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| <div class="section" id="autograd-package"> |
| <span id="autograd-package"></span><h1>Autograd Package<a class="headerlink" href="#autograd-package" title="Permalink to this headline">¶</a></h1> |
| <div class="admonition warning"> |
| <p class="first admonition-title">Warning</p> |
| <p class="last">This package is currently experimental and may change in the near future.</p> |
| </div> |
| <div class="section" id="overview"> |
| <span id="overview"></span><h2>Overview<a class="headerlink" href="#overview" title="Permalink to this headline">¶</a></h2> |
| <p>The <code class="docutils literal"><span class="pre">autograd</span></code> package enables automatic |
| differentiation of NDArray operations. |
| In machine learning applications, |
| <code class="docutils literal"><span class="pre">autograd</span></code> is often used to calculate the gradients |
| of loss functions with respect to parameters.</p> |
| <div class="section" id="record-vs-pause"> |
| <span id="record-vs-pause"></span><h3>Record vs Pause<a class="headerlink" href="#record-vs-pause" title="Permalink to this headline">¶</a></h3> |
| <p><code class="docutils literal"><span class="pre">autograd</span></code> records computation history on the fly to calculate gradients later. |
| This is only enabled inside a <code class="docutils literal"><span class="pre">with</span> <span class="pre">autograd.record():</span></code> block. |
| A <code class="docutils literal"><span class="pre">with</span> <span class="pre">auto_grad.pause()</span></code> block can be used inside a <code class="docutils literal"><span class="pre">record()</span></code> block |
| to temporarily disable recording.</p> |
| <p>To compute gradient with respect to an <code class="docutils literal"><span class="pre">NDArray</span></code> <code class="docutils literal"><span class="pre">x</span></code>, first call <code class="docutils literal"><span class="pre">x.attach_grad()</span></code> |
| to allocate space for the gradient. Then, start a <code class="docutils literal"><span class="pre">with</span> <span class="pre">autograd.record()</span></code> block, |
| and do some computation. Finally, call <code class="docutils literal"><span class="pre">backward()</span></code> on the result:</p> |
| <div class="highlight-python"><div class="highlight"><pre><span></span><span class="gp">>>> </span><span class="n">x</span> <span class="o">=</span> <span class="n">mx</span><span class="o">.</span><span class="n">nd</span><span class="o">.</span><span class="n">array</span><span class="p">([</span><span class="mi">1</span><span class="p">,</span><span class="mi">2</span><span class="p">,</span><span class="mi">3</span><span class="p">,</span><span class="mi">4</span><span class="p">])</span> |
| <span class="gp">>>> </span><span class="n">x</span><span class="o">.</span><span class="n">attach_grad</span><span class="p">()</span> |
| <span class="gp">>>> </span><span class="k">with</span> <span class="n">mx</span><span class="o">.</span><span class="n">autograd</span><span class="o">.</span><span class="n">record</span><span class="p">():</span> |
| <span class="gp">... </span> <span class="n">y</span> <span class="o">=</span> <span class="n">x</span> <span class="o">*</span> <span class="n">x</span> <span class="o">+</span> <span class="mi">1</span> |
| <span class="gp">>>> </span><span class="n">y</span><span class="o">.</span><span class="n">backward</span><span class="p">()</span> |
| <span class="gp">>>> </span><span class="k">print</span><span class="p">(</span><span class="n">x</span><span class="o">.</span><span class="n">grad</span><span class="p">)</span> |
| <span class="go">[ 2. 4. 6. 8.]</span> |
| <span class="go"><ndarray 4="" @cpu(0)=""></ndarray></span> |
| </pre></div> |
| </div> |
| </div> |
| </div> |
| <div class="section" id="train-mode-and-predict-mode"> |
| <span id="train-mode-and-predict-mode"></span><h2>Train mode and Predict Mode<a class="headerlink" href="#train-mode-and-predict-mode" title="Permalink to this headline">¶</a></h2> |
| <p>Some operators (Dropout, BatchNorm, etc) behave differently in |
| when training and when making predictions. |
| This can be controlled with <code class="docutils literal"><span class="pre">train_mode</span></code> and <code class="docutils literal"><span class="pre">predict_mode</span></code> scope.</p> |
| <p>By default, MXNet is in <code class="docutils literal"><span class="pre">predict_mode</span></code>. |
| A <code class="docutils literal"><span class="pre">with</span> <span class="pre">autograd.record()</span></code> block by default turns on <code class="docutils literal"><span class="pre">train_mode</span></code> |
| (equivalent to <code class="docutils literal"><span class="pre">with</span> <span class="pre">autograd.record(train_mode=True)</span></code>). |
| To compute a gradient in prediction mode (as when generating adversarial examples), |
| call record with <code class="docutils literal"><span class="pre">train_mode=False</span></code> and then call <code class="docutils literal"><span class="pre">backward(train_mode=False)</span></code></p> |
| <p>Although training usually coincides with recording, |
| this isn’t always the case. |
| To control <em>training</em> vs <em>predict_mode</em> without changing |
| <em>recording</em> vs <em>not recording</em>, |
| Use a <code class="docutils literal"><span class="pre">with</span> <span class="pre">autograd.train_mode():</span></code> |
| or <code class="docutils literal"><span class="pre">with</span> <span class="pre">autograd.predict_mode():</span></code> block.</p> |
| <p>Detailed tutorials are available in Part 1 of |
| <a class="reference external" href="http://gluon.mxnet.io/">the MXNet gluon book</a>.</p> |
| <script src="../../_static/js/auto_module_index.js" type="text/javascript"></script></div> |
| <div class="section" id="autograd"> |
| <span id="autograd"></span><h2>Autograd<a class="headerlink" href="#autograd" title="Permalink to this headline">¶</a></h2> |
| <table border="1" class="longtable docutils"> |
| <colgroup> |
| <col width="10%"/> |
| <col width="90%"/> |
| </colgroup> |
| <tbody valign="top"> |
| <tr class="row-odd"><td><a class="reference internal" href="#mxnet.autograd.record" title="mxnet.autograd.record"><code class="xref py py-obj docutils literal"><span class="pre">record</span></code></a></td> |
| <td>Returns an autograd recording scope context to be used in ‘with’ statement and captures code that needs gradients to be calculated.</td> |
| </tr> |
| <tr class="row-even"><td><a class="reference internal" href="#mxnet.autograd.pause" title="mxnet.autograd.pause"><code class="xref py py-obj docutils literal"><span class="pre">pause</span></code></a></td> |
| <td>Returns a scope context to be used in ‘with’ statement for codes that do not need gradients to be calculated.</td> |
| </tr> |
| <tr class="row-odd"><td><a class="reference internal" href="#mxnet.autograd.train_mode" title="mxnet.autograd.train_mode"><code class="xref py py-obj docutils literal"><span class="pre">train_mode</span></code></a></td> |
| <td>Returns a scope context to be used in ‘with’ statement in which forward pass behavior is set to training mode, without changing the recording states.</td> |
| </tr> |
| <tr class="row-even"><td><a class="reference internal" href="#mxnet.autograd.predict_mode" title="mxnet.autograd.predict_mode"><code class="xref py py-obj docutils literal"><span class="pre">predict_mode</span></code></a></td> |
| <td>Returns a scope context to be used in ‘with’ statement in which forward pass behavior is set to inference mode, without changing the recording states.</td> |
| </tr> |
| <tr class="row-odd"><td><a class="reference internal" href="#mxnet.autograd.backward" title="mxnet.autograd.backward"><code class="xref py py-obj docutils literal"><span class="pre">backward</span></code></a></td> |
| <td>Compute the gradients of heads w.r.t previously marked variables.</td> |
| </tr> |
| <tr class="row-even"><td><a class="reference internal" href="#mxnet.autograd.set_training" title="mxnet.autograd.set_training"><code class="xref py py-obj docutils literal"><span class="pre">set_training</span></code></a></td> |
| <td>Set status to training/predicting.</td> |
| </tr> |
| <tr class="row-odd"><td><a class="reference internal" href="#mxnet.autograd.is_training" title="mxnet.autograd.is_training"><code class="xref py py-obj docutils literal"><span class="pre">is_training</span></code></a></td> |
| <td>Get status on training/predicting.</td> |
| </tr> |
| <tr class="row-even"><td><a class="reference internal" href="#mxnet.autograd.set_recording" title="mxnet.autograd.set_recording"><code class="xref py py-obj docutils literal"><span class="pre">set_recording</span></code></a></td> |
| <td>Set status to recording/not recording.</td> |
| </tr> |
| <tr class="row-odd"><td><a class="reference internal" href="#mxnet.autograd.is_recording" title="mxnet.autograd.is_recording"><code class="xref py py-obj docutils literal"><span class="pre">is_recording</span></code></a></td> |
| <td>Get status on recording/not recording.</td> |
| </tr> |
| <tr class="row-even"><td><a class="reference internal" href="#mxnet.autograd.mark_variables" title="mxnet.autograd.mark_variables"><code class="xref py py-obj docutils literal"><span class="pre">mark_variables</span></code></a></td> |
| <td>Mark NDArrays as variables to compute gradient for autograd.</td> |
| </tr> |
| <tr class="row-odd"><td><a class="reference internal" href="#mxnet.autograd.Function" title="mxnet.autograd.Function"><code class="xref py py-obj docutils literal"><span class="pre">Function</span></code></a></td> |
| <td>User-defined differentiable function.</td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| <div class="section" id="api-reference"> |
| <span id="api-reference"></span><h2>API Reference<a class="headerlink" href="#api-reference" title="Permalink to this headline">¶</a></h2> |
| <script src="../../_static/js/auto_module_index.js" type="text/javascript"></script><span class="target" id="module-mxnet.autograd"></span><p>Autograd for NDArray.</p> |
| <dl class="function"> |
| <dt id="mxnet.autograd.set_recording"> |
| <code class="descclassname">mxnet.autograd.</code><code class="descname">set_recording</code><span class="sig-paren">(</span><em>is_recording</em><span class="sig-paren">)</span><a class="headerlink" href="#mxnet.autograd.set_recording" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Set status to recording/not recording. When recording, graph will be constructed |
| for gradient computation.</p> |
| <table class="docutils field-list" frame="void" rules="none"> |
| <col class="field-name"/> |
| <col class="field-body"/> |
| <tbody valign="top"> |
| <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>is_recording</strong> (<em>bool</em>) – </td> |
| </tr> |
| <tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"></td> |
| </tr> |
| <tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body">previous state before this set.</td> |
| </tr> |
| </tbody> |
| </table> |
| </dd></dl> |
| <dl class="function"> |
| <dt id="mxnet.autograd.set_training"> |
| <code class="descclassname">mxnet.autograd.</code><code class="descname">set_training</code><span class="sig-paren">(</span><em>train_mode</em><span class="sig-paren">)</span><a class="headerlink" href="#mxnet.autograd.set_training" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Set status to training/predicting. This affects ctx.is_train in operator |
| running context. For example, Dropout will drop inputs randomly when |
| train_mode=True while simply passing through if train_mode=False.</p> |
| <table class="docutils field-list" frame="void" rules="none"> |
| <col class="field-name"/> |
| <col class="field-body"/> |
| <tbody valign="top"> |
| <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>train_mode</strong> (<em>bool</em>) – </td> |
| </tr> |
| <tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"></td> |
| </tr> |
| <tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body">previous state before this set.</td> |
| </tr> |
| </tbody> |
| </table> |
| </dd></dl> |
| <dl class="function"> |
| <dt id="mxnet.autograd.is_recording"> |
| <code class="descclassname">mxnet.autograd.</code><code class="descname">is_recording</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#mxnet.autograd.is_recording" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Get status on recording/not recording.</p> |
| <table class="docutils field-list" frame="void" rules="none"> |
| <col class="field-name"/> |
| <col class="field-body"/> |
| <tbody valign="top"> |
| <tr class="field-odd field"><th class="field-name">Returns:</th><td class="field-body"></td> |
| </tr> |
| <tr class="field-even field"><th class="field-name">Return type:</th><td class="field-body">Current state of recording.</td> |
| </tr> |
| </tbody> |
| </table> |
| </dd></dl> |
| <dl class="function"> |
| <dt id="mxnet.autograd.is_training"> |
| <code class="descclassname">mxnet.autograd.</code><code class="descname">is_training</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#mxnet.autograd.is_training" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Get status on training/predicting.</p> |
| <table class="docutils field-list" frame="void" rules="none"> |
| <col class="field-name"/> |
| <col class="field-body"/> |
| <tbody valign="top"> |
| <tr class="field-odd field"><th class="field-name">Returns:</th><td class="field-body"></td> |
| </tr> |
| <tr class="field-even field"><th class="field-name">Return type:</th><td class="field-body">Current state of training/predicting.</td> |
| </tr> |
| </tbody> |
| </table> |
| </dd></dl> |
| <dl class="function"> |
| <dt id="mxnet.autograd.record"> |
| <code class="descclassname">mxnet.autograd.</code><code class="descname">record</code><span class="sig-paren">(</span><em>train_mode=True</em><span class="sig-paren">)</span><a class="headerlink" href="#mxnet.autograd.record" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Returns an autograd recording scope context to be used in ‘with’ statement |
| and captures code that needs gradients to be calculated.</p> |
| <div class="admonition note"> |
| <p class="first admonition-title">Note</p> |
| <p class="last">When forwarding with train_mode=False, the corresponding backward |
| should also use train_mode=False, otherwise gradient is undefined.</p> |
| </div> |
| <p>Example:</p> |
| <div class="highlight-python"><div class="highlight"><pre><span></span><span class="k">with</span> <span class="n">autograd</span><span class="o">.</span><span class="n">record</span><span class="p">():</span> |
| <span class="n">y</span> <span class="o">=</span> <span class="n">model</span><span class="p">(</span><span class="n">x</span><span class="p">)</span> |
| <span class="n">backward</span><span class="p">([</span><span class="n">y</span><span class="p">])</span> |
| <span class="n">metric</span><span class="o">.</span><span class="n">update</span><span class="p">(</span><span class="o">...</span><span class="p">)</span> |
| <span class="n">optim</span><span class="o">.</span><span class="n">step</span><span class="p">(</span><span class="o">...</span><span class="p">)</span> |
| </pre></div> |
| </div> |
| <table class="docutils field-list" frame="void" rules="none"> |
| <col class="field-name"/> |
| <col class="field-body"/> |
| <tbody valign="top"> |
| <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>train_mode</strong> (<em>bool, default True</em>) – Whether the forward pass is in training or predicting mode. This controls the behavior |
| of some layers such as Dropout, BatchNorm.</td> |
| </tr> |
| </tbody> |
| </table> |
| </dd></dl> |
| <dl class="function"> |
| <dt id="mxnet.autograd.pause"> |
| <code class="descclassname">mxnet.autograd.</code><code class="descname">pause</code><span class="sig-paren">(</span><em>train_mode=False</em><span class="sig-paren">)</span><a class="headerlink" href="#mxnet.autograd.pause" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Returns a scope context to be used in ‘with’ statement for codes that do not need |
| gradients to be calculated.</p> |
| <p>Example:</p> |
| <div class="highlight-python"><div class="highlight"><pre><span></span>with autograd.record(): |
| y = model(x) |
| backward([y]) |
| with autograd.pause(): |
| # testing, IO, gradient updates... |
| </pre></div> |
| </div> |
| <table class="docutils field-list" frame="void" rules="none"> |
| <col class="field-name"/> |
| <col class="field-body"/> |
| <tbody valign="top"> |
| <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>train_mode</strong> (<em>bool, default False</em>) – Whether to do forward for training or predicting.</td> |
| </tr> |
| </tbody> |
| </table> |
| </dd></dl> |
| <dl class="function"> |
| <dt id="mxnet.autograd.train_mode"> |
| <code class="descclassname">mxnet.autograd.</code><code class="descname">train_mode</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#mxnet.autograd.train_mode" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Returns a scope context to be used in ‘with’ statement |
| in which forward pass behavior is set to training mode, |
| without changing the recording states.</p> |
| <p>Example:</p> |
| <div class="highlight-python"><div class="highlight"><pre><span></span><span class="n">y</span> <span class="o">=</span> <span class="n">model</span><span class="p">(</span><span class="n">x</span><span class="p">)</span> |
| <span class="k">with</span> <span class="n">autograd</span><span class="o">.</span><span class="n">train_mode</span><span class="p">():</span> |
| <span class="n">y</span> <span class="o">=</span> <span class="n">dropout</span><span class="p">(</span><span class="n">y</span><span class="p">)</span> |
| </pre></div> |
| </div> |
| </dd></dl> |
| <dl class="function"> |
| <dt id="mxnet.autograd.predict_mode"> |
| <code class="descclassname">mxnet.autograd.</code><code class="descname">predict_mode</code><span class="sig-paren">(</span><span class="sig-paren">)</span><a class="headerlink" href="#mxnet.autograd.predict_mode" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Returns a scope context to be used in ‘with’ statement |
| in which forward pass behavior is set to inference mode, |
| without changing the recording states.</p> |
| <p>Example:</p> |
| <div class="highlight-python"><div class="highlight"><pre><span></span><span class="k">with</span> <span class="n">autograd</span><span class="o">.</span><span class="n">record</span><span class="p">():</span> |
| <span class="n">y</span> <span class="o">=</span> <span class="n">model</span><span class="p">(</span><span class="n">x</span><span class="p">)</span> |
| <span class="k">with</span> <span class="n">autograd</span><span class="o">.</span><span class="n">predict_mode</span><span class="p">():</span> |
| <span class="n">y</span> <span class="o">=</span> <span class="n">sampling</span><span class="p">(</span><span class="n">y</span><span class="p">)</span> |
| <span class="n">backward</span><span class="p">([</span><span class="n">y</span><span class="p">])</span> |
| </pre></div> |
| </div> |
| </dd></dl> |
| <dl class="function"> |
| <dt id="mxnet.autograd.mark_variables"> |
| <code class="descclassname">mxnet.autograd.</code><code class="descname">mark_variables</code><span class="sig-paren">(</span><em>variables</em>, <em>gradients</em>, <em>grad_reqs='write'</em><span class="sig-paren">)</span><a class="headerlink" href="#mxnet.autograd.mark_variables" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Mark NDArrays as variables to compute gradient for autograd.</p> |
| <table class="docutils field-list" frame="void" rules="none"> |
| <col class="field-name"/> |
| <col class="field-body"/> |
| <tbody valign="top"> |
| <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple"> |
| <li><strong>variables</strong> (<em>NDArray or list of NDArray</em>) – </li> |
| <li><strong>gradients</strong> (<em>NDArray or list of NDArray</em>) – </li> |
| <li><strong>grad_reqs</strong> (<em>str or list of str</em>) – </li> |
| </ul> |
| </td> |
| </tr> |
| </tbody> |
| </table> |
| </dd></dl> |
| <dl class="function"> |
| <dt id="mxnet.autograd.backward"> |
| <code class="descclassname">mxnet.autograd.</code><code class="descname">backward</code><span class="sig-paren">(</span><em>heads</em>, <em>head_grads=None</em>, <em>retain_graph=False</em>, <em>train_mode=True</em><span class="sig-paren">)</span><a class="headerlink" href="#mxnet.autograd.backward" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Compute the gradients of heads w.r.t previously marked variables.</p> |
| <table class="docutils field-list" frame="void" rules="none"> |
| <col class="field-name"/> |
| <col class="field-body"/> |
| <tbody valign="top"> |
| <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first last simple"> |
| <li><strong>heads</strong> (<em>NDArray or list of NDArray</em>) – Output NDArray(s)</li> |
| <li><strong>head_grads</strong> (<em>NDArray or list of NDArray or None</em>) – Gradients with respect to heads.</li> |
| <li><strong>train_mode</strong> (<em>bool, optional</em>) – Whether to do backward for training or predicting.</li> |
| </ul> |
| </td> |
| </tr> |
| </tbody> |
| </table> |
| </dd></dl> |
| <dl class="function"> |
| <dt id="mxnet.autograd.get_symbol"> |
| <code class="descclassname">mxnet.autograd.</code><code class="descname">get_symbol</code><span class="sig-paren">(</span><em>x</em><span class="sig-paren">)</span><a class="headerlink" href="#mxnet.autograd.get_symbol" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Retrieve recorded computation history as <cite>Symbol</cite>.</p> |
| <table class="docutils field-list" frame="void" rules="none"> |
| <col class="field-name"/> |
| <col class="field-body"/> |
| <tbody valign="top"> |
| <tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><strong>x</strong> (<a class="reference internal" href="ndarray.html#mxnet.ndarray.NDArray" title="mxnet.ndarray.NDArray"><em>NDArray</em></a>) – Array representing the head of computation graph.</td> |
| </tr> |
| <tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body">The retrieved Symbol.</td> |
| </tr> |
| <tr class="field-odd field"><th class="field-name">Return type:</th><td class="field-body"><a class="reference internal" href="symbol.html#mxnet.symbol.Symbol" title="mxnet.symbol.Symbol">Symbol</a></td> |
| </tr> |
| </tbody> |
| </table> |
| </dd></dl> |
| <dl class="class"> |
| <dt id="mxnet.autograd.Function"> |
| <em class="property">class </em><code class="descclassname">mxnet.autograd.</code><code class="descname">Function</code><a class="headerlink" href="#mxnet.autograd.Function" title="Permalink to this definition">¶</a></dt> |
| <dd><p>User-defined differentiable function.</p> |
| <p>Function allows defining both forward and backward computation for |
| custom operators. During gradient computation, the used-defined |
| backward function will be used instead of the default chain-rule. |
| You can also cast to numpy array and back for some operations in |
| forward and backward.</p> |
| <p>For example, a stable sigmoid function can be defined as:</p> |
| <div class="highlight-python"><div class="highlight"><pre><span></span><span class="k">class</span> <span class="nc">sigmoid</span><span class="p">(</span><span class="n">Function</span><span class="p">):</span> |
| <span class="k">def</span> <span class="nf">forward</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">x</span><span class="p">):</span> |
| <span class="n">y</span> <span class="o">=</span> <span class="mi">1</span> <span class="o">/</span> <span class="p">(</span><span class="mi">1</span> <span class="o">+</span> <span class="n">mx</span><span class="o">.</span><span class="n">nd</span><span class="o">.</span><span class="n">exp</span><span class="p">(</span><span class="o">-</span><span class="n">x</span><span class="p">))</span> |
| <span class="bp">self</span><span class="o">.</span><span class="n">save_for_backward</span><span class="p">(</span><span class="n">y</span><span class="p">)</span> |
| <span class="k">return</span> <span class="n">y</span> |
| |
| <span class="k">def</span> <span class="nf">backward</span><span class="p">(</span><span class="bp">self</span><span class="p">,</span> <span class="n">dy</span><span class="p">):</span> |
| <span class="c1"># backward takes as many inputs as forward's return value,</span> |
| <span class="c1"># and returns as many NDArrays as forward's arguments.</span> |
| <span class="n">y</span><span class="p">,</span> <span class="o">=</span> <span class="bp">self</span><span class="o">.</span><span class="n">saved_tensors</span> |
| <span class="k">return</span> <span class="n">y</span> <span class="o">*</span> <span class="p">(</span><span class="mi">1</span><span class="o">-</span><span class="n">y</span><span class="p">)</span> |
| </pre></div> |
| </div> |
| <dl class="method"> |
| <dt id="mxnet.autograd.Function.forward"> |
| <code class="descname">forward</code><span class="sig-paren">(</span><em>*inputs</em><span class="sig-paren">)</span><a class="headerlink" href="#mxnet.autograd.Function.forward" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Forward computation.</p> |
| </dd></dl> |
| <dl class="method"> |
| <dt id="mxnet.autograd.Function.backward"> |
| <code class="descname">backward</code><span class="sig-paren">(</span><em>*output_grads</em><span class="sig-paren">)</span><a class="headerlink" href="#mxnet.autograd.Function.backward" title="Permalink to this definition">¶</a></dt> |
| <dd><p>Backward computation.</p> |
| <p>Takes as many inputs as forward’s outputs, |
| and returns as many NDArrays as forward’s inputs.</p> |
| </dd></dl> |
| </dd></dl> |
| <script>auto_index("api-reference");</script></div> |
| </div> |
| <div class="container"> |
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| <p> </p> |
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| <div aria-label="main navigation" class="sphinxsidebar rightsidebar" role="navigation"> |
| <div class="sphinxsidebarwrapper"> |
| <h3><a href="../../index.html">Table Of Contents</a></h3> |
| <ul> |
| <li><a class="reference internal" href="#">Autograd Package</a><ul> |
| <li><a class="reference internal" href="#overview">Overview</a><ul> |
| <li><a class="reference internal" href="#record-vs-pause">Record vs Pause</a></li> |
| </ul> |
| </li> |
| <li><a class="reference internal" href="#train-mode-and-predict-mode">Train mode and Predict Mode</a></li> |
| <li><a class="reference internal" href="#autograd">Autograd</a></li> |
| <li><a class="reference internal" href="#api-reference">API Reference</a></li> |
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