to read <a class="reference internal" href="../../api/python/symbol_in_pictures/symbol_in_pictures.html"><span class="doc">Symbolic Configuration and Execution in Pictures for python package</span></a>for a detailed explanation of concepts in pictures.</p> |
| </div> |
| <div class="section" id="how-efficient-is-the-symbolic-api"> |
| <span id="how-efficient-is-the-symbolic-api"></span><h2>How Efficient Is the Symbolic API?<a class="headerlink" href="#how-efficient-is-the-symbolic-api" title="Permalink to this headline">¶</a></h2> |
| <p>The Symbolic API brings the efficient C++ |
| operations in powerful toolkits, such as CXXNet and Caffe, together with the |
| flexible dynamic NDArray operations. All of the memory and computation resources are |
| allocated statically during bind operations, to maximize runtime performance and memory |
| utilization.</p> |
| <p>The coarse-grained operators are equivalent to CXXNet layers, which are |
| extremely efficient. We also provide fine-grained operators for more flexible |
| composition. Because MXNet does more in-place memory allocation, it can |
| be more memory efficient than CXXNet and gets to the same runtime with |
| greater flexibility.</p> |
| </div> |
| <div class="section" id="next-steps"> |
| <span id="next-steps"></span><h2>Next Steps<a class="headerlink" href="#next-steps" title="Permalink to this headline">¶</a></h2> |
| <div class="toctree-wrapper compound"> |
| <ul> |
| <li class="toctree-l1"><a class="reference external" href="https://mxnet.incubator.apache.org/tutorials/r/CallbackFunction.html">Write and use callback functions</a></li> |
| <li class="toctree-l1"><a class="reference external" href="https://mxnet.incubator.apache.org/tutorials/r/fiveMinutesNeuralNetwork.html">Neural Networks with MXNet in Five Minutes</a></li> |
| <li class="toctree-l1"><a class="reference external" href="https://mxnet.incubator.apache.org/tutorials/r/classifyRealImageWithPretrainedModel.html">Classify Real-World Images with Pre-trained Model</a></li> |
| <li class="toctree-l1"><a class="reference external" href="https://mxnet.incubator.apache.org/tutorials/r/mnistCompetition.html">Handwritten Digits Classification Competition</a></li> |
| <li class="toctree-l1"><a class="reference external" href="https://mxnet.incubator.apache.org/tutorials/r/charRnnModel.html">Character Language Model using RNN</a></li> |
| </ul> |
| </div> |
| </div> |
| </div> |
| </div> |
| </div> |
| <div aria-label="main navigation" class="sphinxsidebar rightsidebar" role="navigation"> |
| <div class="sphinxsidebarwrapper"> |
| <h3><a href="../../index.html">Table Of Contents</a></h3> |
| <ul> |
| <li><a class="reference internal" href="#">Symbol and Automatic Differentiation</a><ul> |
| <li><a class="reference internal" href="#basic-composition-of-symbols">Basic Composition of Symbols</a></li> |
| <li><a class="reference internal" href="#more-complicated-composition-of-symbols">More Complicated Composition of Symbols</a></li> |
| <li><a class="reference internal" href="#training-a-neural-net">Training a Neural Net</a></li> |
| <li><a class="reference internal" href="#how-efficient-is-the-symbolic-api">How Efficient Is the Symbolic API?</a></li> |
| <li><a class="reference internal" href="#next-steps">Next Steps</a></li> |
| </ul> |
| </li> |
| </ul> |
| </div> |
| </div> |
| </div><div class="footer"> |
| <div class="section-disclaimer"> |
| <div class="container"> |
| <div> |
| <img height="60" src="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/apache_incubator_logo.png"/> |
| <p> |
| Apache MXNet is an effort undergoing incubation at The Apache Software Foundation (ASF), <strong>sponsored by the <i>Apache Incubator</i></strong>. 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. |
| </p> |
| <p> |
| "Copyright © 2017-2018, The Apache Software Foundation |
| Apache MXNet, MXNet, Apache, the Apache feather, and the Apache MXNet project logo are either registered trademarks or trademarks of the Apache Software Foundation." |
| </p> |
| </div> |
| </div> |
| </div> |
| </div> <!-- pagename != index --> |
| </div> |
| <script crossorigin="anonymous" integrity="sha384-0mSbJDEHialfmuBBQP6A4Qrprq5OVfW37PRR3j5ELqxss1yVqOtnepnHVP9aJ7xS" src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script> |
| <script src="../../_static/js/sidebar.js" type="text/javascript"></script> |
| <script src="../../_static/js/search.js" type="text/javascript"></script> |
| <script src="../../_static/js/navbar.js" type="text/javascript"></script> |
| <script src="../../_static/js/clipboard.min.js" type="text/javascript"></script> |
| <script src="../../_static/js/copycode.js" type="text/javascript"></script> |
| <script src="../../_static/js/page.js" type="text/javascript"></script> |
| <script type="text/javascript"> |
| $('body').ready(function () { |
| $('body').css('visibility', 'visible'); |
| }); |
| </script> |
| </body> |
| </html> |