main/notes/windows.html



<!DOCTYPE html>


<html lang="en" data-content_root="" >

  <head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Windows FAQ &#8212; PyTorch main documentation</title>
  
  
  <script data-cfasync="false">
    document.documentElement.dataset.mode = localStorage.getItem("mode") || "";
    document.documentElement.dataset.theme = localStorage.getItem("theme") || "";
  </script>
  
  <!-- Loaded before other Sphinx assets -->
  <link href="../_static/styles/theme.css?digest=dfe6caa3a7d634c4db9b" rel="stylesheet" />
<link href="../_static/styles/bootstrap.css?digest=dfe6caa3a7d634c4db9b" rel="stylesheet" />
<link href="../_static/styles/pydata-sphinx-theme.css?digest=dfe6caa3a7d634c4db9b" rel="stylesheet" />

  
  <link href="../_static/vendor/fontawesome/6.5.2/css/all.min.css?digest=dfe6caa3a7d634c4db9b" rel="stylesheet" />
  <link rel="preload" as="font" type="font/woff2" crossorigin href="../_static/vendor/fontawesome/6.5.2/webfonts/fa-solid-900.woff2" />
<link rel="preload" as="font" type="font/woff2" crossorigin href="../_static/vendor/fontawesome/6.5.2/webfonts/fa-brands-400.woff2" />
<link rel="preload" as="font" type="font/woff2" crossorigin href="../_static/vendor/fontawesome/6.5.2/webfonts/fa-regular-400.woff2" />

    <link rel="stylesheet" type="text/css" href="../_static/pygments.css" />
    <link rel="stylesheet" type="text/css" href="../_static/css/theme.css" />
    <link rel="stylesheet" type="text/css" href="../_static/copybutton.css" />
    <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/npm/katex@0.13.11/dist/katex.min.css" />
    <link rel="stylesheet" type="text/css" href="../_static/katex-math.css" />
    <link rel="stylesheet" type="text/css" href="../_static/design-style.1e8bd061cd6da7fc9cf755528e8ffc24.min.css" />
    <link rel="stylesheet" type="text/css" href="../_static/css/jit.css" />
    <link rel="stylesheet" type="text/css" href="../_static/css/custom.css" />
    <link rel="stylesheet" type="text/css" href="https://cdn.jsdelivr.net/npm/katex@0.10.0-beta/dist/katex.min.css" />
  
  <!-- Pre-loaded scripts that we'll load fully later -->
  <link rel="preload" as="script" href="../_static/scripts/bootstrap.js?digest=dfe6caa3a7d634c4db9b" />
<link rel="preload" as="script" href="../_static/scripts/pydata-sphinx-theme.js?digest=dfe6caa3a7d634c4db9b" />
  <script src="../_static/vendor/fontawesome/6.5.2/js/all.min.js?digest=dfe6caa3a7d634c4db9b"></script>

    <script data-url_root="../" id="documentation_options" src="../_static/documentation_options.js"></script>
    <script src="../_static/jquery.js"></script>
    <script src="../_static/underscore.js"></script>
    <script src="../_static/_sphinx_javascript_frameworks_compat.js"></script>
    <script src="../_static/doctools.js"></script>
    <script src="../_static/sphinx_highlight.js"></script>
    <script src="../_static/clipboard.min.js"></script>
    <script src="../_static/copybutton.js"></script>
    <script src="../_static/design-tabs.js"></script>
    <script>DOCUMENTATION_OPTIONS.pagename = 'notes/windows';</script>
    <script>
        DOCUMENTATION_OPTIONS.theme_version = '0.15.4';
        DOCUMENTATION_OPTIONS.theme_switcher_json_url = 'https://docs.pytorch.org/docs/pytorch-versions.json';
        DOCUMENTATION_OPTIONS.theme_switcher_version_match = 'main';
        DOCUMENTATION_OPTIONS.show_version_warning_banner = true;
        </script>
    <link rel="index" title="Index" href="../genindex.html" />
    <link rel="search" title="Search" href="../search.html" />
    <link rel="next" title="Community" href="../community/index.html" />
    <link rel="prev" title="Serialization semantics" href="serialization.html" />

  <meta name="viewport" content="width=device-width, initial-scale=1"/>
  <meta name="docsearch:language" content="en"/>
<link rel="canonical" href="/notes/windows.html" crossorigin="anonymous">
<script src="https://code.jquery.com/jquery-3.7.1.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/list.js/2.3.1/list.min.js"></script>
<link rel="stylesheet" type="text/css" href="../_static/css/theme.css" crossorigin="anonymous">
<script type="text/javascript" src="../_static/js/theme.js"></script>
<meta property="og:image" content="../_static/img/pytorch_seo.png" />
<link rel="stylesheet" href="../_static/webfonts/all.min.css" crossorigin="anonymous">
<meta http-equiv="Content-Security-Policy" content="default-src * 'unsafe-inline' 'unsafe-eval' data: blob:; style-src * 'unsafe-inline'; script-src * 'unsafe-inline' 'unsafe-eval' blob:;">
<meta name="pytorch_project" content="docs">
<!-- Google Tag Manager (noscript) -->
<noscript><iframe src="https://www.googletagmanager.com/ns.html?id=GTM-T8XT4PS"
   height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript>
   <!-- End Google Tag Manager (noscript) -->
   <!-- Google Tag Manager -->
<script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
   new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
   j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
   'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
   j.onload = function() {
     window.dispatchEvent(new Event('gtm_loaded'));
     console.log('GTM loaded successfully');
   };
   })(window,document,'script','dataLayer','GTM-T8XT4PS');
</script>
 <!-- End Google Tag Manager -->
 <!-- Facebook Pixel Code -->
<script>
   !function(f,b,e,v,n,t,s)
   {if(f.fbq)return;n=f.fbq=function(){n.callMethod?
   n.callMethod.apply(n,arguments):n.queue.push(arguments)};
   if(!f._fbq)f._fbq=n;n.push=n;n.loaded=!0;n.version='2.0';
   n.queue=[];t=b.createElement(e);t.async=!0;
   t.src=v;s=b.getElementsByTagName(e)[0];
   s.parentNode.insertBefore(t,s)}(window,document,'script',
   'https://connect.facebook.net/en_US/fbevents.js');
   fbq('init', '243028289693773');
   fbq('track', 'PageView');
</script>
<script>
   document.documentElement.setAttribute('data-version', 'main (2.8.0a0+git31f3ee0 )');
 </script>
<noscript>
   <img height="1" width="1" src="https://www.facebook.com/tr?id=243028289693773&ev=PageView&noscript=1"/>
</noscript>
<script>
   function gtag() {
    window.dataLayer.push(arguments);
   }
</script>
<!-- End Facebook Pixel Code -->

<script async src="https://cse.google.com/cse.js?cx=e65585f8c3ea1440e"></script>

   <!--
   Search engines should not index the main version of documentation.
   Stable documentation are built without release == 'main'.
   -->
   <meta name="robots" content="noindex">


  <meta name="viewport" content="width=device-width, initial-scale=1"/>
  <meta name="docsearch:language" content="en"/>

  </head>
<body data-feedback-url="https://github.com/pytorch/pytorch" class="pytorch-body">
     <div class="container-fluid header-holder tutorials-header" id="header-holder">
   <div class="header-container-wrapper">
    <div class="header-container">
      <a class="header-logo" href="https://pytorch.org/" aria-label="PyTorch"></a>

      <div class="main-menu">
        <ul>

          <li class="main-menu-item">
          <div id="resourcesDropdownButton" data-toggle="resources-dropdown" class="resources-dropdown">
              <a class="with-down-arrow">
                <span>Learn</span>
              </a>
              <div class="resources-dropdown-menu">
                <a class="nav-dropdown-item" href="https://pytorch.org/get-started">
                  <span class=dropdown-title>Get Started</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/tutorials">
                  <span class="dropdown-title">Tutorials</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/tutorials/beginner/basics/intro.html">
                  <span class="dropdown-title">Learn the Basics</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/tutorials/recipes/recipes_index.html">
                  <span class="dropdown-title">PyTorch Recipes</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/tutorials/beginner/introyt.html">
                  <span class="dropdown-title">Intro to PyTorch - YouTube Series</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/webinars/">
                  <span class="dropdown-title">Webinars</span>
                </a>
              </div>
            </div>
          </li>

          <li class="main-menu-item">
          <div id="resourcesDropdownButton" data-toggle="resources-dropdown" class="resources-dropdown">
              <a class="with-down-arrow">
              <span>Community</span>
              </a>
              <div class="resources-dropdown-menu">
                <a class="nav-dropdown-item" href="https://landscape.pytorch.org/" target="_blank">
                  <span class="dropdown-title">Landscape</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/join-ecosystem">
                  <span class="dropdown-title">Join the Ecosystem</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/community-hub/">
                  <span class="dropdown-title">Community Hub</span>
                </a>
                <a class="nav-dropdown-item" href="https://discuss.pytorch.org/">
                  <span class="dropdown-title">Forums</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/resources">
                  <span class=dropdown-title>Developer Resources</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/contributor-awards/">
                  <span class="dropdown-title">Contributor Awards</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/community-events/">
                  <span class="dropdown-title">Community Events</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/programs/ambassadors/">
                  <span class="dropdown-title">PyTorch Ambassadors</span>
                </a>
              </div>
            </div>
          </li>

          <li class="main-menu-item">
          <div id="resourcesDropdownButton" data-toggle="resources-dropdown" class="resources-dropdown">
              <a class="with-down-arrow">
              <span>Projects</span>
              </a>
              <div class="resources-dropdown-menu">
                <a class="nav-dropdown-item" href="https://pytorch.org/projects/pytorch/">
                  <span class="dropdown-title">PyTorch</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/projects/vllm/">
                  <span class="dropdown-title">vLLM</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/projects/deepspeed/">
                  <span class="dropdown-title">DeepSpeed</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/projects/host-your-project/">
                  <span class="dropdown-title">Host Your Project</span>
                </a>
              </div>
            </div>
          </li>

          <li class="main-menu-item">
            <div id="resourcesDropdownButton" data-toggle="resources-dropdown" class="resources-dropdown">
              <a class="with-down-arrow">
              <span> Docs</span>
              </a>
              <div class="resources-dropdown-menu">
                <a class="nav-dropdown-item" href="https://pytorch.org/docs/stable/index.html">
                  <span class="dropdown-title">PyTorch</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/pytorch-domains">
                  <span class="dropdown-title">Domains</span>
                </a>
              </div>
            </div>
          </li>

          <li class="main-menu-item">
            <div id="resourcesDropdownButton" data-toggle="resources-dropdown" class="resources-dropdown">
              <a class="with-down-arrow">
              <span>Blogs & News</span>
              </a>
              <div class="resources-dropdown-menu">
                <a class="nav-dropdown-item" href="https://pytorch.org/blog/">
                  <span class="dropdown-title">Blog</span>
                </a>
                 <a class="nav-dropdown-item" href="https://pytorch.org/announcements">
                  <span class="dropdown-title">Announcements</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/case-studies/">
                  <span class="dropdown-title">Case Studies</span>
                <a class="nav-dropdown-item" href="https://pytorch.org/events">
                  <span class="dropdown-title">Events</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/newsletter">
                  <span class="dropdown-title">Newsletter</span>
                </a>
            </div>
          </li>

          <li class="main-menu-item">
            <div id="resourcesDropdownButton" data-toggle="resources-dropdown" class="resources-dropdown">
              <a class="with-down-arrow">
              <span>About</span>
              </a>
              <div class="resources-dropdown-menu">
                <a class="nav-dropdown-item" href="https://pytorch.org/foundation">
                  <span class="dropdown-title">PyTorch Foundation</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/members">
                  <span class="dropdown-title">Members</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/governing-board">
                  <span class="dropdown-title">Governing Board</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/tac">
                  <span class="dropdown-title">Technical Advisory Council</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/credits">
                  <span class="dropdown-title">Cloud Credit Program</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/staff">
                  <span class="dropdown-title">Staff</span>
                </a>
                <a class="nav-dropdown-item" href="https://pytorch.org/contact">
                  <span class="dropdown-title">Contact</span>
                </a>
              </div>
            </div>
          </li>

          <li class="main-menu-item">
            <div class="no-dropdown main-menu-button">
              <a href="https://pytorch.org/join" data-cta="join">
                JOIN
              </a>
            </div>
          </li>
        </ul>
      </div>

      <a class="main-menu-open-button" href="#" data-behavior="open-mobile-menu">
        <i class="fa-solid fa-ellipsis"></i>
      </a>
    </div>
  </div>
 </div>

 <!-- Begin Mobile Menu -->

<div class="mobile-main-menu">
  <div class="container-fluid">
    <div class="header-container-wrapper">
      <div class="mobile-main-menu-header-container">
        <a class="main-menu-close-button" href="#" data-behavior="close-mobile-menu">
        </a>
      </div>
    </div>
  </div>

  <div class="mobile-main-menu-links-container">
    <div class="main-menu">
      <ul>
         <li class="resources-mobile-menu-title">
           <a>Learn</a>
         </li>
         <ul class="resources-mobile-menu-items">
           <li>
             <a href="https://pytorch.org/get-started">Get Started</a>
           </li>
           <li>
             <a href="https://pytorch.org/tutorials">Tutorials</a>
           </li>
           <li>
             <a href="https://pytorch.org/tutorials/beginner/basics/intro.html">Learn the Basics</a>
           </li>
           <li>
             <a href="https://pytorch.org/tutorials/recipes/recipes_index.html">PyTorch Recipes</a>
           </li>
           <li>
             <a href="https://pytorch.org/tutorials/beginner/introyt.html">Introduction to PyTorch - YouTube Series</a>
           </li>
           <li>
            <a href="https://pytorch.org/webinars/">Webinars</a>
          </li>
        </ul>
         <li class="resources-mobile-menu-title">
           <a>Community</a>
         </li>
         <ul class="resources-mobile-menu-items">
          <li>
            <a href="https://landscape.pytorch.org/">Landscape</a>
          </li>
          <li>
             <a href="https://pytorch.org/join-ecosystem">Join the Ecosystem</a>
           </li>
           <li>
             <a href="https://pytorch.org/community-hub/">Community Hub</a>
           </li>
           <li>
             <a href="https://discuss.pytorch.org/">Forums</a>
           </li>
           <li>
             <a href="https://pytorch.org/resources">Developer Resources</a>
           </li>
           <li>
             <a href="https://pytorch.org/contributor-awards/">Contributor Awards</a>
           </li>
           <li>
            <a href="https://pytorch.org/community-events/">Community Events</a>
          </li>
          <li>
            <a href="https://pytorch.org/programs/ambassadors/">PyTorch Ambassadors</a>
          </li>
       </ul>

         <li class="resources-mobile-menu-title">
           <a>Projects</a>
         </li>

         <ul class="resources-mobile-menu-items">
           <li>
             <a href="https://pytorch.org/projects/pytorch/">PyTorch</a>
           </li>

           <li>
             <a href="https://pytorch.org/projects/vllm/">vLLM</a>
           </li>
           <li>
            <a href="https://pytorch.org/projects/deepspeed/">DeepSpeed</a>
          </li>
          <li>
             <a href="https://pytorch.org/projects/host-your-project/">Host Your Project</a>
           </li>
         </ul>

         <li class="resources-mobile-menu-title">
           <a>Docs</a>
         </li>

         <ul class="resources-mobile-menu-items">
          <li>
            <a href="https://pytorch.org/docs/stable/index.html">PyTorch</a>
          </li>

          <li>
            <a href="https://pytorch.org/pytorch-domains">Domains</a>
          </li>
        </ul>

        <li class="resources-mobile-menu-title">
          <a>Blog & News</a>
        </li>

         <ul class="resources-mobile-menu-items">
          <li>
            <a href="https://pytorch.org/blog/">Blog</a>
          </li>
          <li>
            <a href="https://pytorch.org/announcements">Announcements</a>
          </li>

          <li>
            <a href="https://pytorch.org/case-studies/">Case Studies</a>
          </li>
          <li>
            <a href="https://pytorch.org/events">Events</a>
          </li>
          <li>
             <a href="https://pytorch.org/newsletter">Newsletter</a>
           </li>
        </ul>

        <li class="resources-mobile-menu-title">
          <a>About</a>
        </li>

        <ul class="resources-mobile-menu-items">
          <li>
            <a href="https://pytorch.org/foundation">PyTorch Foundation</a>
          </li>
          <li>
            <a href="https://pytorch.org/members">Members</a>
          </li>
          <li>
            <a href="https://pytorch.org/governing-board">Governing Board</a>
          </li>
          <li>
            <a href="https://pytorch.org/tac">Technical Advisory Council</a>
         </li>
         <li>
             <a href="https://pytorch.org/credits">Cloud Credit Program</a>
          </li>
          <li>
             <a href="https://pytorch.org/staff">Staff</a>
          </li>
          <li>
             <a href="https://pytorch.org/contact">Contact</a>
          </li>
        </ul>
      </ul>
    </div>
  </div>
</div>

<!-- End Mobile Menu -->
   
  
  <body data-bs-spy="scroll" data-bs-target=".bd-toc-nav" data-offset="180" data-bs-root-margin="0px 0px -60%" data-default-mode="">

  
  <div id="pst-skip-link" class="skip-link d-print-none"><a href="#main-content">Skip to main content</a></div>

  
  <div id="pst-scroll-pixel-helper"></div>
  
  <button type="button" class="btn rounded-pill" id="pst-back-to-top">
    <i class="fa-solid fa-arrow-up"></i>Back to top</button>

  
  <input type="checkbox"
          class="sidebar-toggle"
          id="pst-primary-sidebar-checkbox"/>
  <label class="overlay overlay-primary" for="pst-primary-sidebar-checkbox"></label>
  
  <input type="checkbox"
          class="sidebar-toggle"
          id="pst-secondary-sidebar-checkbox"/>
  <label class="overlay overlay-secondary" for="pst-secondary-sidebar-checkbox"></label>
  
  <div class="search-button__wrapper">
    <div class="search-button__overlay"></div>
    <div class="search-button__search-container">
<form class="bd-search d-flex align-items-center"
      action="../search.html"
      method="get">
  <i class="fa-solid fa-magnifying-glass"></i>
  <input type="search"
         class="form-control"
         name="q"
         id="search-input"
         placeholder="Search the docs ..."
         aria-label="Search the docs ..."
         autocomplete="off"
         autocorrect="off"
         autocapitalize="off"
         spellcheck="false"/>
  <span class="search-button__kbd-shortcut"><kbd class="kbd-shortcut__modifier">Ctrl</kbd>+<kbd>K</kbd></span>
</form></div>
  </div>

  <div class="pst-async-banner-revealer d-none">
  <aside id="bd-header-version-warning" class="d-none d-print-none" aria-label="Version warning"></aside>
</div>

  
    <header class="bd-header navbar navbar-expand-lg bd-navbar d-print-none">
<div class="bd-header__inner bd-page-width">
  <button class="pst-navbar-icon sidebar-toggle primary-toggle" aria-label="Site navigation">
    <span class="fa-solid fa-bars"></span>
  </button>
  
  
  <div class=" navbar-header-items__start">
    
      <div class="navbar-item">
<script>
document.write(`
  <div class="version-switcher__container dropdown">
    <button id="pst-version-switcher-button-2"
      type="button"
      class="version-switcher__button btn btn-sm dropdown-toggle"
      data-bs-toggle="dropdown"
      aria-haspopup="listbox"
      aria-controls="pst-version-switcher-list-2"
      aria-label="Version switcher list"
    >
      Choose version  <!-- this text may get changed later by javascript -->
      <span class="caret"></span>
    </button>
    <div id="pst-version-switcher-list-2"
      class="version-switcher__menu dropdown-menu list-group-flush py-0"
      role="listbox" aria-labelledby="pst-version-switcher-button-2">
      <!-- dropdown will be populated by javascript on page load -->
    </div>
  </div>
`);
</script></div>
    
      <div class="navbar-item">

  
<a class="navbar-brand logo" href="../index.html">
  
  
    <p class="title logo__title">Home</p>
  
</a></div>
    
  </div>
  
  <div class=" navbar-header-items">
    
    <div class="me-auto navbar-header-items__center">
      
        <div class="navbar-item">
<nav>
  <ul class="bd-navbar-elements navbar-nav">
    
<li class="nav-item ">
  <a class="nav-link nav-internal" href="../pytorch-api.html">
    Python API
  </a>
</li>


<li class="nav-item current active">
  <a class="nav-link nav-internal" href="../notes.html">
    Developer Notes
  </a>
</li>


<li class="nav-item ">
  <a class="nav-link nav-internal" href="../community/index.html">
    Community
  </a>
</li>


<li class="nav-item ">
  <a class="nav-link nav-external" href="https://docs.pytorch.org/cppdocs/">
    C++
  </a>
</li>


<li class="nav-item ">
  <a class="nav-link nav-external" href="https://pytorch.org/tutorials/">
    Tutorials
  </a>
</li>

  </ul>
</nav></div>
      
    </div>
    
    
    <div class="navbar-header-items__end">
      
      
        <div class="navbar-item">
<div class="search-container-wrapper">
  <div id="sphinx-search" class="search-container">
    
<form class="bd-search d-flex align-items-center"
      action="../search.html"
      method="get">
  <i class="fa-solid fa-magnifying-glass"></i>
  <input type="search"
         class="form-control"
         name="q"
         id="search-input"
         placeholder="Search the docs ..."
         aria-label="Search the docs ..."
         autocomplete="off"
         autocorrect="off"
         autocapitalize="off"
         spellcheck="false"/>
  <span class="search-button__kbd-shortcut"><kbd class="kbd-shortcut__modifier">Ctrl</kbd>+<kbd>K</kbd></span>
</form>
  </div>

  <div id="google-search" class="search-container" style="display:none;">
    <div class="gcse-search-wrapper">
      <i class="fa-solid fa-magnifying-glass" aria-hidden="true"></i>
      <div class="gcse-search"></div>
    </div>
  </div>

  <div class="search-toggle-container" data-bs-title="Google Search Off" data-bs-placement="bottom" data-bs-toggle="tooltip">
    <div class="search-toggle-inner">
      <label class="switch">
        <input type="checkbox" id="search-toggle">
        <span class="slider round"></span>
      </label>
    </div>
  </div>
</div>

<script>
  document.addEventListener('DOMContentLoaded', function() {
    // Define the search callback
    const myWebSearchStartingCallback = (gname, query) => {
      if (typeof dataLayer !== 'undefined' && query) {
        window.dataLayer = window.dataLayer || [];
        dataLayer.push({
          'event': 'google_search',
          'search_term': query,
          'event_category': 'Search',
          'event_label': 'Google Search'
        });
        console.log('GA event sent via callback: google_search - ' + query);
      }
      return '';
    };

    // Set up the GCSE search callbacks
    window.__gcse || (window.__gcse = {});
    window.__gcse.searchCallbacks = {
      web: {
        starting: myWebSearchStartingCallback,
      },
    };
    if (window.location.pathname.includes('/search.html')) {
      document.body.classList.add('search-page');
    }

    // Function to reinitialize Google CSE
    function reinitializeGoogleSearch() {
      if (window.__gcse) {
        // Force Google CSE to reinitialize
        if (window.__gcse.initializationCallback) {
          window.__gcse.initializationCallback();
        }
      }
    }

    // Function to handle search toggle
    function handleSearchToggle(toggle, sphinxSearch, googleSearch) {
      if (!toggle || !sphinxSearch || !googleSearch) return;

      // Check if the URL contains /stable/ or /tutorials/
      const currentUrl = window.location.href;
      const shouldDefaultToGoogle = currentUrl.includes('/stable/') || currentUrl.includes('/tutorials/');

      // Check if there's a saved preference, otherwise use the URL-based default
      const savedPreference = localStorage.getItem('searchPreference');
      if (savedPreference === 'google' || (savedPreference === null && shouldDefaultToGoogle)) {
        toggle.checked = true;
        sphinxSearch.style.display = 'none';
        googleSearch.style.display = 'block';
        // Save the preference if it wasn't already saved
        if (savedPreference === null) {
          localStorage.setItem('searchPreference', 'google');
        }
        // Ensure Google search is properly initialized
        reinitializeGoogleSearch();
      } else {
        toggle.checked = false;
        sphinxSearch.style.display = 'block';
        googleSearch.style.display = 'none';
      }

      // Update tooltip based on initial state
      const tooltipElement = document.querySelector('.search-toggle-container');
      if (tooltipElement) {
        tooltipElement.setAttribute('data-bs-title', toggle.checked ? 'Google Search On' : 'Google Search Off');
        // Reinitialize tooltip if Bootstrap's tooltip is already initialized
        if (bootstrap && bootstrap.Tooltip) {
          const tooltipInstance = bootstrap.Tooltip.getInstance(tooltipElement);
          if (tooltipInstance) tooltipInstance.dispose();
          new bootstrap.Tooltip(tooltipElement);
        }
      }

      // Add a data attribute to track if this toggle has been initialized
      if (toggle.hasAttribute('data-initialized')) {
        return; // Skip adding another event listener if already initialized
      }
      toggle.setAttribute('data-initialized', 'true');

      toggle.addEventListener('change', function() {
        if (this.checked) {
          sphinxSearch.style.display = 'none';
          googleSearch.style.display = 'block';
          localStorage.setItem('searchPreference', 'google');
          // Reinitialize Google search when switching to it
          reinitializeGoogleSearch();
          const tooltipElement = document.querySelector('.search-toggle-container');
          if (tooltipElement) {
            tooltipElement.setAttribute('data-bs-title', 'Google Search On');
            // Refresh tooltip
            if (bootstrap && bootstrap.Tooltip) {
              const tooltipInstance = bootstrap.Tooltip.getInstance(tooltipElement);
              if (tooltipInstance) tooltipInstance.dispose();
              new bootstrap.Tooltip(tooltipElement);
            }
          }
          if (typeof dataLayer !== 'undefined') {
            window.dataLayer = window.dataLayer || [];
            dataLayer.push({
              'event': 'search_engine_switch',
              'event_category': 'Search',
              'event_label': 'Google'
            });
            console.log('GA event sent via dataLayer: search_engine_switch - Google');
          } else {
            console.log('GA not available: Cannot track Google search switch');
          }
        } else {
          sphinxSearch.style.display = 'block';
          googleSearch.style.display = 'none';
          localStorage.setItem('searchPreference', 'sphinx');
          const tooltipElement = document.querySelector('.search-toggle-container');
          if (tooltipElement) {
            tooltipElement.setAttribute('data-bs-title', 'Google Search Off');
            // Refresh tooltip
            if (bootstrap && bootstrap.Tooltip) {
              const tooltipInstance = bootstrap.Tooltip.getInstance(tooltipElement);
              if (tooltipInstance) tooltipInstance.dispose();
              new bootstrap.Tooltip(tooltipElement);
            }
          }
          if (typeof dataLayer !== 'undefined') {
            window.dataLayer = window.dataLayer || [];
            dataLayer.push({
              'event': 'search_engine_switch',
              'event_category': 'Search',
              'event_label': 'Sphinx'
            });
            console.log('GA event sent via dataLayer: search_engine_switch - Sphinx');
          } else {
            console.log('GA not available: Cannot track Sphinx search switch');
          }
        }

        // Also update mobile search if it exists
        updateMobileSearch(false); // Pass false to prevent triggering another event
      });
    }


    // Function to update mobile search based on current toggle state
    function updateMobileSearch() {
      const toggle = document.getElementById('search-toggle');
      if (!toggle) return;

      // Find mobile search container
      const mobileSearchContainer = document.querySelector('.sidebar-header-items__end .navbar-item .search-container-wrapper');
      if (mobileSearchContainer) {
        const mobileSphinxSearch = mobileSearchContainer.querySelector('#sphinx-search');
        const mobileGoogleSearch = mobileSearchContainer.querySelector('#google-search');

        if (mobileSphinxSearch && mobileGoogleSearch) {
          if (toggle.checked) {
            mobileSphinxSearch.style.display = 'none';
            mobileGoogleSearch.style.display = 'block';
            // Reinitialize Google search in mobile view
            reinitializeGoogleSearch();
          } else {
            mobileSphinxSearch.style.display = 'block';
            mobileGoogleSearch.style.display = 'none';
          }
        }
      }
    }

    // Initialize desktop search toggle
    const toggle = document.getElementById('search-toggle');
    const sphinxSearch = document.getElementById('sphinx-search');
    const googleSearch = document.getElementById('google-search');
    handleSearchToggle(toggle, sphinxSearch, googleSearch);

    // Set placeholder text for Google search input
    const observer = new MutationObserver(function(mutations, obs) {
      const searchInputs = document.querySelectorAll('.gsc-input input');
      searchInputs.forEach(input => {
      if (input) {
        input.setAttribute('placeholder', 'Search the docs ...');

        if (!input.hasAttribute('data-tracking-added')) {
          input.setAttribute('data-tracking-added', 'true');
        }
      }
      });
    });

    observer.observe(document.body, { childList: true, subtree: true });

    // Watch for mobile menu creation
    const mobileMenuObserver = new MutationObserver(function(mutations) {
      for (const mutation of mutations) {
        const mobileSearchInputs = document.querySelectorAll('.sidebar-header-items__end .navbar-item .search-container-wrapper .gsc-input input');
      mobileSearchInputs.forEach(input => {
        if (input) {
          input.setAttribute('placeholder', 'Search the docs ...');
          input.style.paddingLeft = '36px';
          }
        });
        if (mutation.addedNodes.length) {
          // Check if the mobile search container was added
          const mobileSearchContainer = document.querySelector('.sidebar-header-items__end .navbar-item .search-container-wrapper');
          if (mobileSearchContainer) {
            // Clone the toggle for mobile if needed
            const mobileToggle = mobileSearchContainer.querySelector('#search-toggle');
            if (mobileToggle) {
              // Sync mobile toggle with desktop toggle
              mobileToggle.checked = toggle.checked;

              // Update mobile search display
              updateMobileSearch();

              // Add event listener to mobile toggle
              mobileToggle.addEventListener('change', function() {
                // Sync desktop toggle with mobile toggle
                toggle.checked = this.checked;
                // Trigger change event on desktop toggle to update both
                toggle.dispatchEvent(new Event('change'));
              });
            }
          }
        }
      }
    });

    mobileMenuObserver.observe(document.body, { childList: true, subtree: true });

    // Ensure Google CSE is properly loaded
    if (window.__gcse) {
      window.__gcse.callback = function() {
        // This will run after Google CSE is fully loaded
        if (toggle && toggle.checked) {
          // If Google search is active, make sure it's properly initialized
          reinitializeGoogleSearch();
        }
      };
    } else {
      // If Google CSE hasn't loaded yet, set up a callback
      window.__gcse = {
        callback: function() {
          if (toggle && toggle.checked) {
            reinitializeGoogleSearch();
          }
        }
      };
    }
  });
</script>
</div>
      
        <div class="navbar-item">

<script>
document.write(`
  <button class="btn btn-sm nav-link pst-navbar-icon theme-switch-button" title="light/dark" aria-label="light/dark" data-bs-placement="bottom" data-bs-toggle="tooltip">
    <i class="theme-switch fa-solid fa-sun fa-lg" data-mode="light"></i>
    <i class="theme-switch fa-solid fa-moon fa-lg" data-mode="dark"></i>
    <i class="theme-switch fa-solid fa-circle-half-stroke fa-lg" data-mode="auto"></i>
  </button>
`);
</script></div>
      
        <div class="navbar-item"><ul class="navbar-icon-links"
    aria-label="Icon Links">
        <li class="nav-item">
          
          
          <a href="https://x.com/PyTorch" title="X" class="nav-link pst-navbar-icon" rel="noopener" target="_blank" data-bs-toggle="tooltip" data-bs-placement="bottom"><i class="fa-brands fa-x-twitter fa-lg" aria-hidden="true"></i>
            <span class="sr-only">X</span></a>
        </li>
        <li class="nav-item">
          
          
          <a href="https://github.com/pytorch/pytorch" title="GitHub" class="nav-link pst-navbar-icon" rel="noopener" target="_blank" data-bs-toggle="tooltip" data-bs-placement="bottom"><i class="fa-brands fa-github fa-lg" aria-hidden="true"></i>
            <span class="sr-only">GitHub</span></a>
        </li>
        <li class="nav-item">
          
          
          <a href="https://discuss.pytorch.org/" title="PyTorch Forum" class="nav-link pst-navbar-icon" rel="noopener" target="_blank" data-bs-toggle="tooltip" data-bs-placement="bottom"><i class="fa-brands fa-discourse fa-lg" aria-hidden="true"></i>
            <span class="sr-only">PyTorch Forum</span></a>
        </li>
        <li class="nav-item">
          
          
          <a href="https://pypi.org/project/torch/" title="PyPi" class="nav-link pst-navbar-icon" rel="noopener" target="_blank" data-bs-toggle="tooltip" data-bs-placement="bottom"><i class="fa-brands fa-python fa-lg" aria-hidden="true"></i>
            <span class="sr-only">PyPi</span></a>
        </li>
</ul></div>
      
    </div>
    
  </div>
  
  
    <button class="pst-navbar-icon sidebar-toggle secondary-toggle" aria-label="On this page">
      <span class="fa-solid fa-outdent"></span>
    </button>
  
</div>

    </header>
  

  <div class="bd-container">
    <div class="bd-container__inner bd-page-width">
      
      
      <div class="bd-sidebar-primary bd-sidebar">
        

  <div class="sidebar-header-items sidebar-primary__section">
    
    
      <div class="sidebar-header-items__center">
        
          
            <div class="navbar-item">
<nav>
  <ul class="bd-navbar-elements navbar-nav">
    
<li class="nav-item ">
  <a class="nav-link nav-internal" href="../pytorch-api.html">
    Python API
  </a>
</li>


<li class="nav-item current active">
  <a class="nav-link nav-internal" href="../notes.html">
    Developer Notes
  </a>
</li>


<li class="nav-item ">
  <a class="nav-link nav-internal" href="../community/index.html">
    Community
  </a>
</li>


<li class="nav-item ">
  <a class="nav-link nav-external" href="https://docs.pytorch.org/cppdocs/">
    C++
  </a>
</li>


<li class="nav-item ">
  <a class="nav-link nav-external" href="https://pytorch.org/tutorials/">
    Tutorials
  </a>
</li>

  </ul>
</nav></div>
          
        
      </div>
    
    
      <div class="sidebar-header-items__end">
        
          <div class="navbar-item">
<div class="search-container-wrapper">
  <div id="sphinx-search" class="search-container">
    
<form class="bd-search d-flex align-items-center"
      action="../search.html"
      method="get">
  <i class="fa-solid fa-magnifying-glass"></i>
  <input type="search"
         class="form-control"
         name="q"
         id="search-input"
         placeholder="Search the docs ..."
         aria-label="Search the docs ..."
         autocomplete="off"
         autocorrect="off"
         autocapitalize="off"
         spellcheck="false"/>
  <span class="search-button__kbd-shortcut"><kbd class="kbd-shortcut__modifier">Ctrl</kbd>+<kbd>K</kbd></span>
</form>
  </div>

  <div id="google-search" class="search-container" style="display:none;">
    <div class="gcse-search-wrapper">
      <i class="fa-solid fa-magnifying-glass" aria-hidden="true"></i>
      <div class="gcse-search"></div>
    </div>
  </div>

  <div class="search-toggle-container" data-bs-title="Google Search Off" data-bs-placement="bottom" data-bs-toggle="tooltip">
    <div class="search-toggle-inner">
      <label class="switch">
        <input type="checkbox" id="search-toggle">
        <span class="slider round"></span>
      </label>
    </div>
  </div>
</div>

<script>
  document.addEventListener('DOMContentLoaded', function() {
    // Define the search callback
    const myWebSearchStartingCallback = (gname, query) => {
      if (typeof dataLayer !== 'undefined' && query) {
        window.dataLayer = window.dataLayer || [];
        dataLayer.push({
          'event': 'google_search',
          'search_term': query,
          'event_category': 'Search',
          'event_label': 'Google Search'
        });
        console.log('GA event sent via callback: google_search - ' + query);
      }
      return '';
    };

    // Set up the GCSE search callbacks
    window.__gcse || (window.__gcse = {});
    window.__gcse.searchCallbacks = {
      web: {
        starting: myWebSearchStartingCallback,
      },
    };
    if (window.location.pathname.includes('/search.html')) {
      document.body.classList.add('search-page');
    }

    // Function to reinitialize Google CSE
    function reinitializeGoogleSearch() {
      if (window.__gcse) {
        // Force Google CSE to reinitialize
        if (window.__gcse.initializationCallback) {
          window.__gcse.initializationCallback();
        }
      }
    }

    // Function to handle search toggle
    function handleSearchToggle(toggle, sphinxSearch, googleSearch) {
      if (!toggle || !sphinxSearch || !googleSearch) return;

      // Check if the URL contains /stable/ or /tutorials/
      const currentUrl = window.location.href;
      const shouldDefaultToGoogle = currentUrl.includes('/stable/') || currentUrl.includes('/tutorials/');

      // Check if there's a saved preference, otherwise use the URL-based default
      const savedPreference = localStorage.getItem('searchPreference');
      if (savedPreference === 'google' || (savedPreference === null && shouldDefaultToGoogle)) {
        toggle.checked = true;
        sphinxSearch.style.display = 'none';
        googleSearch.style.display = 'block';
        // Save the preference if it wasn't already saved
        if (savedPreference === null) {
          localStorage.setItem('searchPreference', 'google');
        }
        // Ensure Google search is properly initialized
        reinitializeGoogleSearch();
      } else {
        toggle.checked = false;
        sphinxSearch.style.display = 'block';
        googleSearch.style.display = 'none';
      }

      // Update tooltip based on initial state
      const tooltipElement = document.querySelector('.search-toggle-container');
      if (tooltipElement) {
        tooltipElement.setAttribute('data-bs-title', toggle.checked ? 'Google Search On' : 'Google Search Off');
        // Reinitialize tooltip if Bootstrap's tooltip is already initialized
        if (bootstrap && bootstrap.Tooltip) {
          const tooltipInstance = bootstrap.Tooltip.getInstance(tooltipElement);
          if (tooltipInstance) tooltipInstance.dispose();
          new bootstrap.Tooltip(tooltipElement);
        }
      }

      // Add a data attribute to track if this toggle has been initialized
      if (toggle.hasAttribute('data-initialized')) {
        return; // Skip adding another event listener if already initialized
      }
      toggle.setAttribute('data-initialized', 'true');

      toggle.addEventListener('change', function() {
        if (this.checked) {
          sphinxSearch.style.display = 'none';
          googleSearch.style.display = 'block';
          localStorage.setItem('searchPreference', 'google');
          // Reinitialize Google search when switching to it
          reinitializeGoogleSearch();
          const tooltipElement = document.querySelector('.search-toggle-container');
          if (tooltipElement) {
            tooltipElement.setAttribute('data-bs-title', 'Google Search On');
            // Refresh tooltip
            if (bootstrap && bootstrap.Tooltip) {
              const tooltipInstance = bootstrap.Tooltip.getInstance(tooltipElement);
              if (tooltipInstance) tooltipInstance.dispose();
              new bootstrap.Tooltip(tooltipElement);
            }
          }
          if (typeof dataLayer !== 'undefined') {
            window.dataLayer = window.dataLayer || [];
            dataLayer.push({
              'event': 'search_engine_switch',
              'event_category': 'Search',
              'event_label': 'Google'
            });
            console.log('GA event sent via dataLayer: search_engine_switch - Google');
          } else {
            console.log('GA not available: Cannot track Google search switch');
          }
        } else {
          sphinxSearch.style.display = 'block';
          googleSearch.style.display = 'none';
          localStorage.setItem('searchPreference', 'sphinx');
          const tooltipElement = document.querySelector('.search-toggle-container');
          if (tooltipElement) {
            tooltipElement.setAttribute('data-bs-title', 'Google Search Off');
            // Refresh tooltip
            if (bootstrap && bootstrap.Tooltip) {
              const tooltipInstance = bootstrap.Tooltip.getInstance(tooltipElement);
              if (tooltipInstance) tooltipInstance.dispose();
              new bootstrap.Tooltip(tooltipElement);
            }
          }
          if (typeof dataLayer !== 'undefined') {
            window.dataLayer = window.dataLayer || [];
            dataLayer.push({
              'event': 'search_engine_switch',
              'event_category': 'Search',
              'event_label': 'Sphinx'
            });
            console.log('GA event sent via dataLayer: search_engine_switch - Sphinx');
          } else {
            console.log('GA not available: Cannot track Sphinx search switch');
          }
        }

        // Also update mobile search if it exists
        updateMobileSearch(false); // Pass false to prevent triggering another event
      });
    }


    // Function to update mobile search based on current toggle state
    function updateMobileSearch() {
      const toggle = document.getElementById('search-toggle');
      if (!toggle) return;

      // Find mobile search container
      const mobileSearchContainer = document.querySelector('.sidebar-header-items__end .navbar-item .search-container-wrapper');
      if (mobileSearchContainer) {
        const mobileSphinxSearch = mobileSearchContainer.querySelector('#sphinx-search');
        const mobileGoogleSearch = mobileSearchContainer.querySelector('#google-search');

        if (mobileSphinxSearch && mobileGoogleSearch) {
          if (toggle.checked) {
            mobileSphinxSearch.style.display = 'none';
            mobileGoogleSearch.style.display = 'block';
            // Reinitialize Google search in mobile view
            reinitializeGoogleSearch();
          } else {
            mobileSphinxSearch.style.display = 'block';
            mobileGoogleSearch.style.display = 'none';
          }
        }
      }
    }

    // Initialize desktop search toggle
    const toggle = document.getElementById('search-toggle');
    const sphinxSearch = document.getElementById('sphinx-search');
    const googleSearch = document.getElementById('google-search');
    handleSearchToggle(toggle, sphinxSearch, googleSearch);

    // Set placeholder text for Google search input
    const observer = new MutationObserver(function(mutations, obs) {
      const searchInputs = document.querySelectorAll('.gsc-input input');
      searchInputs.forEach(input => {
      if (input) {
        input.setAttribute('placeholder', 'Search the docs ...');

        if (!input.hasAttribute('data-tracking-added')) {
          input.setAttribute('data-tracking-added', 'true');
        }
      }
      });
    });

    observer.observe(document.body, { childList: true, subtree: true });

    // Watch for mobile menu creation
    const mobileMenuObserver = new MutationObserver(function(mutations) {
      for (const mutation of mutations) {
        const mobileSearchInputs = document.querySelectorAll('.sidebar-header-items__end .navbar-item .search-container-wrapper .gsc-input input');
      mobileSearchInputs.forEach(input => {
        if (input) {
          input.setAttribute('placeholder', 'Search the docs ...');
          input.style.paddingLeft = '36px';
          }
        });
        if (mutation.addedNodes.length) {
          // Check if the mobile search container was added
          const mobileSearchContainer = document.querySelector('.sidebar-header-items__end .navbar-item .search-container-wrapper');
          if (mobileSearchContainer) {
            // Clone the toggle for mobile if needed
            const mobileToggle = mobileSearchContainer.querySelector('#search-toggle');
            if (mobileToggle) {
              // Sync mobile toggle with desktop toggle
              mobileToggle.checked = toggle.checked;

              // Update mobile search display
              updateMobileSearch();

              // Add event listener to mobile toggle
              mobileToggle.addEventListener('change', function() {
                // Sync desktop toggle with mobile toggle
                toggle.checked = this.checked;
                // Trigger change event on desktop toggle to update both
                toggle.dispatchEvent(new Event('change'));
              });
            }
          }
        }
      }
    });

    mobileMenuObserver.observe(document.body, { childList: true, subtree: true });

    // Ensure Google CSE is properly loaded
    if (window.__gcse) {
      window.__gcse.callback = function() {
        // This will run after Google CSE is fully loaded
        if (toggle && toggle.checked) {
          // If Google search is active, make sure it's properly initialized
          reinitializeGoogleSearch();
        }
      };
    } else {
      // If Google CSE hasn't loaded yet, set up a callback
      window.__gcse = {
        callback: function() {
          if (toggle && toggle.checked) {
            reinitializeGoogleSearch();
          }
        }
      };
    }
  });
</script>
</div>
        
          <div class="navbar-item">

<script>
document.write(`
  <button class="btn btn-sm nav-link pst-navbar-icon theme-switch-button" title="light/dark" aria-label="light/dark" data-bs-placement="bottom" data-bs-toggle="tooltip">
    <i class="theme-switch fa-solid fa-sun fa-lg" data-mode="light"></i>
    <i class="theme-switch fa-solid fa-moon fa-lg" data-mode="dark"></i>
    <i class="theme-switch fa-solid fa-circle-half-stroke fa-lg" data-mode="auto"></i>
  </button>
`);
</script></div>
        
          <div class="navbar-item"><ul class="navbar-icon-links"
    aria-label="Icon Links">
        <li class="nav-item">
          
          
          <a href="https://x.com/PyTorch" title="X" class="nav-link pst-navbar-icon" rel="noopener" target="_blank" data-bs-toggle="tooltip" data-bs-placement="bottom"><i class="fa-brands fa-x-twitter fa-lg" aria-hidden="true"></i>
            <span class="sr-only">X</span></a>
        </li>
        <li class="nav-item">
          
          
          <a href="https://github.com/pytorch/pytorch" title="GitHub" class="nav-link pst-navbar-icon" rel="noopener" target="_blank" data-bs-toggle="tooltip" data-bs-placement="bottom"><i class="fa-brands fa-github fa-lg" aria-hidden="true"></i>
            <span class="sr-only">GitHub</span></a>
        </li>
        <li class="nav-item">
          
          
          <a href="https://discuss.pytorch.org/" title="PyTorch Forum" class="nav-link pst-navbar-icon" rel="noopener" target="_blank" data-bs-toggle="tooltip" data-bs-placement="bottom"><i class="fa-brands fa-discourse fa-lg" aria-hidden="true"></i>
            <span class="sr-only">PyTorch Forum</span></a>
        </li>
        <li class="nav-item">
          
          
          <a href="https://pypi.org/project/torch/" title="PyPi" class="nav-link pst-navbar-icon" rel="noopener" target="_blank" data-bs-toggle="tooltip" data-bs-placement="bottom"><i class="fa-brands fa-python fa-lg" aria-hidden="true"></i>
            <span class="sr-only">PyPi</span></a>
        </li>
</ul></div>
        
      </div>
    
  </div>
  
    <div class="sidebar-primary-items__start sidebar-primary__section">
        <div class="sidebar-primary-item">
<nav class="bd-docs-nav bd-links"
     aria-label="Section Navigation">
  <p class="bd-links__title" role="heading" aria-level="1">Section Navigation</p>
  <div class="bd-toc-item navbar-nav"><ul class="current nav bd-sidenav">
<li class="toctree-l1"><a class="reference internal" href="amp_examples.html">Automatic Mixed Precision examples</a></li>
<li class="toctree-l1"><a class="reference internal" href="autograd.html">Autograd mechanics</a></li>
<li class="toctree-l1"><a class="reference internal" href="broadcasting.html">Broadcasting semantics</a></li>
<li class="toctree-l1"><a class="reference internal" href="cpu_threading_torchscript_inference.html">CPU threading and TorchScript inference</a></li>
<li class="toctree-l1"><a class="reference internal" href="cuda.html">CUDA semantics</a></li>
<li class="toctree-l1"><a class="reference internal" href="custom_operators.html">PyTorch Custom Operators Landing Page</a></li>
<li class="toctree-l1"><a class="reference internal" href="ddp.html">Distributed Data Parallel</a></li>
<li class="toctree-l1"><a class="reference internal" href="extending.html">Extending PyTorch</a></li>
<li class="toctree-l1"><a class="reference internal" href="extending.func.html">Extending torch.func with autograd.Function</a></li>
<li class="toctree-l1"><a class="reference internal" href="faq.html">Frequently Asked Questions</a></li>
<li class="toctree-l1"><a class="reference internal" href="fsdp.html">FSDP Notes</a></li>
<li class="toctree-l1"><a class="reference internal" href="get_start_xpu.html">Getting Started on Intel GPU</a></li>
<li class="toctree-l1"><a class="reference internal" href="gradcheck.html">Gradcheck mechanics</a></li>
<li class="toctree-l1"><a class="reference internal" href="hip.html">HIP (ROCm) semantics</a></li>
<li class="toctree-l1"><a class="reference internal" href="large_scale_deployments.html">Features for large-scale deployments</a></li>
<li class="toctree-l1"><a class="reference internal" href="libtorch_stable_abi.html">LibTorch Stable ABI</a></li>
<li class="toctree-l1"><a class="reference internal" href="modules.html">Modules</a></li>
<li class="toctree-l1"><a class="reference internal" href="mps.html">MPS backend</a></li>
<li class="toctree-l1"><a class="reference internal" href="multiprocessing.html">Multiprocessing best practices</a></li>
<li class="toctree-l1"><a class="reference internal" href="numerical_accuracy.html">Numerical accuracy</a></li>
<li class="toctree-l1"><a class="reference internal" href="out.html">Out Notes</a></li>
<li class="toctree-l1"><a class="reference internal" href="randomness.html">Reproducibility</a></li>
<li class="toctree-l1"><a class="reference internal" href="serialization.html">Serialization semantics</a></li>
<li class="toctree-l1 current active"><a class="current reference internal" href="#">Windows FAQ</a></li>
</ul>
</div>
</nav></div>
    </div>
  
  
  <div class="sidebar-primary-items__end sidebar-primary__section">
  </div>
  
  <div id="rtd-footer-container"></div>


      </div>
      
      <main id="main-content" class="bd-main" role="main">
        
        
          <div class="bd-content">
            <div class="bd-article-container">
              
              <div class="bd-header-article d-print-none">
<div class="header-article-items header-article__inner">
  
    <div class="header-article-items__start">
      
        <div class="header-article-item">


<nav aria-label="Breadcrumb" class="d-print-none">
  <ul class="bd-breadcrumbs">
    
    <li class="breadcrumb-item breadcrumb-home">
      <a href="../index.html" class="nav-link" aria-label="Home">
        <i class="fa-solid fa-home"></i>
      </a>
    </li>
    
    <li class="breadcrumb-item"><a href="../notes.html" class="nav-link">Developer Notes</a></li>
    
    <li class="breadcrumb-item active" aria-current="page">Windows FAQ</li>
  </ul>
</nav>
</div>
      
    </div>
  
  
    <div class="header-article-items__end">
      
        <div class="header-article-item">
<div class="rating">
    Rate this Page
    <div class="stars">
        
        <span class="star" data-behavior="tutorial-rating" data-count="1" data-value="1">★</span>
        
        <span class="star" data-behavior="tutorial-rating" data-count="2" data-value="2">★</span>
        
        <span class="star" data-behavior="tutorial-rating" data-count="3" data-value="3">★</span>
        
        <span class="star" data-behavior="tutorial-rating" data-count="4" data-value="4">★</span>
        
        <span class="star" data-behavior="tutorial-rating" data-count="5" data-value="5">★</span>
        
    </div>
</div>
</div>
      
    </div>
  
</div>
</div>
              
              
<div id="searchbox"></div>
  <article class="bd-article"id="pytorch-article">
   <!-- Hidden breadcrumb schema for SEO only -->
   <div style="display:none;" itemscope itemtype="https://schema.org/BreadcrumbList">
      
        <div itemprop="itemListElement" itemscope itemtype="https://schema.org/ListItem">
          <link itemprop="item" href="../notes.html">
          <meta itemprop="name" content="Developer Notes">
          <meta itemprop="position" content="1">
        </div>
      
      <div itemprop="itemListElement" itemscope itemtype="https://schema.org/ListItem">
        <meta itemprop="name" content="Windows FAQ">
        <meta itemprop="position" content="2">
      </div>
   </div>

    
<div id="searchbox"></div>
                <article class="bd-article">
                  
  <div class="section" id="windows-faq">
<h1>Windows FAQ<a class="headerlink" href="#windows-faq" title="Permalink to this heading">#</a></h1>
<p class="date-info-last-verified" style="color: #6c6c6d; font-size: small;">Created On: Apr 23, 2018 | Last Updated On: May 20, 2025</p>
<div class="section" id="building-from-source">
<h2>Building from source<a class="headerlink" href="#building-from-source" title="Permalink to this heading">#</a></h2>
<div class="section" id="include-optional-components">
<h3>Include optional components<a class="headerlink" href="#include-optional-components" title="Permalink to this heading">#</a></h3>
<p>There are two supported components for Windows PyTorch:
MKL and MAGMA. Here are the steps to build with them.</p>
<div class="highlight-bat notranslate"><div class="highlight"><pre><span></span><span class="c1">REM Make sure you have 7z and curl installed.</span>

<span class="c1">REM Download MKL files</span>
curl https://s3.amazonaws.com/ossci-windows/mkl_2020.2.254.7z -k -O
7z x -aoa mkl_2020.2.254.7z -omkl

<span class="c1">REM Download MAGMA files</span>
<span class="c1">REM version available:</span>
<span class="c1">REM 2.5.4 (CUDA 10.1 10.2 11.0 11.1) x (Debug Release)</span>
<span class="c1">REM 2.5.3 (CUDA 10.1 10.2 11.0) x (Debug Release)</span>
<span class="c1">REM 2.5.2 (CUDA 9.2 10.0 10.1 10.2) x (Debug Release)</span>
<span class="c1">REM 2.5.1 (CUDA 9.2 10.0 10.1 10.2) x (Debug Release)</span>
<span class="k">set</span> <span class="s2">&quot;CUDA_PREFIX=cuda102&quot;</span>
<span class="k">set</span> <span class="s2">&quot;CONFIG=release&quot;</span>
<span class="k">set</span> <span class="s2">&quot;HOST=https://s3.amazonaws.com/ossci-windows&quot;</span>
curl -k <span class="s2">&quot;</span><span class="nv">%HOST%</span><span class="s2">/magma_2.5.4_</span><span class="nv">%CUDA_PREFIX%</span><span class="s2">_</span><span class="nv">%CONFIG%</span><span class="s2">.7z&quot;</span> -o magma.7z
7z x -aoa magma.7z -omagma

<span class="c1">REM Setting essential environment variables</span>
<span class="k">set</span> <span class="s2">&quot;CMAKE_INCLUDE_PATH=</span><span class="nv">%cd%</span><span class="s2">\mkl\include&quot;</span>
<span class="k">set</span> <span class="s2">&quot;LIB=</span><span class="nv">%cd%</span><span class="s2">\mkl\lib;</span><span class="nv">%LIB%</span><span class="s2">&quot;</span>
<span class="k">set</span> <span class="s2">&quot;MAGMA_HOME=</span><span class="nv">%cd%</span><span class="s2">\magma&quot;</span>
</pre></div>
</div>
</div>
<div class="section" id="speeding-cuda-build-for-windows">
<h3>Speeding CUDA build for Windows<a class="headerlink" href="#speeding-cuda-build-for-windows" title="Permalink to this heading">#</a></h3>
<p>Visual Studio doesn’t support parallel custom task currently.
As an alternative, we can use <code class="docutils literal notranslate"><span class="pre">Ninja</span></code> to parallelize CUDA
build tasks. It can be used by typing only a few lines of code.</p>
<div class="highlight-bat notranslate"><div class="highlight"><pre><span></span><span class="c1">REM Let&#39;s install ninja first.</span>
pip install ninja

<span class="c1">REM Set it as the cmake generator</span>
<span class="k">set</span> <span class="nv">CMAKE_GENERATOR</span><span class="p">=</span>Ninja
</pre></div>
</div>
</div>
<div class="section" id="one-key-install-script">
<h3>One key install script<a class="headerlink" href="#one-key-install-script" title="Permalink to this heading">#</a></h3>
<p>You can take a look at <a class="reference external" href="https://github.com/peterjc123/pytorch-scripts">this set of scripts</a>.
It will lead the way for you.</p>
</div>
</div>
<div class="section" id="extension">
<h2>Extension<a class="headerlink" href="#extension" title="Permalink to this heading">#</a></h2>
<div class="section" id="cffi-extension">
<h3>CFFI Extension<a class="headerlink" href="#cffi-extension" title="Permalink to this heading">#</a></h3>
<p>The support for CFFI Extension is very experimental. You must specify
additional <code class="docutils literal notranslate"><span class="pre">libraries</span></code> in <code class="docutils literal notranslate"><span class="pre">Extension</span></code> object to make it build on
Windows.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">ffi</span> <span class="o">=</span> <span class="n">create_extension</span><span class="p">(</span>
    <span class="s1">&#39;_ext.my_lib&#39;</span><span class="p">,</span>
    <span class="n">headers</span><span class="o">=</span><span class="n">headers</span><span class="p">,</span>
    <span class="n">sources</span><span class="o">=</span><span class="n">sources</span><span class="p">,</span>
    <span class="n">define_macros</span><span class="o">=</span><span class="n">defines</span><span class="p">,</span>
    <span class="n">relative_to</span><span class="o">=</span><span class="vm">__file__</span><span class="p">,</span>
    <span class="n">with_cuda</span><span class="o">=</span><span class="n">with_cuda</span><span class="p">,</span>
    <span class="n">extra_compile_args</span><span class="o">=</span><span class="p">[</span><span class="s2">&quot;-std=c99&quot;</span><span class="p">],</span>
    <span class="n">libraries</span><span class="o">=</span><span class="p">[</span><span class="s1">&#39;ATen&#39;</span><span class="p">,</span> <span class="s1">&#39;_C&#39;</span><span class="p">]</span> <span class="c1"># Append cuda libraries when necessary, like cudart</span>
<span class="p">)</span>
</pre></div>
</div>
</div>
<div class="section" id="cpp-extension">
<h3>Cpp Extension<a class="headerlink" href="#cpp-extension" title="Permalink to this heading">#</a></h3>
<p>This type of extension has better support compared with
the previous one. However, it still needs some manual
configuration. First, you should open the
<strong>x86_x64 Cross Tools Command Prompt for VS 2017</strong>.
And then, you can start your compiling process.</p>
</div>
</div>
<div class="section" id="installation">
<h2>Installation<a class="headerlink" href="#installation" title="Permalink to this heading">#</a></h2>
<div class="section" id="package-not-found-in-win-32-channel">
<h3>Package not found in win-32 channel.<a class="headerlink" href="#package-not-found-in-win-32-channel" title="Permalink to this heading">#</a></h3>
<div class="highlight-bat notranslate"><div class="highlight"><pre><span></span>Solving environment: failed

PackagesNotFoundError: The following packages are not available from current channels:

- pytorch

Current channels:
- https://repo.continuum.io/pkgs/main/win-32
- https://repo.continuum.io/pkgs/main/noarch
- https://repo.continuum.io/pkgs/free/win-32
- https://repo.continuum.io/pkgs/free/noarch
- https://repo.continuum.io/pkgs/r/win-32
- https://repo.continuum.io/pkgs/r/noarch
- https://repo.continuum.io/pkgs/pro/win-32
- https://repo.continuum.io/pkgs/pro/noarch
- https://repo.continuum.io/pkgs/msys2/win-32
- https://repo.continuum.io/pkgs/msys2/noarch
</pre></div>
</div>
<p>PyTorch doesn’t work on 32-bit system. Please use Windows and
Python 64-bit version.</p>
</div>
<div class="section" id="import-error">
<h3>Import error<a class="headerlink" href="#import-error" title="Permalink to this heading">#</a></h3>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">from</span> <span class="nn">torch._C</span> <span class="kn">import</span> <span class="o">*</span>

<span class="ne">ImportError</span><span class="p">:</span> <span class="n">DLL</span> <span class="n">load</span> <span class="n">failed</span><span class="p">:</span> <span class="n">The</span> <span class="n">specified</span> <span class="n">module</span> <span class="n">could</span> <span class="ow">not</span> <span class="n">be</span> <span class="n">found</span><span class="o">.</span>
</pre></div>
</div>
<p>The problem is caused by the missing of the essential files.
For the wheels package, since we didn’t pack some libraries and VS2017
redistributable files in, please make sure you install them manually.
The <a class="reference external" href="https://aka.ms/vs/15/release/VC_redist.x64.exe">VS 2017 redistributable installer</a> can be downloaded.
And you should also pay attention to your installation of Numpy. Make sure it
uses MKL instead of OpenBLAS. You may type in the following command.</p>
<div class="highlight-bat notranslate"><div class="highlight"><pre><span></span>pip install numpy mkl intel-openmp mkl_fft
</pre></div>
</div>
</div>
</div>
<div class="section" id="usage-multiprocessing">
<h2>Usage (multiprocessing)<a class="headerlink" href="#usage-multiprocessing" title="Permalink to this heading">#</a></h2>
<div class="section" id="multiprocessing-error-without-if-clause-protection">
<h3>Multiprocessing error without if-clause protection<a class="headerlink" href="#multiprocessing-error-without-if-clause-protection" title="Permalink to this heading">#</a></h3>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="ne">RuntimeError</span><span class="p">:</span>
       <span class="n">An</span> <span class="n">attempt</span> <span class="n">has</span> <span class="n">been</span> <span class="n">made</span> <span class="n">to</span> <span class="n">start</span> <span class="n">a</span> <span class="n">new</span> <span class="n">process</span> <span class="n">before</span> <span class="n">the</span>
       <span class="n">current</span> <span class="n">process</span> <span class="n">has</span> <span class="n">finished</span> <span class="n">its</span> <span class="n">bootstrapping</span> <span class="n">phase</span><span class="o">.</span>

   <span class="n">This</span> <span class="n">probably</span> <span class="n">means</span> <span class="n">that</span> <span class="n">you</span> <span class="n">are</span> <span class="ow">not</span> <span class="n">using</span> <span class="n">fork</span> <span class="n">to</span> <span class="n">start</span> <span class="n">your</span>
   <span class="n">child</span> <span class="n">processes</span> <span class="ow">and</span> <span class="n">you</span> <span class="n">have</span> <span class="n">forgotten</span> <span class="n">to</span> <span class="n">use</span> <span class="n">the</span> <span class="n">proper</span> <span class="n">idiom</span>
   <span class="ow">in</span> <span class="n">the</span> <span class="n">main</span> <span class="n">module</span><span class="p">:</span>

       <span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s1">&#39;__main__&#39;</span><span class="p">:</span>
           <span class="n">freeze_support</span><span class="p">()</span>
           <span class="o">...</span>

   <span class="n">The</span> <span class="s2">&quot;freeze_support()&quot;</span> <span class="n">line</span> <span class="n">can</span> <span class="n">be</span> <span class="n">omitted</span> <span class="k">if</span> <span class="n">the</span> <span class="n">program</span>
   <span class="ow">is</span> <span class="ow">not</span> <span class="n">going</span> <span class="n">to</span> <span class="n">be</span> <span class="n">frozen</span> <span class="n">to</span> <span class="n">produce</span> <span class="n">an</span> <span class="n">executable</span><span class="o">.</span>
</pre></div>
</div>
<p>The implementation of <code class="docutils literal notranslate"><span class="pre">multiprocessing</span></code> is different on Windows, which
uses <code class="docutils literal notranslate"><span class="pre">spawn</span></code> instead of <code class="docutils literal notranslate"><span class="pre">fork</span></code>. So we have to wrap the code with an
if-clause to protect the code from executing multiple times. Refactor
your code into the following structure.</p>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">torch</span>

<span class="k">def</span> <span class="nf">main</span><span class="p">()</span>
    <span class="k">for</span> <span class="n">i</span><span class="p">,</span> <span class="n">data</span> <span class="ow">in</span> <span class="nb">enumerate</span><span class="p">(</span><span class="n">dataloader</span><span class="p">):</span>
        <span class="c1"># do something here</span>

<span class="k">if</span> <span class="vm">__name__</span> <span class="o">==</span> <span class="s1">&#39;__main__&#39;</span><span class="p">:</span>
    <span class="n">main</span><span class="p">()</span>
</pre></div>
</div>
</div>
<div class="section" id="multiprocessing-error-broken-pipe">
<h3>Multiprocessing error “Broken pipe”<a class="headerlink" href="#multiprocessing-error-broken-pipe" title="Permalink to this heading">#</a></h3>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">ForkingPickler</span><span class="p">(</span><span class="n">file</span><span class="p">,</span> <span class="n">protocol</span><span class="p">)</span><span class="o">.</span><span class="n">dump</span><span class="p">(</span><span class="n">obj</span><span class="p">)</span>

<span class="ne">BrokenPipeError</span><span class="p">:</span> <span class="p">[</span><span class="n">Errno</span> <span class="mi">32</span><span class="p">]</span> <span class="n">Broken</span> <span class="n">pipe</span>
</pre></div>
</div>
<p>This issue happens when the child process ends before the parent process
finishes sending data. There may be something wrong with your code. You
can debug your code by reducing the <code class="docutils literal notranslate"><span class="pre">num_worker</span></code> of
<a class="reference internal" href="../data.html#torch.utils.data.DataLoader" title="torch.utils.data.DataLoader"><code class="xref py py-class docutils literal notranslate"><span class="pre">DataLoader</span></code></a> to zero and see if the issue persists.</p>
</div>
<div class="section" id="multiprocessing-error-driver-shut-down">
<h3>Multiprocessing error “driver shut down”<a class="headerlink" href="#multiprocessing-error-driver-shut-down" title="Permalink to this heading">#</a></h3>
<div class="highlight-default notranslate"><div class="highlight"><pre><span></span>Couldn’t open shared file mapping: &lt;torch_14808_1591070686&gt;, error code: &lt;1455&gt; at torch\lib\TH\THAllocator.c:154

[windows] driver shut down
</pre></div>
</div>
<p>Please update your graphics driver. If this persists, this may be that your
graphics card is too old or the calculation is too heavy for your card. Please
update the TDR settings according to this <a class="reference external" href="https://www.pugetsystems.com/labs/hpc/Working-around-TDR-in-Windows-for-a-better-GPU-computing-experience-777/">post</a>.</p>
</div>
<div class="section" id="cuda-ipc-operations">
<h3>CUDA IPC operations<a class="headerlink" href="#cuda-ipc-operations" title="Permalink to this heading">#</a></h3>
<div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="n">THCudaCheck</span> <span class="n">FAIL</span> <span class="n">file</span><span class="o">=</span><span class="n">torch</span>\<span class="n">csrc</span>\<span class="n">generic</span>\<span class="n">StorageSharing</span><span class="o">.</span><span class="n">cpp</span> <span class="n">line</span><span class="o">=</span><span class="mi">252</span> <span class="n">error</span><span class="o">=</span><span class="mi">63</span> <span class="p">:</span> <span class="n">OS</span> <span class="n">call</span> <span class="n">failed</span> <span class="ow">or</span> <span class="n">operation</span> <span class="ow">not</span> <span class="n">supported</span> <span class="n">on</span> <span class="n">this</span> <span class="n">OS</span>
</pre></div>
</div>
<p>They are not supported on Windows. Something like doing multiprocessing on CUDA
tensors cannot succeed, there are two alternatives for this.</p>
<p>1. Don’t use <code class="docutils literal notranslate"><span class="pre">multiprocessing</span></code>. Set the <code class="docutils literal notranslate"><span class="pre">num_worker</span></code> of
<a class="reference internal" href="../data.html#torch.utils.data.DataLoader" title="torch.utils.data.DataLoader"><code class="xref py py-class docutils literal notranslate"><span class="pre">DataLoader</span></code></a> to zero.</p>
<p>2. Share CPU tensors instead. Make sure your custom
<code class="xref py py-class docutils literal notranslate"><span class="pre">DataSet</span></code> returns CPU tensors.</p>
</div>
</div>
</div>


                </article>
              
  </article>

              
                <footer class="bd-footer-article">
                  <div class="footer-article-items footer-article__inner">
  
    <div class="footer-article-item">
<div class="feedback">
  
<div class="rating">
    Rate this Page
    <div class="stars">
        
        <span class="star" data-behavior="tutorial-rating" data-count="1" data-value="1">★</span>
        
        <span class="star" data-behavior="tutorial-rating" data-count="2" data-value="2">★</span>
        
        <span class="star" data-behavior="tutorial-rating" data-count="3" data-value="3">★</span>
        
        <span class="star" data-behavior="tutorial-rating" data-count="4" data-value="4">★</span>
        
        <span class="star" data-behavior="tutorial-rating" data-count="5" data-value="5">★</span>
        
    </div>
</div>

  <div class="feedback-send">
    <button class="feedback-btn"
            onclick="openGitHubIssue()"
            data-bs-title="Create a GitHub Issue"
            data-bs-placement="bottom"
            data-bs-toggle="tooltip"
            data-gtm="feedback-btn-click">Send Feedback
    </button>
  </div>
</div>


<div class="prev-next-area">
    <a class="left-prev"
       href="serialization.html"
       title="previous page">
      <i class="fa-solid fa-angle-left"></i>
      <div class="prev-next-info">
        <p class="prev-next-subtitle">previous</p>
        <p class="prev-next-title">Serialization semantics</p>
      </div>
    </a>
    <a class="right-next"
       href="../community/index.html"
       title="next page">
      <div class="prev-next-info">
        <p class="prev-next-subtitle">next</p>
        <p class="prev-next-title">Community</p>
      </div>
      <i class="fa-solid fa-angle-right"></i>
    </a>
</div>

<div class="footer-info">
  <p class="copyright">
    
      
        © Copyright PyTorch Contributors.
      
      <br/>
    
  </p>

  <p class="theme-version">
    Built with the <a href="https://pydata-sphinx-theme.readthedocs.io/en/stable/index.html">PyData Sphinx Theme</a> 0.15.4.
  </p>
</div></div>
  
</div>
                </footer>
              
              
                <footer class="prev-next-footer d-print-none">
                  
<div class="prev-next-area">
    <a class="left-prev"
       href="serialization.html"
       title="previous page">
      <i class="fa-solid fa-angle-left"></i>
      <div class="prev-next-info">
        <p class="prev-next-subtitle">previous</p>
        <p class="prev-next-title">Serialization semantics</p>
      </div>
    </a>
    <a class="right-next"
       href="../community/index.html"
       title="next page">
      <div class="prev-next-info">
        <p class="prev-next-subtitle">next</p>
        <p class="prev-next-title">Community</p>
      </div>
      <i class="fa-solid fa-angle-right"></i>
    </a>
</div>
                </footer>
              
            </div>
            
            
                <div class="bd-sidebar-secondary bd-toc">
<div class="sidebar-secondary-items sidebar-secondary__inner">
    
       <div class="sidebar-secondary-item">
<div
    id="pst-page-navigation-heading-2"
    class="page-toc tocsection onthispage">
    <i class="fa-solid fa-list"></i> On this page
  </div>
  <nav class="bd-toc-nav page-toc" aria-labelledby="pst-page-navigation-heading-2">
    <ul class="visible nav section-nav flex-column">
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#building-from-source">Building from source</a><ul class="nav section-nav flex-column">
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#include-optional-components">Include optional components</a></li>
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#speeding-cuda-build-for-windows">Speeding CUDA build for Windows</a></li>
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#one-key-install-script">One key install script</a></li>
</ul>
</li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#extension">Extension</a><ul class="nav section-nav flex-column">
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#cffi-extension">CFFI Extension</a></li>
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#cpp-extension">Cpp Extension</a></li>
</ul>
</li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#installation">Installation</a><ul class="nav section-nav flex-column">
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#package-not-found-in-win-32-channel">Package not found in win-32 channel.</a></li>
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#import-error">Import error</a></li>
</ul>
</li>
<li class="toc-h2 nav-item toc-entry"><a class="reference internal nav-link" href="#usage-multiprocessing">Usage (multiprocessing)</a><ul class="nav section-nav flex-column">
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#multiprocessing-error-without-if-clause-protection">Multiprocessing error without if-clause protection</a></li>
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#multiprocessing-error-broken-pipe">Multiprocessing error “Broken pipe”</a></li>
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#multiprocessing-error-driver-shut-down">Multiprocessing error “driver shut down”</a></li>
<li class="toc-h3 nav-item toc-entry"><a class="reference internal nav-link" href="#cuda-ipc-operations">CUDA IPC operations</a></li>
</ul>
</li>
</ul>
  </nav></div>
    
       <div class="sidebar-secondary-item">

  
  <div class="tocsection editthispage">
    <a href="https://github.com/pytorch/pytorch/edit/main/docs/source/notes/windows.rst">
      <i class="fa-solid fa-pencil"></i>
      
      
          Edit on GitHub
        
      
    </a>
  </div>
</div>
    
       <div class="sidebar-secondary-item">
    <div class="tocsection sourcelink">
      <a href="../_sources/notes/windows.rst.txt">
        <i class="fa-solid fa-file-lines"></i> Show Source
      </a>
    </div>
</div>
    

<div class="sidebar-secondary-item">
  <div class="sidebar-heading">PyTorch Libraries</div>
  <ul style="list-style-type: none; padding: 0; padding-bottom: 80px;">
  
   <li><a class="nav-link nav-external" href="https://pytorch.org/audio/stable/" style="color: var(--pst-color-text-muted)">torchaudio</a></li>
  
   <li><a class="nav-link nav-external" href="https://pytorch.org/ao" style="color: var(--pst-color-text-muted)">torchao</a></li>
  
   <li><a class="nav-link nav-external" href="https://pytorch.org/executorch" style="color: var(--pst-color-text-muted)">ExecuTorch</a></li>
  
   <li><a class="nav-link nav-external" href="https://pytorch.org/torchrec" style="color: var(--pst-color-text-muted)">torchrec</a></li>
  
   <li><a class="nav-link nav-external" href="https://pytorch.org/serve/" style="color: var(--pst-color-text-muted)">torchserve</a></li>
  
   <li><a class="nav-link nav-external" href="https://pytorch.org/data" style="color: var(--pst-color-text-muted)">torchdata</a></li>
  
   <li><a class="nav-link nav-external" href="https://pytorch.org/data" style="color: var(--pst-color-text-muted)">torchvision</a></li>
  
   <li><a class="nav-link nav-external" href="https://pytorch.org/xla" style="color: var(--pst-color-text-muted)">PyTorch on XLA Devices</a></li>
  
  </ul>
</div>

</div>
</div>
              
            
          </div>
          <footer class="bd-footer-content">
            
          </footer>
        
      </main>
    </div>
  </div>
  
  <!-- Scripts loaded after <body> so the DOM is not blocked -->
  <script src="../_static/scripts/bootstrap.js?digest=dfe6caa3a7d634c4db9b"></script>
<script src="../_static/scripts/pydata-sphinx-theme.js?digest=dfe6caa3a7d634c4db9b"></script>

   <div class="container-fluid docs-tutorials-resources" id="docs-tutorials-resources">
      <div class="container">
        <div class="row">
          <div class="col-md-4">
            <h2>Docs</h2>
            <p>Access comprehensive developer documentation for PyTorch</p>
            <a class="with-right-arrow" href="https://pytorch.org/docs/stable/index.html">View Docs</a>
          </div>

          <div class="col-md-4">
            <h2>Tutorials</h2>
            <p>Get in-depth tutorials for beginners and advanced developers</p>
            <a class="with-right-arrow" href="https://pytorch.org/tutorials">View Tutorials</a>
          </div>

          <div class="col-md-4">
            <h2>Resources</h2>
            <p>Find development resources and get your questions answered</p>
            <a class="with-right-arrow" href="https://pytorch.org/resources">View Resources</a>
          </div>
        </div>
      </div>
  </div>

  <footer class="site-footer">
      <div class="container footer-container">

          
      <div class="newsletter" id="newsletter">
  
        <p
          class="newsletter__title is-style-max-width-800"><strong>Stay in touch</strong> for updates, event info, and the latest news</p>
      
      
          <script charset="utf-8" type="text/javascript" src="//js.hsforms.net/forms/embed/v2.js"></script>
          <script>
            hbspt.forms.create({
              region: "na1",
              portalId: "8112310",
              formId: "2fb2231c-000b-4ec5-88a0-1ab242549c9e"
            });
          </script>
          
      
        <p
          class="newsletter__privacy">By submitting this form, I consent to receive marketing emails from the LF and its projects regarding their events, training, research, developments, and related announcements. I understand that I can unsubscribe at any time using the links in the footers of the emails I receive. <a href="https://www.linuxfoundation.org/privacy/">Privacy Policy</a>.</p>
          
      </div>
      
  
      <div class="lf-grid">  
        <ul class="social-links">
          <li><a href="https://www.facebook.com/pytorch" target="_blank" title="PyTorch on Facebook">
            <svg xmlns="http://www.w3.org/2000/svg" viewbox="-0.51 -0.26 26.45 26.45" aria-label="Facebook"><path fill="currentColor" d="M25.497 13.075c0-2.45-.698-4.848-2.011-6.911a12.765 12.765 0 0 0-5.398-4.73A12.671 12.671 0 0 0 11.008.38a12.705 12.705 0 0 0-6.529 2.95A12.827 12.827 0 0 0 .563 9.358a12.896 12.896 0 0 0-.07 7.201 12.831 12.831 0 0 0 3.801 6.103 12.709 12.709 0 0 0 6.471 3.078v-8.957H7.53v-3.708h3.235v-2.824c0-3.213 1.903-4.988 4.813-4.988.956.014 1.909.097 2.852.25V8.67h-1.607a1.83 1.83 0 0 0-1.518.497 1.854 1.854 0 0 0-.561 1.505v2.404h3.535l-.563 3.708h-2.97v8.957a12.725 12.725 0 0 0 7.697-4.337 12.87 12.87 0 0 0 3.054-8.328z"/></svg>	
          </a></li>
          <li><a href="https://twitter.com/pytorch" target="_blank" title="PyTorch on X">
            <svg xmlns="http://www.w3.org/2000/svg" viewbox="0 0 300 300" aria-label="X"><path fill="currentColor" d="M178.57 127.15 290.27 0h-26.46l-97.03 110.38L89.34 0H0l117.13 166.93L0 300.25h26.46l102.4-116.59 81.8 116.59h89.34M36.01 19.54H76.66l187.13 262.13h-40.66"/></svg>
          </a></li>
          <li><a href="https://www.youtube.com/pytorch" target="_blank" title="PyTorch on YouTube">
            <svg xmlns="http://www.w3.org/2000/svg" viewbox="0.21 0.27 34.45 25.07" aria-label="YouTube"><path fill="currentColor" d="M33.729 6.084s-.327-2.33-1.317-3.356a4.691 4.691 0 0 0-3.32-1.432c-4.634-.34-11.589-.34-11.589-.34h-.014s-6.954 0-11.59.342a4.692 4.692 0 0 0-3.32 1.432c-.993 1.025-1.315 3.354-1.315 3.354a52.189 52.189 0 0 0-.331 5.473v2.566c.014 1.829.125 3.656.331 5.472 0 0 .322 2.33 1.316 3.36 1.26 1.345 2.916 1.3 3.653 1.445 2.65.26 11.263.34 11.263.34s6.96-.01 11.597-.353a4.691 4.691 0 0 0 3.32-1.432c.993-1.026 1.316-3.356 1.316-3.356.206-1.817.316-3.644.33-5.473v-2.57a52.26 52.26 0 0 0-.33-5.472zM14.076 17.232V7.729l8.951 4.768-8.95 4.735z"/></svg>	
          </a></li>
          <li><a href="https://www.linkedin.com/company/pytorch" target="_blank" title="PyTorch on LinkedIn">
            <svg xmlns="http://www.w3.org/2000/svg" viewbox="-10.23 -10.23 531.96 531.96" aria-label="LinkedIn"><rect width="512" height="512" rx="0" fill="currentColor"/><circle fill="#000" cx="142" cy="138" r="37"/><path stroke="#000" stroke-width="66" d="M244 194v198M142 194v198"/><path fill="#000" d="M276 282c0-20 13-40 36-40 24 0 33 18 33 45v105h66V279c0-61-32-89-76-89-34 0-51 19-59 32"/></svg>
          </a></li>
          <li><a href="https://pytorch.slack.com" target="_blank" title="PyTorch Slack">
            <svg xmlns="http://www.w3.org/2000/svg" viewBox="0.16 -0.03 21.19 21.19" aria-label="Slack"><path fill="currentColor" d="M4.896 13.27a2.147 2.147 0 0 1-2.141 2.142A2.147 2.147 0 0 1 .613 13.27c0-1.178.963-2.141 2.142-2.141h2.141v2.141zm1.08 0c0-1.178.962-2.141 2.141-2.141s2.142.963 2.142 2.141v5.363a2.147 2.147 0 0 1-2.142 2.141 2.147 2.147 0 0 1-2.141-2.142V13.27zm2.141-8.6a2.147 2.147 0 0 1-2.141-2.14c0-1.18.962-2.142 2.141-2.142s2.142.963 2.142 2.141v2.142H8.117zm0 1.08c1.179 0 2.141.962 2.141 2.141a2.147 2.147 0 0 1-2.141 2.142H2.755A2.147 2.147 0 0 1 .613 7.89c0-1.179.963-2.141 2.142-2.141h5.362zm8.599 2.141c0-1.179.963-2.141 2.141-2.141 1.179 0 2.143.962 2.143 2.14a2.147 2.147 0 0 1-2.142 2.142h-2.141V7.89zm-1.08 0a2.147 2.147 0 0 1-2.141 2.142 2.147 2.147 0 0 1-2.141-2.142V2.53c0-1.178.962-2.141 2.141-2.141s2.142.963 2.142 2.141v5.362zm-2.141 8.6c1.179 0 2.142.962 2.142 2.14a2.147 2.147 0 0 1-2.142 2.142 2.147 2.147 0 0 1-2.141-2.141V16.49h2.141zm0-1.08a2.147 2.147 0 0 1-2.141-2.141c0-1.179.962-2.142 2.141-2.142h5.362c1.179 0 2.142.963 2.142 2.142a2.147 2.147 0 0 1-2.142 2.142h-5.362z"></path></svg>
          </a></li>
          <li><a href="https://pytorch.org/wechat" title="PyTorch on WeChat">
            <svg xmlns="http://www.w3.org/2000/svg" viewBox="0.14 -0.17 38.02 33.02" aria-label="WeChat"><path fill="currentColor" d="M26.289 10.976a12.972 12.972 0 0 0-8.742 3.53 10.386 10.386 0 0 0-3.224 8.795c-1.326-.164-2.535-.345-3.75-.448a2.332 2.332 0 0 0-1.273.216c-1.18.666-2.311 1.418-3.652 2.255.246-1.112.405-2.087.687-3.024a1.15 1.15 0 0 0-.523-1.52C1.737 17.902.02 13.601 1.307 9.165c1.189-4.1 4.11-6.587 8.077-7.884A13.54 13.54 0 0 1 24.18 5.617a10.135 10.135 0 0 1 2.109 5.359zM10.668 9.594a1.564 1.564 0 0 0-2.095-1.472 1.52 1.52 0 0 0-.895 1.964 1.502 1.502 0 0 0 1.391.966 1.545 1.545 0 0 0 1.598-1.46v.002zm8.15-1.566a1.567 1.567 0 0 0-1.528 1.543 1.528 1.528 0 0 0 1.571 1.492 1.52 1.52 0 0 0 1.375-2.117 1.518 1.518 0 0 0-1.415-.919l-.003.001z"></path><path fill="currentColor" d="M33.914 32.137c-1.075-.478-2.062-1.196-3.11-1.306-1.049-.11-2.145.494-3.24.605a10.821 10.821 0 0 1-8.781-2.864c-4.682-4.33-4.013-10.97 1.403-14.518 4.811-3.154 11.874-2.102 15.268 2.273a8.671 8.671 0 0 1-1.002 12.095c-1.046.929-1.422 1.693-.751 2.917.102.257.174.525.213.798zM21.68 20.292a1.264 1.264 0 1 0 .01-2.528 1.264 1.264 0 0 0-.01 2.528zm7.887-2.526a1.266 1.266 0 0 0-1.256 1.21 1.247 1.247 0 1 0 1.256-1.21z"></path></svg>
          </a></li>
        </ul>
      </div>
  
      <div class="privacy-policy">
        <div class="copyright">
          <p>
            &copy; PyTorch. Copyright © The Linux Foundation®. All rights reserved. The Linux Foundation has registered trademarks and uses trademarks. For more information, including terms of use, privacy policy, and trademark usage, please see our <a href="https://www.linuxfoundation.org/legal/policies">Policies</a> page. <a href="https://www.linuxfoundation.org/trademark-usage">Trademark Usage</a>. <a href="http://www.linuxfoundation.org/privacy">Privacy Policy</a>.
          </p>
        </div>
      </div>


       </div>

  <div class="cookie-banner-wrapper">
  <div class="container">
    <p class="gdpr-notice">To analyze traffic and optimize your experience, we serve cookies on this site. By clicking or navigating, you agree to allow our usage of cookies. As the current maintainers of this site, Facebook’s Cookies Policy applies. Learn more, including about available controls: <a href="https://www.facebook.com/policies/cookies/">Cookies Policy</a>.</p>
    <img class="close-button" src="../_static/img/pytorch-x.svg">
  </div>
</div>
 </footer>
   
  <footer class="bd-footer"><div class="cookie-banner-wrapper">
  <div class="container">
    <p class="gdpr-notice">To analyze traffic and optimize your experience, we serve cookies on this site. By clicking or navigating, you agree to allow our usage of cookies. As the current maintainers of this site, Facebook’s Cookies Policy applies. Learn more, including about available controls: <a href="https://www.facebook.com/policies/cookies/">Cookies Policy</a>.</p>
    <img class="close-button" src="../_static/img/pytorch-x.svg">
  </div>
</div>
<div class="bd-footer__inner bd-page-width">
  
    <div class="footer-items__start">
      
        <div class="footer-item">

  <p class="copyright">
    
      © Copyright PyTorch Contributors.
      <br/>
    
  </p>
</div>
      
        <div class="footer-item">

  <p class="sphinx-version">
    Created using <a href="https://www.sphinx-doc.org/">Sphinx</a> 5.3.0.
    <br/>
  </p>
</div>
      
    </div>
  
  
    <div class="footer-items__end">
      
        <div class="footer-item">
<p class="theme-version">
  Built with the <a href="https://pydata-sphinx-theme.readthedocs.io/en/stable/index.html">PyData Sphinx Theme</a> 0.15.4.
</p></div>
      
    </div>
  
</div>

  </footer>
   <script type="application/ld+json">
      {
         "@context": "https://schema.org",
         "@type": "Article",
         "headline": "Windows FAQ",
         "description": "PyTorch Documentation. Explore PyTorch, an open-source machine learning library that accelerates the path from research prototyping to production deployment. Discover tutorials, API references, and guides to help you build and deploy deep learning models efficiently.",
         "author": {
           "@type": "Organization",
           "name": "PyTorch Contributors"
         },
         "image": "../_static/img/pytorch_seo.png",
         "mainEntityOfPage": {
           "@type": "WebPage",
           "@id": "/notes/windows.html"
         },
         "datePublished": "Apr 23, 2018",
         "dateModified": "May 20, 2025",
         "articleBody": "Windows FAQ# Created On: Apr 23, 2018 | Last Updated On: May 20, 2025 Building from source# Include optional components# There are two supported components for Windows PyTorch: MKL and MAGMA. Here are the steps to build with them. REM Make sure you have 7z and curl installed. REM Download MKL files curl https://s3.amazonaws.com/ossci-windows/mkl_2020.2.254.7z -k -O 7z x -aoa mkl_2020.2.254.7z -omkl REM Download MAGMA files REM version available: REM 2.5.4 (CUDA 10.1 10.2 11.0 11.1) x (Debug Release) REM 2.5.3 (CUDA 10.1 10.2 11.0) x (Debug Release) REM 2.5.2 (CUDA 9.2 10.0 10.1 10.2) x (Debug Release) REM 2.5.1 (CUDA 9.2 10.0 10.1 10.2) x (Debug Release) set &#34;CUDA_PREFIX=cuda102&#34; set &#34;CONFIG=release&#34; set &#34;HOST=https://s3.amazonaws.com/ossci-windows&#34; curl -k &#34;%HOST%/magma_2.5.4_%CUDA_PREFIX%_%CONFIG%.7z&#34; -o magma.7z 7z x -aoa magma.7z -omagma REM Setting essential environment variables set &#34;CMAKE_INCLUDE_PATH=%cd%\mkl\include&#34; set &#34;LIB=%cd%\mkl\lib;%LIB%&#34; set &#34;MAGMA_HOME=%cd%\magma&#34; Speeding CUDA build for Windows# Visual Studio doesn’t support parallel custom task currently. As an alternative, we can use Ninja to parallelize CUDA build tasks. It can be used by typing only a few lines of code. REM Let&#39;s install ninja first. pip install ninja REM Set it as the cmake generator set CMAKE_GENERATOR=Ninja One key install script# You can take a look at this set of scripts. It will lead the way for you. Extension# CFFI Extension# The support for CFFI Extension is very experimental. You must specify additional libraries in Extension object to make it build on Windows. ffi = create_extension( &#39;_ext.my_lib&#39;, headers=headers, sources=sources, define_macros=defines, relative_to=__file__, with_cuda=with_cuda, extra_compile_args=[&#34;-std=c99&#34;], libraries=[&#39;ATen&#39;, &#39;_C&#39;] # Append cuda libraries when necessary, like cudart ) Cpp Extension# This type of extension has better support compared with the previous one. However, it still needs some manual configuration. First, you should open the x86_x64 Cross Tools Command Prompt for VS 2017. And then, you can start your compiling process. Installation# Package not found in win-32 channel.# Solving environment: failed PackagesNotFoundError: The following packages are not available from current channels: - pytorch Current channels: - https://repo.continuum.io/pkgs/main/win-32 - https://repo.continuum.io/pkgs/main/noarch - https://repo.continuum.io/pkgs/free/win-32 - https://repo.continuum.io/pkgs/free/noarch - https://repo.continuum.io/pkgs/r/win-32 - https://repo.continuum.io/pkgs/r/noarch - https://repo.continuum.io/pkgs/pro/win-32 - https://repo.continuum.io/pkgs/pro/noarch - https://repo.continuum.io/pkgs/msys2/win-32 - https://repo.continuum.io/pkgs/msys2/noarch PyTorch doesn’t work on 32-bit system. Please use Windows and Python 64-bit version. Import error# from torch._C import * ImportError: DLL load failed: The specified module could not be found. The problem is caused by the missing of the essential files. For ..."
       }
   </script>

  </body>
</html>