| <!DOCTYPE html> |
| |
| <!--- |
| Licensed to the Apache Software Foundation (ASF) under one |
| or more contributor license agreements. See the NOTICE file |
| distributed with this work for additional information |
| regarding copyright ownership. The ASF licenses this file |
| to you under the Apache License, Version 2.0 (the |
| "License"); you may not use this file except in compliance |
| with the License. You may obtain a copy of the License at |
| http://www.apache.org/licenses/LICENSE-2.0 |
| Unless required by applicable law or agreed to in writing, |
| software distributed under the License is distributed on an |
| "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| KIND, either express or implied. See the License for the |
| specific language governing permissions and limitations |
| under the License. |
| --> |
| |
| <html lang=" en"><head> |
| <meta charset="utf-8"> |
| <meta http-equiv="X-UA-Compatible" content="IE=edge"> |
| <meta name="viewport" content="width=device-width, initial-scale=1"> |
| <link href="/versions/1.9.1/assets/img/mxnet-icon.png" rel="icon" type="image/png"><!-- Begin Jekyll SEO tag v2.6.1 --> |
| <title>NDArray | Apache MXNet</title> |
| <meta name="generator" content="Jekyll v3.8.6" /> |
| <meta property="og:title" content="NDArray" /> |
| <meta property="og:locale" content="en_US" /> |
| <meta name="description" content="A flexible and efficient library for deep learning." /> |
| <meta property="og:description" content="A flexible and efficient library for deep learning." /> |
| <link rel="canonical" href="https://mxnet.apache.org/versions/1.9.1/api/scala/docs/tutorials/ndarray" /> |
| <meta property="og:url" content="https://mxnet.apache.org/versions/1.9.1/api/scala/docs/tutorials/ndarray" /> |
| <meta property="og:site_name" content="Apache MXNet" /> |
| <script type="application/ld+json"> |
| {"description":"A flexible and efficient library for deep learning.","headline":"NDArray","@type":"WebPage","url":"https://mxnet.apache.org/versions/1.9.1/api/scala/docs/tutorials/ndarray","@context":"https://schema.org"}</script> |
| <!-- End Jekyll SEO tag --> |
| <link rel="stylesheet" href="/versions/1.9.1/assets/docsearch.min.css" /><link rel="stylesheet" href="/versions/1.9.1/assets/main.css"><link type="application/atom+xml" rel="alternate" href="https://mxnet.apache.org/versions/1.9.1/feed.xml" title="Apache MXNet" /><!-- Matomo --> |
| <script> |
| var _paq = window._paq = window._paq || []; |
| /* tracker methods like "setCustomDimension" should be called before "trackPageView" */ |
| /* We explicitly disable cookie tracking to avoid privacy issues */ |
| _paq.push(['disableCookies']); |
| _paq.push(['trackPageView']); |
| _paq.push(['enableLinkTracking']); |
| (function() { |
| var u="https://analytics.apache.org/"; |
| _paq.push(['setTrackerUrl', u+'matomo.php']); |
| _paq.push(['setSiteId', '23']); |
| var d=document, g=d.createElement('script'), s=d.getElementsByTagName('script')[0]; |
| g.async=true; g.src=u+'matomo.js'; s.parentNode.insertBefore(g,s); |
| })(); |
| </script> |
| <!-- End Matomo Code --> |
| |
| <script src="/versions/1.9.1/assets/js/jquery-3.3.1.min.js"></script> |
| <script src="/versions/1.9.1/assets/js/docsearch.min.js"></script><script src="/versions/1.9.1/assets/js/globalSearch.js" defer></script> |
| <script src="/versions/1.9.1/assets/js/clipboard.js" defer></script> |
| <script src="/versions/1.9.1/assets/js/copycode.js" defer></script></head> |
| <body><header class="site-header" role="banner"> |
| |
| <script> |
| $(document).ready(function () { |
| |
| // HEADER OPACITY LOGIC |
| |
| function opacity_header() { |
| var value = "rgba(4,140,204," + ($(window).scrollTop() / 300 + 0.4) + ")" |
| $('.site-header').css("background-color", value) |
| } |
| |
| $(window).scroll(function () { |
| opacity_header() |
| }) |
| opacity_header(); |
| |
| // MENU SELECTOR LOGIC |
| $('.page-link').each( function () { |
| if (window.location.href.includes(this.href)) { |
| $(this).addClass("page-current"); |
| } |
| }); |
| }) |
| </script> |
| <div class="wrapper"> |
| <a class="site-title" rel="author" href="/versions/1.9.1/"><img |
| src="/versions/1.9.1/assets/img/mxnet_logo.png" class="site-header-logo"></a> |
| <nav class="site-nav"> |
| <input type="checkbox" id="nav-trigger" class="nav-trigger"/> |
| <label for="nav-trigger"> |
| <span class="menu-icon"> |
| <svg viewBox="0 0 18 15" width="18px" height="15px"> |
| <path d="M18,1.484c0,0.82-0.665,1.484-1.484,1.484H1.484C0.665,2.969,0,2.304,0,1.484l0,0C0,0.665,0.665,0,1.484,0 h15.032C17.335,0,18,0.665,18,1.484L18,1.484z M18,7.516C18,8.335,17.335,9,16.516,9H1.484C0.665,9,0,8.335,0,7.516l0,0 c0-0.82,0.665-1.484,1.484-1.484h15.032C17.335,6.031,18,6.696,18,7.516L18,7.516z M18,13.516C18,14.335,17.335,15,16.516,15H1.484 C0.665,15,0,14.335,0,13.516l0,0c0-0.82,0.665-1.483,1.484-1.483h15.032C17.335,12.031,18,12.695,18,13.516L18,13.516z"/> |
| </svg> |
| </span> |
| </label> |
| <div class="gs-search-border"> |
| <div id="gs-search-icon"></div> |
| <form id="global-search-form"> |
| <input id="global-search" type="text" title="Search" placeholder="Search" /> |
| <div id="global-search-dropdown-container"> |
| <button class="gs-current-version btn" type="button" data-toggle="dropdown"> |
| <span id="gs-current-version-label">1.9.1</span> |
| <svg class="gs-dropdown-caret" viewBox="0 0 32 32" class="icon icon-caret-bottom" aria-hidden="true"> |
| <path class="dropdown-caret-path" d="M24 11.305l-7.997 11.39L8 11.305z"></path> |
| </svg> |
| </button> |
| <ul class="gs-opt-group gs-version-dropdown"> |
| |
| |
| <li class="gs-opt gs-versions">master</li> |
| |
| |
| |
| <li class="gs-opt gs-versions active">1.9.1</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.8.0</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.7.0</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.6.0</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.5.0</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.4.1</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.3.1</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.2.1</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.1.0</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.0.0</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">0.12.1</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">0.11.0</li> |
| |
| |
| </ul> |
| </div> |
| <span id="global-search-close">x</span> |
| </form> |
| </div> |
| <div class="trigger"> |
| <div id="global-search-mobile-border"> |
| <div id="gs-search-icon-mobile"></div> |
| <input id="global-search-mobile" placeholder="Search..." type="text"/> |
| <div id="global-search-dropdown-container-mobile"> |
| <button class="gs-current-version-mobile btn" type="button" data-toggle="dropdown"> |
| <svg class="gs-dropdown-caret" viewBox="0 0 32 32" class="icon icon-caret-bottom" aria-hidden="true"> |
| <path class="dropdown-caret-path" d="M24 11.305l-7.997 11.39L8 11.305z"></path> |
| </svg> |
| </button> |
| <ul class="gs-opt-group gs-version-dropdown-mobile"> |
| |
| |
| <li class="gs-opt gs-versions">master</li> |
| |
| |
| |
| <li class="gs-opt gs-versions active">1.9.1</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.8.0</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.7.0</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.6.0</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.5.0</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.4.1</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.3.1</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.2.1</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.1.0</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">1.0.0</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">0.12.1</li> |
| |
| |
| |
| <li class="gs-opt gs-versions">0.11.0</li> |
| |
| |
| </ul> |
| </div> |
| </div> |
| <a class="page-link" href="/versions/1.9.1/get_started">Get Started</a> |
| <a class="page-link" href="/versions/1.9.1/features">Features</a> |
| <a class="page-link" href="/versions/1.9.1/ecosystem">Ecosystem</a> |
| <a class="page-link" href="/versions/1.9.1/api">Docs & Tutorials</a> |
| <a class="page-link" href="/versions/1.9.1/trusted_by">Trusted By</a> |
| <a class="page-link" href="https://github.com/apache/mxnet">GitHub</a> |
| <div class="dropdown" style="min-width:100px"> |
| <span class="dropdown-header">Apache |
| <svg class="dropdown-caret" viewBox="0 0 32 32" class="icon icon-caret-bottom" aria-hidden="true"><path class="dropdown-caret-path" d="M24 11.305l-7.997 11.39L8 11.305z"></path></svg> |
| </span> |
| <div class="dropdown-content" style="min-width:250px"> |
| <a href="https://www.apache.org/foundation/">Apache Software Foundation</a> |
| <a href="https://www.apache.org/licenses/">License</a> |
| <a href="/versions/1.9.1/api/faq/security.html">Security</a> |
| <a href="https://privacy.apache.org/policies/privacy-policy-public.html">Privacy</a> |
| <a href="https://www.apache.org/events/current-event">Events</a> |
| <a href="https://www.apache.org/foundation/sponsorship.html">Sponsorship</a> |
| <a href="https://www.apache.org/foundation/thanks.html">Thanks</a> |
| </div> |
| </div> |
| <div class="dropdown"> |
| <span class="dropdown-header">1.9.1 |
| <svg class="dropdown-caret" viewBox="0 0 32 32" class="icon icon-caret-bottom" aria-hidden="true"><path class="dropdown-caret-path" d="M24 11.305l-7.997 11.39L8 11.305z"></path></svg> |
| </span> |
| <div class="dropdown-content"> |
| <a href="/">master</a> |
| <a class="dropdown-option-active" href="/versions/1.9.1/">1.9.1</a> |
| <a href="/versions/1.8.0/">1.8.0</a> |
| <a href="/versions/1.7.0/">1.7.0</a> |
| <a href="/versions/1.6.0/">1.6.0</a> |
| <a href="/versions/1.5.0/">1.5.0</a> |
| <a href="/versions/1.4.1/">1.4.1</a> |
| <a href="/versions/1.3.1/">1.3.1</a> |
| <a href="/versions/1.2.1/">1.2.1</a> |
| <a href="/versions/1.1.0/">1.1.0</a> |
| <a href="/versions/1.0.0/">1.0.0</a> |
| <a href="/versions/0.12.1/">0.12.1</a> |
| <a href="/versions/0.11.0/">0.11.0</a> |
| </div> |
| </div> |
| </div> |
| </nav> |
| </div> |
| </header> |
| <main class="page-content" aria-label="Content"> |
| <script> |
| |
| </script> |
| <article class="post"> |
| |
| <header class="post-header wrapper"> |
| <h1 class="post-title">NDArray</h1> |
| <h3></h3></header> |
| |
| <div class="post-content"> |
| <div class="wrapper"> |
| <div class="row"> |
| <div class="col-3 docs-side-bar"> |
| |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| |
| |
| |
| |
| |
| <div class="docs-card docs-side"> |
| <ul> |
| <div class="docs-action-btn"> |
| <a href="/versions/1.9.1/api/scala.html"> <img src="/versions/1.9.1/assets/img/compass.svg" |
| class="docs-logo-docs">Scala Guide <span |
| class="span-accented">›</span></a> |
| </div> |
| <div class="docs-action-btn"> |
| <a href="/versions/1.9.1/api/scala/docs/tutorials"> <img |
| src="/versions/1.9.1/assets/img/video-tutorial.svg" class="docs-logo-docs">Scala |
| Tutorials <span class="span-accented">›</span></a> |
| </div> |
| <div class="docs-action-btn"> |
| <a href="/versions/1.9.1/api/scala/docs/api"> <img src="/versions/1.9.1/assets/img/api.svg" |
| class="docs-logo-docs">Scala API Reference |
| <span class="span-accented">›</span></a> |
| </div> |
| |
| <!-- Let's show the list of tutorials --> |
| <br> |
| |
| <h3>Tutorials</h3> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| |
| <li><a href="/versions/1.9.1/api/scala/docs/tutorials/char_lstm">Char-LSTM</a></li> |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| |
| |
| <li><a href="/versions/1.9.1/api/scala/docs/tutorials/infer">Infer API</a></li> |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| |
| <li><a href="/versions/1.9.1/api/scala/docs/tutorials/io">Data Loading API</a></li> |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| |
| <li><a href="/versions/1.9.1/api/scala/docs/tutorials/kvstore">KVStore API</a></li> |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| |
| |
| <li><a href="/versions/1.9.1/api/scala/docs/tutorials/mnist">MNIST Example</a></li> |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| |
| <li><a href="/versions/1.9.1/api/scala/docs/tutorials/model">Model API *Deprecated*</a></li> |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| |
| <li><a href="/versions/1.9.1/api/scala/docs/tutorials/module">Module API</a></li> |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| |
| <li><a href="/versions/1.9.1/api/scala/docs/tutorials/mxnet_scala_on_intellij">Scala on IntelliJ</a></li> |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| |
| <li><a href="/versions/1.9.1/api/scala/docs/tutorials/ndarray">NDArray</a></li> |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| |
| <li><a href="/versions/1.9.1/api/scala/docs/tutorials/symbol">Symbol API</a></li> |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| |
| <li><a href="/versions/1.9.1/api/scala/docs/tutorials/symbol_in_pictures">Symbol in Pictures</a></li> |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| |
| <!-- page-category --> |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| <!-- page --> |
| |
| </ul> |
| </div> |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| |
| <!-- resource-p --> |
| <!-- page --> |
| </ul> |
| </div> |
| <div class="col-9"> |
| <!--- Licensed to the Apache Software Foundation (ASF) under one --> |
| |
| <!--- or more contributor license agreements. See the NOTICE file --> |
| |
| <!--- distributed with this work for additional information --> |
| |
| <!--- regarding copyright ownership. The ASF licenses this file --> |
| |
| <!--- to you under the Apache License, Version 2.0 (the --> |
| |
| <!--- "License"); you may not use this file except in compliance --> |
| |
| <!--- with the License. You may obtain a copy of the License at --> |
| |
| <!--- http://www.apache.org/licenses/LICENSE-2.0 --> |
| |
| <!--- Unless required by applicable law or agreed to in writing, --> |
| |
| <!--- software distributed under the License is distributed on an --> |
| |
| <!--- "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY --> |
| |
| <!--- KIND, either express or implied. See the License for the --> |
| |
| <!--- specific language governing permissions and limitations --> |
| |
| <!--- under the License. --> |
| |
| <h1 id="ndarray-api">NDArray API</h1> |
| |
| <p>The NDArray package (<code>mxnet.ndarray</code>) contains tensor operations similar to <code>numpy.ndarray</code>. The syntax is also similar, except for some additional calls for dealing with I/O and multiple devices.</p> |
| |
| <p>Topics:</p> |
| |
| <ul> |
| <li><a href="#create-ndarray">Create NDArray</a></li> |
| <li><a href="#ndarray-operations">NDArray Operations</a></li> |
| <li><a href="/versions/1.9.1/api/scala/docs/api/#org.apache.mxnet.NDArray">NDArray API Reference</a></li> |
| </ul> |
| |
| <h2 id="create-ndarray">Create NDArray</h2> |
| |
| <p>Create <code>mxnet.ndarray</code> as follows:</p> |
| <div class="highlight"><pre><code class="language-scala" data-lang="scala"><span class="k">import</span> <span class="nn">org.apache.mxnet._</span> |
| <span class="c1">// all-zero array of dimension 100x50 |
| </span><span class="k">val</span> <span class="nv">a</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">zeros</span><span class="o">(</span><span class="mi">100</span><span class="o">,</span> <span class="mi">50</span><span class="o">)</span> |
| <span class="c1">// all-one array of dimension 256x32x128x1 |
| </span><span class="k">val</span> <span class="nv">b</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">ones</span><span class="o">(</span><span class="mi">256</span><span class="o">,</span> <span class="mi">32</span><span class="o">,</span> <span class="mi">128</span><span class="o">,</span> <span class="mi">1</span><span class="o">)</span> |
| <span class="c1">// initialize array with contents, you can specify dimensions of array using Shape parameter while creating array. |
| </span><span class="k">val</span> <span class="nv">c</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">array</span><span class="o">(</span><span class="nc">Array</span><span class="o">(</span><span class="mi">1</span><span class="o">,</span> <span class="mi">2</span><span class="o">,</span> <span class="mi">3</span><span class="o">,</span> <span class="mi">4</span><span class="o">,</span> <span class="mi">5</span><span class="o">,</span> <span class="mi">6</span><span class="o">),</span> <span class="n">shape</span> <span class="k">=</span> <span class="nc">Shape</span><span class="o">(</span><span class="mi">2</span><span class="o">,</span> <span class="mi">3</span><span class="o">))</span> |
| </code></pre></div> |
| <p>This is similar to the way you use <code>numpy</code>.</p> |
| |
| <h2 id="ndarray-operations">NDArray Operations</h2> |
| |
| <p>We provide some basic ndarray operations, like arithmetic and slice operations.</p> |
| |
| <h3 id="arithmetic-operations">Arithmetic Operations</h3> |
| <div class="highlight"><pre><code class="language-scala" data-lang="scala"><span class="k">import</span> <span class="nn">org.apache.mxnet._</span> |
| <span class="k">val</span> <span class="nv">a</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">zeros</span><span class="o">(</span><span class="mi">100</span><span class="o">,</span> <span class="mi">50</span><span class="o">)</span> |
| <span class="nv">a</span><span class="o">.</span><span class="py">shape</span> |
| <span class="c1">// org.apache.mxnet.Shape = (100,50) |
| </span><span class="k">val</span> <span class="nv">b</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">ones</span><span class="o">(</span><span class="mi">100</span><span class="o">,</span> <span class="mi">50</span><span class="o">)</span> |
| <span class="c1">// c and d will be calculated in parallel here! |
| </span><span class="k">val</span> <span class="nv">c</span> <span class="k">=</span> <span class="n">a</span> <span class="o">+</span> <span class="n">b</span> |
| <span class="k">val</span> <span class="nv">d</span> <span class="k">=</span> <span class="n">a</span> <span class="o">-</span> <span class="n">b</span> |
| <span class="c1">// inplace operation, b's contents will be modified, but c and d won't be affected. |
| </span><span class="n">b</span> <span class="o">+=</span> <span class="n">d</span> |
| </code></pre></div> |
| <h3 id="multiplication-division-operations">Multiplication/Division Operations</h3> |
| <div class="highlight"><pre><code class="language-scala" data-lang="scala"><span class="k">import</span> <span class="nn">org.apache.mxnet._</span> |
| <span class="c1">// Multiplication |
| </span><span class="k">val</span> <span class="nv">ndones</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">ones</span><span class="o">(</span><span class="mi">2</span><span class="o">,</span> <span class="mi">1</span><span class="o">)</span> |
| <span class="k">val</span> <span class="nv">ndtwos</span> <span class="k">=</span> <span class="n">ndones</span> <span class="o">*</span> <span class="mi">2</span> |
| <span class="nv">ndtwos</span><span class="o">.</span><span class="py">toArray</span> |
| <span class="c1">// Array[Float] = Array(2.0, 2.0) |
| </span><span class="o">(</span><span class="n">ndones</span> <span class="o">*</span> <span class="n">ndones</span><span class="o">).</span><span class="py">toArray</span> |
| <span class="c1">// Array[Float] = Array(1.0, 1.0) |
| </span><span class="o">(</span><span class="n">ndtwos</span> <span class="o">*</span> <span class="n">ndtwos</span><span class="o">).</span><span class="py">toArray</span> |
| <span class="c1">// Array[Float] = Array(4.0, 4.0) |
| </span><span class="n">ndtwos</span> <span class="o">*=</span> <span class="n">ndtwos</span> <span class="c1">// inplace |
| </span><span class="nv">ndtwos</span><span class="o">.</span><span class="py">toArray</span> |
| <span class="c1">// Array[Float] = Array(4.0, 4.0) |
| </span> |
| <span class="c1">//Division |
| </span><span class="k">val</span> <span class="nv">ndones</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">ones</span><span class="o">(</span><span class="mi">2</span><span class="o">,</span> <span class="mi">1</span><span class="o">)</span> |
| <span class="k">val</span> <span class="nv">ndzeros</span> <span class="k">=</span> <span class="n">ndones</span> <span class="o">-</span> <span class="mf">1f</span> |
| <span class="k">val</span> <span class="nv">ndhalves</span> <span class="k">=</span> <span class="n">ndones</span> <span class="o">/</span> <span class="mi">2</span> |
| <span class="nv">ndhalves</span><span class="o">.</span><span class="py">toArray</span> |
| <span class="c1">// Array[Float] = Array(0.5, 0.5) |
| </span><span class="o">(</span><span class="n">ndhalves</span> <span class="o">/</span> <span class="n">ndhalves</span><span class="o">).</span><span class="py">toArray</span> |
| <span class="c1">// Array[Float] = Array(1.0, 1.0) |
| </span><span class="o">(</span><span class="n">ndones</span> <span class="o">/</span> <span class="n">ndones</span><span class="o">).</span><span class="py">toArray</span> |
| <span class="c1">// Array[Float] = Array(1.0, 1.0) |
| </span><span class="o">(</span><span class="n">ndzeros</span> <span class="o">/</span> <span class="n">ndones</span><span class="o">).</span><span class="py">toArray</span> |
| <span class="c1">// Array[Float] = Array(0.0, 0.0) |
| </span><span class="n">ndhalves</span> <span class="o">/=</span> <span class="n">ndhalves</span> |
| <span class="nv">ndhalves</span><span class="o">.</span><span class="py">toArray</span> |
| <span class="c1">// Array[Float] = Array(1.0, 1.0) |
| </span></code></pre></div> |
| <h3 id="slice-operations">Slice Operations</h3> |
| <div class="highlight"><pre><code class="language-scala" data-lang="scala"><span class="k">import</span> <span class="nn">org.apache.mxnet._</span> |
| <span class="k">val</span> <span class="nv">a</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">array</span><span class="o">(</span><span class="nc">Array</span><span class="o">(</span><span class="mf">1f</span><span class="o">,</span> <span class="mf">2f</span><span class="o">,</span> <span class="mf">3f</span><span class="o">,</span> <span class="mf">4f</span><span class="o">,</span> <span class="mf">5f</span><span class="o">,</span> <span class="mf">6f</span><span class="o">),</span> <span class="n">shape</span> <span class="k">=</span> <span class="nc">Shape</span><span class="o">(</span><span class="mi">3</span><span class="o">,</span> <span class="mi">2</span><span class="o">))</span> |
| <span class="k">val</span> <span class="nv">a1</span> <span class="k">=</span> <span class="nv">a</span><span class="o">.</span><span class="py">slice</span><span class="o">(</span><span class="mi">1</span><span class="o">)</span> |
| <span class="nf">assert</span><span class="o">(</span><span class="nv">a1</span><span class="o">.</span><span class="py">shape</span> <span class="o">===</span> <span class="nc">Shape</span><span class="o">(</span><span class="mi">1</span><span class="o">,</span> <span class="mi">2</span><span class="o">))</span> |
| <span class="nf">assert</span><span class="o">(</span><span class="nv">a1</span><span class="o">.</span><span class="py">toArray</span> <span class="o">===</span> <span class="nc">Array</span><span class="o">(</span><span class="mf">3f</span><span class="o">,</span> <span class="mf">4f</span><span class="o">))</span> |
| |
| <span class="k">val</span> <span class="nv">a2</span> <span class="k">=</span> <span class="nv">arr</span><span class="o">.</span><span class="py">slice</span><span class="o">(</span><span class="mi">1</span><span class="o">,</span> <span class="mi">3</span><span class="o">)</span> |
| <span class="nf">assert</span><span class="o">(</span><span class="nv">a2</span><span class="o">.</span><span class="py">shape</span> <span class="o">===</span> <span class="nc">Shape</span><span class="o">(</span><span class="mi">2</span><span class="o">,</span> <span class="mi">2</span><span class="o">))</span> |
| <span class="nf">assert</span><span class="o">(</span><span class="nv">a2</span><span class="o">.</span><span class="py">toArray</span> <span class="o">===</span> <span class="nc">Array</span><span class="o">(</span><span class="mf">3f</span><span class="o">,</span> <span class="mf">4f</span><span class="o">,</span> <span class="mf">5f</span><span class="o">,</span> <span class="mf">6f</span><span class="o">))</span> |
| </code></pre></div> |
| <h3 id="dot-product">Dot Product</h3> |
| <div class="highlight"><pre><code class="language-scala" data-lang="scala"><span class="k">import</span> <span class="nn">org.apache.mxnet._</span> |
| <span class="k">val</span> <span class="nv">arr1</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">array</span><span class="o">(</span><span class="nc">Array</span><span class="o">(</span><span class="mf">1f</span><span class="o">,</span> <span class="mf">2f</span><span class="o">),</span> <span class="n">shape</span> <span class="k">=</span> <span class="nc">Shape</span><span class="o">(</span><span class="mi">1</span><span class="o">,</span> <span class="mi">2</span><span class="o">))</span> |
| <span class="k">val</span> <span class="nv">arr2</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">array</span><span class="o">(</span><span class="nc">Array</span><span class="o">(</span><span class="mf">3f</span><span class="o">,</span> <span class="mf">4f</span><span class="o">),</span> <span class="n">shape</span> <span class="k">=</span> <span class="nc">Shape</span><span class="o">(</span><span class="mi">2</span><span class="o">,</span> <span class="mi">1</span><span class="o">))</span> |
| <span class="k">val</span> <span class="nv">res</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">dot</span><span class="o">(</span><span class="n">arr1</span><span class="o">,</span> <span class="n">arr2</span><span class="o">)</span> |
| <span class="nv">res</span><span class="o">.</span><span class="py">shape</span> |
| <span class="c1">// org.apache.mxnet.Shape = (1,1) |
| </span><span class="nv">res</span><span class="o">.</span><span class="py">toArray</span> |
| <span class="c1">// Array[Float] = Array(11.0) |
| </span></code></pre></div> |
| <h3 id="save-and-load-ndarray">Save and Load NDArray</h3> |
| |
| <p>You can use MXNet functions to save and load a list or dictionary of NDArrays from file systems, as follows:</p> |
| <div class="highlight"><pre><code class="language-scala" data-lang="scala"><span class="k">import</span> <span class="nn">org.apache.mxnet._</span> |
| <span class="k">val</span> <span class="nv">a</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">zeros</span><span class="o">(</span><span class="mi">100</span><span class="o">,</span> <span class="mi">200</span><span class="o">)</span> |
| <span class="k">val</span> <span class="nv">b</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">zeros</span><span class="o">(</span><span class="mi">100</span><span class="o">,</span> <span class="mi">200</span><span class="o">)</span> |
| <span class="c1">// save list of NDArrays |
| </span><span class="nv">NDArray</span><span class="o">.</span><span class="py">save</span><span class="o">(</span><span class="s">"/path/to/array/file"</span><span class="o">,</span> <span class="nc">Array</span><span class="o">(</span><span class="n">a</span><span class="o">,</span> <span class="n">b</span><span class="o">))</span> |
| <span class="c1">// save dictionary of NDArrays to AWS S3 |
| </span><span class="nv">NDArray</span><span class="o">.</span><span class="py">save</span><span class="o">(</span><span class="s">"s3://path/to/s3/array"</span><span class="o">,</span> <span class="nc">Map</span><span class="o">(</span><span class="s">"A"</span> <span class="o">-></span> <span class="n">a</span><span class="o">,</span> <span class="s">"B"</span> <span class="o">-></span> <span class="n">b</span><span class="o">))</span> |
| <span class="c1">// save list of NDArrays to hdfs. |
| </span><span class="nv">NDArray</span><span class="o">.</span><span class="py">save</span><span class="o">(</span><span class="s">"hdfs://path/to/hdfs/array"</span><span class="o">,</span> <span class="nc">Array</span><span class="o">(</span><span class="n">a</span><span class="o">,</span> <span class="n">b</span><span class="o">))</span> |
| <span class="k">val</span> <span class="nv">from_file</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">load</span><span class="o">(</span><span class="s">"/path/to/array/file"</span><span class="o">)</span> |
| <span class="k">val</span> <span class="nv">from_s3</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">load</span><span class="o">(</span><span class="s">"s3://path/to/s3/array"</span><span class="o">)</span> |
| <span class="k">val</span> <span class="nv">from_hdfs</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">load</span><span class="o">(</span><span class="s">"hdfs://path/to/hdfs/array"</span><span class="o">)</span> |
| </code></pre></div> |
| <p>The good thing about using the <code>save</code> and <code>load</code> interface is that you can use the format across all <code>mxnet</code> language bindings. They also already support Amazon S3 and HDFS.</p> |
| |
| <h3 id="multi-device-support">Multi-Device Support</h3> |
| |
| <p>Device information is stored in the <code>mxnet.Context</code> structure. When creating NDArray in MXNet, you can use the context argument (the default is the CPU context) to create arrays on specific devices as follows:</p> |
| <div class="highlight"><pre><code class="language-scala" data-lang="scala"><span class="k">import</span> <span class="nn">org.apache.mxnet._</span> |
| <span class="k">val</span> <span class="nv">cpu_a</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">zeros</span><span class="o">(</span><span class="mi">100</span><span class="o">,</span> <span class="mi">200</span><span class="o">)</span> |
| <span class="nv">cpu_a</span><span class="o">.</span><span class="py">context</span> |
| <span class="c1">// org.apache.mxnet.Context = cpu(0) |
| </span><span class="k">val</span> <span class="nv">ctx</span> <span class="k">=</span> <span class="nv">Context</span><span class="o">.</span><span class="py">gpu</span><span class="o">(</span><span class="mi">0</span><span class="o">)</span> |
| <span class="k">val</span> <span class="nv">gpu_b</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">zeros</span><span class="o">(</span><span class="nc">Shape</span><span class="o">(</span><span class="mi">100</span><span class="o">,</span> <span class="mi">200</span><span class="o">),</span> <span class="n">ctx</span><span class="o">)</span> |
| <span class="nv">gpu_b</span><span class="o">.</span><span class="py">context</span> |
| <span class="c1">// org.apache.mxnet.Context = gpu(0) |
| </span></code></pre></div> |
| <p>Currently, we <em>do not</em> allow operations among arrays from different contexts. To manually enable this, use the <code>copyto</code> member function to copy the content to different devices, and continue computation:</p> |
| <div class="highlight"><pre><code class="language-scala" data-lang="scala"><span class="k">import</span> <span class="nn">org.apache.mxnet._</span> |
| <span class="k">val</span> <span class="nv">x</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">zeros</span><span class="o">(</span><span class="mi">100</span><span class="o">,</span> <span class="mi">200</span><span class="o">)</span> |
| <span class="k">val</span> <span class="nv">ctx</span> <span class="k">=</span> <span class="nv">Context</span><span class="o">.</span><span class="py">gpu</span><span class="o">(</span><span class="mi">0</span><span class="o">)</span> |
| <span class="k">val</span> <span class="nv">y</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">zeros</span><span class="o">(</span><span class="nc">Shape</span><span class="o">(</span><span class="mi">100</span><span class="o">,</span> <span class="mi">200</span><span class="o">),</span> <span class="n">ctx</span><span class="o">)</span> |
| <span class="k">val</span> <span class="nv">z</span> <span class="k">=</span> <span class="n">x</span> <span class="o">+</span> <span class="n">y</span> |
| <span class="c1">// mxnet.base.MXNetError: [13:29:12] src/ndarray/ndarray.cc:33: |
| // Check failed: lhs.ctx() == rhs.ctx() operands context mismatch |
| </span><span class="k">val</span> <span class="nv">cpu_y</span> <span class="k">=</span> <span class="nv">NDArray</span><span class="o">.</span><span class="py">zeros</span><span class="o">(</span><span class="mi">100</span><span class="o">,</span> <span class="mi">200</span><span class="o">)</span> |
| <span class="nv">y</span><span class="o">.</span><span class="py">copyto</span><span class="o">(</span><span class="n">cpu_y</span><span class="o">)</span> |
| <span class="k">val</span> <span class="nv">z</span> <span class="k">=</span> <span class="n">x</span> <span class="o">+</span> <span class="n">cpu_y</span> |
| </code></pre></div> |
| <h2 id="next-steps">Next Steps</h2> |
| |
| <ul> |
| <li>See <a href="kvstore">KVStore API</a> for multi-GPU and multi-host distributed training.</li> |
| </ul> |
| </div> |
| </div> |
| |
| </div> |
| </div> |
| |
| </article> |
| |
| </main><footer class="site-footer h-card"> |
| <div class="wrapper"> |
| <div class="row"> |
| <div class="col-4"> |
| <h4 class="footer-category-title">Resources</h4> |
| <ul class="contact-list"> |
| <li><a href="/versions/1.9.1/community/contribute#mxnet-dev-communications">Mailing lists</a></li> |
| <li><a href="https://cwiki.apache.org/confluence/display/MXNET/Apache+MXNet+Home">Developer Wiki</a></li> |
| <li><a href="https://issues.apache.org/jira/projects/MXNET/issues">Jira Tracker</a></li> |
| <li><a href="https://github.com/apache/mxnet/labels/Roadmap">Github Roadmap</a></li> |
| <li><a href="https://medium.com/apache-mxnet">Blog</a></li> |
| <li><a href="https://discuss.mxnet.io">Forum</a></li> |
| <li><a href="/versions/1.9.1/community/contribute">Contribute</a></li> |
| </ul> |
| </div> |
| |
| <div class="col-4"><ul class="social-media-list"><li><a href="https://github.com/apache/mxnet"><svg class="svg-icon"><use xlink:href="/versions/1.9.1/assets/minima-social-icons.svg#github"></use></svg> <span class="username">apache/mxnet</span></a></li><li><a href="https://www.twitter.com/apachemxnet"><svg class="svg-icon"><use xlink:href="/versions/1.9.1/assets/minima-social-icons.svg#twitter"></use></svg> <span class="username">apachemxnet</span></a></li><li><a href="https://youtube.com/apachemxnet"><svg class="svg-icon"><use xlink:href="/versions/1.9.1/assets/minima-social-icons.svg#youtube"></use></svg> <span class="username">apachemxnet</span></a></li></ul> |
| </div> |
| |
| <div class="col-4 footer-text"> |
| <p>A flexible and efficient library for deep learning.</p> |
| </div> |
| </div> |
| </div> |
| </footer> |
| <footer class="site-footer2"> |
| <div class="wrapper"> |
| <div class="row"> |
| <div class="col-3"> |
| <img src="/versions/1.9.1/assets/img/asf_logo.svg" class="footer-logo col-2"> |
| </div> |
| <div class="footer-bottom-warning col-9"> |
| </p><p>"Copyright © 2017-2022, The Apache Software Foundation. Licensed under the Apache License, Version 2.0. 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> |
| </footer> |
| |
| |
| |
| |
| </body> |
| |
| </html> |
