Google Git
Sign in
apache / mxnet-site / 5d2e45b9c41410156d7d50982069a8e0f3991694 / . / versions / 1.1.0 / _modules / mxnet / lr_scheduler.html
blob: e81fde7b12aaacd114e27ad8e7db397eb998d8ee [file] [log] [blame]
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8"/>
<meta content="IE=edge" http-equiv="X-UA-Compatible"/>
<meta content="width=device-width, initial-scale=1" name="viewport"/>
<meta content="mxnet.lr_scheduler" property="og:title">
<meta content="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/og-logo.png" property="og:image">
<meta content="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/og-logo.png" property="og:image:secure_url">
<meta content="mxnet.lr_scheduler" property="og:description"/>
<title>mxnet.lr_scheduler — mxnet documentation</title>
<link crossorigin="anonymous" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/css/bootstrap.min.css" integrity="sha384-1q8mTJOASx8j1Au+a5WDVnPi2lkFfwwEAa8hDDdjZlpLegxhjVME1fgjWPGmkzs7" rel="stylesheet"/>
<link href="https://maxcdn.bootstrapcdn.com/font-awesome/4.5.0/css/font-awesome.min.css" rel="stylesheet"/>
<link href="../../_static/basic.css" rel="stylesheet" type="text/css">
<link href="../../_static/pygments.css" rel="stylesheet" type="text/css">
<link href="../../_static/mxnet.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript">
var DOCUMENTATION_OPTIONS = {
URL_ROOT: '../../',
VERSION: '',
COLLAPSE_INDEX: false,
FILE_SUFFIX: '.html',
HAS_SOURCE: true,
SOURCELINK_SUFFIX: '.txt'
};
</script>
<script src="https://code.jquery.com/jquery-1.11.1.min.js" type="text/javascript"></script>
<script src="../../_static/underscore.js" type="text/javascript"></script>
<script src="../../_static/searchtools_custom.js" type="text/javascript"></script>
<script src="../../_static/doctools.js" type="text/javascript"></script>
<script src="../../_static/selectlang.js" type="text/javascript"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.1/MathJax.js?config=TeX-AMS-MML_HTMLorMML" type="text/javascript"></script>
<script type="text/javascript"> jQuery(function() { Search.loadIndex("/versions/1.1.0/searchindex.js"); Search.init();}); </script>
<script>
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new
Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','https://www.google-analytics.com/analytics.js','ga');
ga('create', 'UA-96378503-1', 'auto');
ga('send', 'pageview');
</script>
<!-- -->
<!-- <script type="text/javascript" src="../../_static/jquery.js"></script> -->
<!-- -->
<!-- <script type="text/javascript" src="../../_static/underscore.js"></script> -->
<!-- -->
<!-- <script type="text/javascript" src="../../_static/doctools.js"></script> -->
<!-- -->
<!-- <script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script> -->
<!-- -->
<link href="../../genindex.html" rel="index" title="Index">
<link href="../../search.html" rel="search" title="Search"/>
<link href="../index.html" rel="up" title="Module code"/>
<link href="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/mxnet-icon.png" rel="icon" type="image/png"/>
</link></link></link></meta></meta></meta></head>
<body background="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/mxnet-background-compressed.jpeg" role="document">
<div class="content-block"><div class="navbar navbar-fixed-top">
<div class="container" id="navContainer">
<div class="innder" id="header-inner">
<h1 id="logo-wrap">
<a href="../../" id="logo"><img src="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/mxnet_logo.png"/></a>
</h1>
<nav class="nav-bar" id="main-nav">
<a class="main-nav-link" href="/versions/1.1.0/install/index.html">Install</a>
<span id="dropdown-menu-position-anchor">
<a aria-expanded="true" aria-haspopup="true" class="main-nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button">Gluon <span class="caret"></span></a>
<ul class="dropdown-menu navbar-menu" id="package-dropdown-menu">
<li><a class="main-nav-link" href="/versions/1.1.0/tutorials/gluon/gluon.html">About</a></li>
<li><a class="main-nav-link" href="https://www.d2l.ai/">Dive into Deep Learning</a></li>
<li><a class="main-nav-link" href="https://gluon-cv.mxnet.io">GluonCV Toolkit</a></li>
<li><a class="main-nav-link" href="https://gluon-nlp.mxnet.io/">GluonNLP Toolkit</a></li>
</ul>
</span>
<span id="dropdown-menu-position-anchor">
<a aria-expanded="true" aria-haspopup="true" class="main-nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button">API <span class="caret"></span></a>
<ul class="dropdown-menu navbar-menu" id="package-dropdown-menu">
<li><a class="main-nav-link" href="/versions/1.1.0/api/python/index.html">Python</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/api/c++/index.html">C++</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/api/julia/index.html">Julia</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/api/perl/index.html">Perl</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/api/r/index.html">R</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/api/scala/index.html">Scala</a></li>
</ul>
</span>
<span id="dropdown-menu-position-anchor-docs">
<a aria-expanded="true" aria-haspopup="true" class="main-nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button">Docs <span class="caret"></span></a>
<ul class="dropdown-menu navbar-menu" id="package-dropdown-menu-docs">
<li><a class="main-nav-link" href="/versions/1.1.0/faq/index.html">FAQ</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/tutorials/index.html">Tutorials</a>
<li><a class="main-nav-link" href="https://github.com/apache/incubator-mxnet/tree/v1.1.0/example">Examples</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/architecture/index.html">Architecture</a></li>
<li><a class="main-nav-link" href="https://cwiki.apache.org/confluence/display/MXNET/Apache+MXNet+Home">Developer Wiki</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/model_zoo/index.html">Model Zoo</a></li>
<li><a class="main-nav-link" href="https://github.com/onnx/onnx-mxnet">ONNX</a></li>
</li></ul>
</span>
<span id="dropdown-menu-position-anchor-community">
<a aria-expanded="true" aria-haspopup="true" class="main-nav-link dropdown-toggle" data-toggle="dropdown" href="#" role="button">Community <span class="caret"></span></a>
<ul class="dropdown-menu navbar-menu" id="package-dropdown-menu-community">
<li><a class="main-nav-link" href="http://discuss.mxnet.io">Forum</a></li>
<li><a class="main-nav-link" href="https://github.com/apache/incubator-mxnet/tree/v1.1.0">Github</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/community/contribute.html">Contribute</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/community/powered_by.html">Powered By</a></li>
</ul>
</span>
<span id="dropdown-menu-position-anchor-version" style="position: relative"><a href="#" class="main-nav-link dropdown-toggle" data-toggle="dropdown" role="button" aria-haspopup="true" aria-expanded="true">1.1.0<span class="caret"></span></a><ul id="package-dropdown-menu" class="dropdown-menu"><li><a href="/">master</a></li><li><a href="/versions/1.7.0/">1.7.0</a></li><li><a href=/versions/1.6.0/>1.6.0</a></li><li><a href=/versions/1.5.0/>1.5.0</a></li><li><a href=/versions/1.4.1/>1.4.1</a></li><li><a href=/versions/1.3.1/>1.3.1</a></li><li><a href=/versions/1.2.1/>1.2.1</a></li><li><a href=/versions/1.1.0/>1.1.0</a></li><li><a href=/versions/1.0.0/>1.0.0</a></li><li><a href=/versions/0.12.1/>0.12.1</a></li><li><a href=/versions/0.11.0/>0.11.0</a></li></ul></span></nav>
<script> function getRootPath(){ return "../../" } </script>
<div class="burgerIcon dropdown">
<a class="dropdown-toggle" data-toggle="dropdown" href="#" role="button">☰</a>
<ul class="dropdown-menu" id="burgerMenu">
<li><a href="/versions/1.1.0/install/index.html">Install</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/tutorials/index.html">Tutorials</a></li>
<li class="dropdown-submenu dropdown">
<a aria-expanded="true" aria-haspopup="true" class="dropdown-toggle burger-link" data-toggle="dropdown" href="#" tabindex="-1">Gluon</a>
<ul class="dropdown-menu navbar-menu" id="package-dropdown-menu">
<li><a class="main-nav-link" href="/versions/1.1.0/tutorials/gluon/gluon.html">About</a></li>
<li><a class="main-nav-link" href="http://gluon.mxnet.io">The Straight Dope (Tutorials)</a></li>
<li><a class="main-nav-link" href="https://gluon-cv.mxnet.io">GluonCV Toolkit</a></li>
<li><a class="main-nav-link" href="https://gluon-nlp.mxnet.io/">GluonNLP Toolkit</a></li>
</ul>
</li>
<li class="dropdown-submenu">
<a aria-expanded="true" aria-haspopup="true" class="dropdown-toggle burger-link" data-toggle="dropdown" href="#" tabindex="-1">API</a>
<ul class="dropdown-menu">
<li><a class="main-nav-link" href="/versions/1.1.0/api/python/index.html">Python</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/api/c++/index.html">C++</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/api/julia/index.html">Julia</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/api/perl/index.html">Perl</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/api/r/index.html">R</a></li>
<li><a class="main-nav-link" href="/versions/1.1.0/api/scala/index.html">Scala</a></li>
</ul>
</li>
<li class="dropdown-submenu">
<a aria-expanded="true" aria-haspopup="true" class="dropdown-toggle burger-link" data-toggle="dropdown" href="#" tabindex="-1">Docs</a>
<ul class="dropdown-menu">
<li><a href="/versions/1.1.0/faq/index.html" tabindex="-1">FAQ</a></li>
<li><a href="/versions/1.1.0/tutorials/index.html" tabindex="-1">Tutorials</a></li>
<li><a href="https://github.com/apache/incubator-mxnet/tree/v1.1.0/example" tabindex="-1">Examples</a></li>
<li><a href="/versions/1.1.0/architecture/index.html" tabindex="-1">Architecture</a></li>
<li><a href="https://cwiki.apache.org/confluence/display/MXNET/Apache+MXNet+Home" tabindex="-1">Developer Wiki</a></li>
<li><a href="/versions/1.1.0/model_zoo/index.html" tabindex="-1">Gluon Model Zoo</a></li>
<li><a href="https://github.com/onnx/onnx-mxnet" tabindex="-1">ONNX</a></li>
</ul>
</li>
<li class="dropdown-submenu dropdown">
<a aria-haspopup="true" class="dropdown-toggle burger-link" data-toggle="dropdown" href="#" role="button" tabindex="-1">Community</a>
<ul class="dropdown-menu">
<li><a href="http://discuss.mxnet.io" tabindex="-1">Forum</a></li>
<li><a href="https://github.com/apache/incubator-mxnet/tree/v1.1.0" tabindex="-1">Github</a></li>
<li><a href="/versions/1.1.0/community/contribute.html" tabindex="-1">Contribute</a></li>
<li><a href="/versions/1.1.0/community/powered_by.html" tabindex="-1">Powered By</a></li>
</ul>
</li>
<li id="dropdown-menu-position-anchor-version-mobile" class="dropdown-submenu" style="position: relative"><a href="#" tabindex="-1">1.1.0</a><ul class="dropdown-menu"><li><a tabindex="-1" href=/>master</a></li><li><a tabindex="-1" href=/versions/1.6.0/>1.6.0</a></li><li><a tabindex="-1" href=/versions/1.5.0/>1.5.0</a></li><li><a tabindex="-1" href=/versions/1.4.1/>1.4.1</a></li><li><a tabindex="-1" href=/versions/1.3.1/>1.3.1</a></li><li><a tabindex="-1" href=/versions/1.2.1/>1.2.1</a></li><li><a tabindex="-1" href=/versions/1.1.0/>1.1.0</a></li><li><a tabindex="-1" href=/versions/1.0.0/>1.0.0</a></li><li><a tabindex="-1" href=/versions/0.12.1/>0.12.1</a></li><li><a tabindex="-1" href=/versions/0.11.0/>0.11.0</a></li></ul></li></ul>
</div>
<div class="plusIcon dropdown">
<a class="dropdown-toggle" data-toggle="dropdown" href="#" role="button"><span aria-hidden="true" class="glyphicon glyphicon-plus"></span></a>
<ul class="dropdown-menu dropdown-menu-right" id="plusMenu"></ul>
</div>
<div id="search-input-wrap">
<form action="../../search.html" autocomplete="off" class="" method="get" role="search">
<div class="form-group inner-addon left-addon">
<i class="glyphicon glyphicon-search"></i>
<input class="form-control" name="q" placeholder="Search" type="text"/>
</div>
<input name="check_keywords" type="hidden" value="yes">
<input name="area" type="hidden" value="default"/>
</input></form>
<div id="search-preview"></div>
</div>
<div id="searchIcon">
<span aria-hidden="true" class="glyphicon glyphicon-search"></span>
</div>
<!-- <div id="lang-select-wrap"> -->
<!-- <label id="lang-select-label"> -->
<!-- <\!-- <i class="fa fa-globe"></i> -\-> -->
<!-- <span></span> -->
<!-- </label> -->
<!-- <select id="lang-select"> -->
<!-- <option value="en">Eng</option> -->
<!-- <option value="zh">中文</option> -->
<!-- </select> -->
<!-- </div> -->
<!-- <a id="mobile-nav-toggle">
<span class="mobile-nav-toggle-bar"></span>
<span class="mobile-nav-toggle-bar"></span>
<span class="mobile-nav-toggle-bar"></span>
</a> -->
</div>
</div>
</div>
<script type="text/javascript">
$('body').css('background', 'white');
</script>
<div class="container">
<div class="row">
<div aria-label="main navigation" class="sphinxsidebar leftsidebar" role="navigation">
<div class="sphinxsidebarwrapper">
<ul>
<li class="toctree-l1"><a class="reference internal" href="../../api/python/index.html">Python Documents</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../api/r/index.html">R Documents</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../api/julia/index.html">Julia Documents</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../api/c++/index.html">C++ Documents</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../api/scala/index.html">Scala Documents</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../api/perl/index.html">Perl Documents</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../faq/index.html">HowTo Documents</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../architecture/index.html">System Documents</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../tutorials/index.html">Tutorials</a></li>
<li class="toctree-l1"><a class="reference internal" href="../../community/index.html">Community</a></li>
</ul>
</div>
</div>
<div class="content">
<div class="page-tracker"></div>
<h1>Source code for mxnet.lr_scheduler</h1><div class="highlight"><pre>
<span></span><span class="c1"># Licensed to the Apache Software Foundation (ASF) under one</span>
<span class="c1"># or more contributor license agreements. See the NOTICE file</span>
<span class="c1"># distributed with this work for additional information</span>
<span class="c1"># regarding copyright ownership. The ASF licenses this file</span>
<span class="c1"># to you under the Apache License, Version 2.0 (the</span>
<span class="c1"># "License"); you may not use this file except in compliance</span>
<span class="c1"># with the License. You may obtain a copy of the License at</span>
<span class="c1">#</span>
<span class="c1"># http://www.apache.org/licenses/LICENSE-2.0</span>
<span class="c1">#</span>
<span class="c1"># Unless required by applicable law or agreed to in writing,</span>
<span class="c1"># software distributed under the License is distributed on an</span>
<span class="c1"># "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY</span>
<span class="c1"># KIND, either express or implied. See the License for the</span>
<span class="c1"># specific language governing permissions and limitations</span>
<span class="c1"># under the License.</span>
<span class="sd">"""Scheduling learning rate."""</span>
<span class="kn">import</span> <span class="nn">logging</span>
<div class="viewcode-block" id="LRScheduler"><a class="viewcode-back" href="../../api/python/optimization/optimization.html#mxnet.lr_scheduler.LRScheduler">[docs]</a><span class="k">class</span> <span class="nc">LRScheduler</span><span class="p">(</span><span class="nb">object</span><span class="p">):</span>
<span class="sd">"""Base class of a learning rate scheduler.</span>
<span class="sd"> A scheduler returns a new learning rate based on the number of updates that have</span>
<span class="sd"> been performed.</span>
<span class="sd"> Parameters</span>
<span class="sd"> ----------</span>
<span class="sd"> base_lr : float, optional</span>
<span class="sd"> The initial learning rate.</span>
<span class="sd"> """</span>
<span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">base_lr</span><span class="o">=</span><span class="mf">0.01</span><span class="p">):</span>
<span class="bp">self</span><span class="o">.</span><span class="n">base_lr</span> <span class="o">=</span> <span class="n">base_lr</span>
<span class="k">def</span> <span class="nf">__call__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">num_update</span><span class="p">):</span>
<span class="sd">"""Return a new learning rate.</span>
<span class="sd"> The ``num_update`` is the upper bound of the number of updates applied to</span>
<span class="sd"> every weight.</span>
<span class="sd"> Assume the optimizer has updated *i*-th weight by *k_i* times, namely</span>
<span class="sd"> ``optimizer.update(i, weight_i)`` is called by *k_i* times. Then::</span>
<span class="sd"> num_update = max([k_i for all i])</span>
<span class="sd"> Parameters</span>
<span class="sd"> ----------</span>
<span class="sd"> num_update: int</span>
<span class="sd"> the maximal number of updates applied to a weight.</span>
<span class="sd"> """</span>
<span class="k">raise</span> <span class="ne">NotImplementedError</span><span class="p">(</span><span class="s2">"must override this"</span><span class="p">)</span></div>
<div class="viewcode-block" id="FactorScheduler"><a class="viewcode-back" href="../../api/python/optimization/optimization.html#mxnet.lr_scheduler.FactorScheduler">[docs]</a><span class="k">class</span> <span class="nc">FactorScheduler</span><span class="p">(</span><span class="n">LRScheduler</span><span class="p">):</span>
<span class="sd">"""Reduce the learning rate by a factor for every *n* steps.</span>
<span class="sd"> It returns a new learning rate by::</span>
<span class="sd"> base_lr * pow(factor, floor(num_update/step))</span>
<span class="sd"> Parameters</span>
<span class="sd"> ----------</span>
<span class="sd"> step : int</span>
<span class="sd"> Changes the learning rate for every n updates.</span>
<span class="sd"> factor : float, optional</span>
<span class="sd"> The factor to change the learning rate.</span>
<span class="sd"> stop_factor_lr : float, optional</span>
<span class="sd"> Stop updating the learning rate if it is less than this value.</span>
<span class="sd"> """</span>
<span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">step</span><span class="p">,</span> <span class="n">factor</span><span class="o">=</span><span class="mi">1</span><span class="p">,</span> <span class="n">stop_factor_lr</span><span class="o">=</span><span class="mf">1e-8</span><span class="p">):</span>
<span class="nb">super</span><span class="p">(</span><span class="n">FactorScheduler</span><span class="p">,</span> <span class="bp">self</span><span class="p">)</span><span class="o">.</span><span class="fm">__init__</span><span class="p">()</span>
<span class="k">if</span> <span class="n">step</span> <span class="o"><</span> <span class="mi">1</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">"Schedule step must be greater or equal than 1 round"</span><span class="p">)</span>
<span class="k">if</span> <span class="n">factor</span> <span class="o">></span> <span class="mf">1.0</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">"Factor must be no more than 1 to make lr reduce"</span><span class="p">)</span>
<span class="bp">self</span><span class="o">.</span><span class="n">step</span> <span class="o">=</span> <span class="n">step</span>
<span class="bp">self</span><span class="o">.</span><span class="n">factor</span> <span class="o">=</span> <span class="n">factor</span>
<span class="bp">self</span><span class="o">.</span><span class="n">stop_factor_lr</span> <span class="o">=</span> <span class="n">stop_factor_lr</span>
<span class="bp">self</span><span class="o">.</span><span class="n">count</span> <span class="o">=</span> <span class="mi">0</span>
<span class="k">def</span> <span class="nf">__call__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">num_update</span><span class="p">):</span>
<span class="c1"># NOTE: use while rather than if (for continuing training via load_epoch)</span>
<span class="k">while</span> <span class="n">num_update</span> <span class="o">></span> <span class="bp">self</span><span class="o">.</span><span class="n">count</span> <span class="o">+</span> <span class="bp">self</span><span class="o">.</span><span class="n">step</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">count</span> <span class="o">+=</span> <span class="bp">self</span><span class="o">.</span><span class="n">step</span>
<span class="bp">self</span><span class="o">.</span><span class="n">base_lr</span> <span class="o">*=</span> <span class="bp">self</span><span class="o">.</span><span class="n">factor</span>
<span class="k">if</span> <span class="bp">self</span><span class="o">.</span><span class="n">base_lr</span> <span class="o"><</span> <span class="bp">self</span><span class="o">.</span><span class="n">stop_factor_lr</span><span class="p">:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">base_lr</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">stop_factor_lr</span>
<span class="n">logging</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s2">"Update[</span><span class="si">%d</span><span class="s2">]: now learning rate arrived at </span><span class="si">%0.5e</span><span class="s2">, will not "</span>
<span class="s2">"change in the future"</span><span class="p">,</span> <span class="n">num_update</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">base_lr</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="n">logging</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s2">"Update[</span><span class="si">%d</span><span class="s2">]: Change learning rate to </span><span class="si">%0.5e</span><span class="s2">"</span><span class="p">,</span>
<span class="n">num_update</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">base_lr</span><span class="p">)</span>
<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">base_lr</span></div>
<div class="viewcode-block" id="MultiFactorScheduler"><a class="viewcode-back" href="../../api/python/optimization/optimization.html#mxnet.lr_scheduler.MultiFactorScheduler">[docs]</a><span class="k">class</span> <span class="nc">MultiFactorScheduler</span><span class="p">(</span><span class="n">LRScheduler</span><span class="p">):</span>
<span class="sd">"""Reduce the learning rate by given a list of steps.</span>
<span class="sd"> Assume there exists *k* such that::</span>
<span class="sd"> step[k] <= num_update and num_update < step[k+1]</span>
<span class="sd"> Then calculate the new learning rate by::</span>
<span class="sd"> base_lr * pow(factor, k+1)</span>
<span class="sd"> Parameters</span>
<span class="sd"> ----------</span>
<span class="sd"> step: list of int</span>
<span class="sd"> The list of steps to schedule a change</span>
<span class="sd"> factor: float</span>
<span class="sd"> The factor to change the learning rate.</span>
<span class="sd"> """</span>
<span class="k">def</span> <span class="nf">__init__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">step</span><span class="p">,</span> <span class="n">factor</span><span class="o">=</span><span class="mi">1</span><span class="p">):</span>
<span class="nb">super</span><span class="p">(</span><span class="n">MultiFactorScheduler</span><span class="p">,</span> <span class="bp">self</span><span class="p">)</span><span class="o">.</span><span class="fm">__init__</span><span class="p">()</span>
<span class="k">assert</span> <span class="nb">isinstance</span><span class="p">(</span><span class="n">step</span><span class="p">,</span> <span class="nb">list</span><span class="p">)</span> <span class="ow">and</span> <span class="nb">len</span><span class="p">(</span><span class="n">step</span><span class="p">)</span> <span class="o">>=</span> <span class="mi">1</span>
<span class="k">for</span> <span class="n">i</span><span class="p">,</span> <span class="n">_step</span> <span class="ow">in</span> <span class="nb">enumerate</span><span class="p">(</span><span class="n">step</span><span class="p">):</span>
<span class="k">if</span> <span class="n">i</span> <span class="o">!=</span> <span class="mi">0</span> <span class="ow">and</span> <span class="n">step</span><span class="p">[</span><span class="n">i</span><span class="p">]</span> <span class="o"><=</span> <span class="n">step</span><span class="p">[</span><span class="n">i</span><span class="o">-</span><span class="mi">1</span><span class="p">]:</span>
<span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">"Schedule step must be an increasing integer list"</span><span class="p">)</span>
<span class="k">if</span> <span class="n">_step</span> <span class="o"><</span> <span class="mi">1</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">"Schedule step must be greater or equal than 1 round"</span><span class="p">)</span>
<span class="k">if</span> <span class="n">factor</span> <span class="o">></span> <span class="mf">1.0</span><span class="p">:</span>
<span class="k">raise</span> <span class="ne">ValueError</span><span class="p">(</span><span class="s2">"Factor must be no more than 1 to make lr reduce"</span><span class="p">)</span>
<span class="bp">self</span><span class="o">.</span><span class="n">step</span> <span class="o">=</span> <span class="n">step</span>
<span class="bp">self</span><span class="o">.</span><span class="n">cur_step_ind</span> <span class="o">=</span> <span class="mi">0</span>
<span class="bp">self</span><span class="o">.</span><span class="n">factor</span> <span class="o">=</span> <span class="n">factor</span>
<span class="bp">self</span><span class="o">.</span><span class="n">count</span> <span class="o">=</span> <span class="mi">0</span>
<span class="k">def</span> <span class="nf">__call__</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">num_update</span><span class="p">):</span>
<span class="c1"># NOTE: use while rather than if (for continuing training via load_epoch)</span>
<span class="k">while</span> <span class="bp">self</span><span class="o">.</span><span class="n">cur_step_ind</span> <span class="o"><=</span> <span class="nb">len</span><span class="p">(</span><span class="bp">self</span><span class="o">.</span><span class="n">step</span><span class="p">)</span><span class="o">-</span><span class="mi">1</span><span class="p">:</span>
<span class="k">if</span> <span class="n">num_update</span> <span class="o">></span> <span class="bp">self</span><span class="o">.</span><span class="n">step</span><span class="p">[</span><span class="bp">self</span><span class="o">.</span><span class="n">cur_step_ind</span><span class="p">]:</span>
<span class="bp">self</span><span class="o">.</span><span class="n">count</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">step</span><span class="p">[</span><span class="bp">self</span><span class="o">.</span><span class="n">cur_step_ind</span><span class="p">]</span>
<span class="bp">self</span><span class="o">.</span><span class="n">cur_step_ind</span> <span class="o">+=</span> <span class="mi">1</span>
<span class="bp">self</span><span class="o">.</span><span class="n">base_lr</span> <span class="o">*=</span> <span class="bp">self</span><span class="o">.</span><span class="n">factor</span>
<span class="n">logging</span><span class="o">.</span><span class="n">info</span><span class="p">(</span><span class="s2">"Update[</span><span class="si">%d</span><span class="s2">]: Change learning rate to </span><span class="si">%0.5e</span><span class="s2">"</span><span class="p">,</span>
<span class="n">num_update</span><span class="p">,</span> <span class="bp">self</span><span class="o">.</span><span class="n">base_lr</span><span class="p">)</span>
<span class="k">else</span><span class="p">:</span>
<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">base_lr</span>
<span class="k">return</span> <span class="bp">self</span><span class="o">.</span><span class="n">base_lr</span></div>
</pre></div>
</div>
</div>
<div aria-label="main navigation" class="sphinxsidebar rightsidebar" role="navigation">
<div class="sphinxsidebarwrapper">
</div>
</div>
</div><div class="footer">
<div class="section-disclaimer">
<div class="container">
<div>
<img height="60" src="https://raw.githubusercontent.com/dmlc/web-data/master/mxnet/image/apache_incubator_logo.png"/>
<p>
Apache MXNet is an effort undergoing incubation at The Apache Software Foundation (ASF), <strong>sponsored by the <i>Apache Incubator</i></strong>. Incubation is required of all newly accepted projects until a further review indicates that the infrastructure, communications, and decision making process have stabilized in a manner consistent with other successful ASF projects. While incubation status is not necessarily a reflection of the completeness or stability of the code, it does indicate that the project has yet to be fully endorsed by the ASF.
</p>
<p>
"Copyright © 2017-2018, The Apache Software Foundation
Apache MXNet, MXNet, Apache, the Apache feather, and the Apache MXNet project logo are either registered trademarks or trademarks of the Apache Software Foundation."
</p>
</div>
</div>
</div>
</div> <!-- pagename != index -->
</div>
<script crossorigin="anonymous" integrity="sha384-0mSbJDEHialfmuBBQP6A4Qrprq5OVfW37PRR3j5ELqxss1yVqOtnepnHVP9aJ7xS" src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.6/js/bootstrap.min.js"></script>
<script src="../../_static/js/sidebar.js" type="text/javascript"></script>
<script src="../../_static/js/search.js" type="text/javascript"></script>
<script src="../../_static/js/navbar.js" type="text/javascript"></script>
<script src="../../_static/js/clipboard.min.js" type="text/javascript"></script>
<script src="../../_static/js/copycode.js" type="text/javascript"></script>
<script src="../../_static/js/page.js" type="text/javascript"></script>
<script src="../../_static/js/docversion.js" type="text/javascript"></script>
<script type="text/javascript">
$('body').ready(function () {
$('body').css('visibility', 'visible');
});
</script>
</body>
</html>