http://programmer.ie/tags/autograd/ Recent content in Autograd on Programmer.ie: Modern AI programming Hugo en-us Sat, 08 Aug 2026 12:55:00 +0100 http://programmer.ie/post/pytorch-zero-to-hero-02/ Sat, 08 Aug 2026 12:55:00 +0100 http://programmer.ie/post/pytorch-zero-to-hero-02/ <h2 id="pytorch-zero-to-hero--step-02">PyTorch: Zero to Hero — Step 02</h2> <p>In the previous post we treated tensor shapes as a debugging problem rather than a mathematical vocabulary exercise.</p> <p>We are going to do the same thing with autograd.</p> <p>If you use PyTorch for any serious amount of time, you eventually see errors like:</p> <div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-text" data-lang="text"><span style="display:flex;"><span>RuntimeError: element 0 of tensors does not require grad and does not have a grad_fn </span></span></code></pre></div><p>or:</p> <div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;"><code class="language-text" data-lang="text"><span style="display:flex;"><span>RuntimeError: Trying to backward through the graph a second time... </span></span></code></pre></div><p>or worse:</p>