I am a fresh of leaning PyTorch. When try to train the PCL, I got the fellow error and don’t know how to adress it. Thanks in advance.

lbs: <p><div class="lightbox-wrapper"><a class="lightbox" href="https://discuss.pytorch.org/uploads/default/original/3X/2/a/2a3d26f8e9aa7de9aad64d4afcb372c4797f0447.png" data-download-href="https://discuss.pytorch.org/uploads/default/2a3d26f8e9aa7de9aad64d4afcb372c4797f0447" title="微信图片_20211112191122"><img src="https://discuss.pytorch.org/uploads/default/optimized/3X/2/a/2a3d26f8e9aa7de9aad64d4afcb372c4797f0447_2_690x377.png" alt="微信图片_20211112191122" data-base62-sha1="61F4s4zAi7WP2pWmZipfa4udG6P" width="690" height="377" srcset="https://discuss.pytorch.org/uploads/default/optimized/3X/2/a/2a3d26f8e9aa7de9aad64d4afcb372c4797f0447_2_690x377.png, https://discuss.pytorch.org/uploads/default/optimized/3X/2/a/2a3d26f8e9aa7de9aad64d4afcb372c4797f0447_2_1035x565.png 1.5x, https://discuss.pytorch.org/uploads/default/optimized/3X/2/a/2a3d26f8e9aa7de9aad64d4afcb372c4797f0447_2_1380x754.png 2x" data-dominant-color="2D436B"><div class="meta"><svg class="fa d-icon d-icon-far-image svg-icon" aria-hidden="true"><use href="#far-image"></use></svg><span class="filename">微信图片_20211112191122</span><span class="informations">1920×1051 198 KB</span><svg class="fa d-icon d-icon-discourse-expand svg-icon" aria-hidden="true"><use href="#discourse-expand"></use></svg></div></a></div></p>

ptrblck: <p>Based on the error message it seems as if you might be trying to read an invalid file.<br>
Make sure the file really exists in the specified path and verify that you can load it properly (it could be broken due to a failed download).</p>
<p>PS: you can post code snippets by wrapping them into three backticks ```, which makes debugging easier <img src="https://discuss.pytorch.org/images/emoji/apple/wink.png?v=10" title=":wink:" class="emoji" alt=":wink:"></p>

lbs: <p>Thank you for your answer. I am sure that the 793th picture exists and can be called.</p>
<p><div class="lightbox-wrapper"><a class="lightbox" href="https://discuss.pytorch.org/uploads/default/original/3X/b/3/b3d0239c767753d5f3e77827c40e068675793a87.png" data-download-href="https://discuss.pytorch.org/uploads/default/b3d0239c767753d5f3e77827c40e068675793a87" title="微信图片_20211113212907"><img src="https://discuss.pytorch.org/uploads/default/optimized/3X/b/3/b3d0239c767753d5f3e77827c40e068675793a87_2_690x313.png" alt="微信图片_20211113212907" data-base62-sha1="pEHoZRajjZVOlDKFSO2AnUozywn" width="690" height="313" srcset="https://discuss.pytorch.org/uploads/default/optimized/3X/b/3/b3d0239c767753d5f3e77827c40e068675793a87_2_690x313.png, https://discuss.pytorch.org/uploads/default/optimized/3X/b/3/b3d0239c767753d5f3e77827c40e068675793a87_2_1035x469.png 1.5x, https://discuss.pytorch.org/uploads/default/optimized/3X/b/3/b3d0239c767753d5f3e77827c40e068675793a87_2_1380x626.png 2x" data-dominant-color="303030"><div class="meta"><svg class="fa d-icon d-icon-far-image svg-icon" aria-hidden="true"><use href="#far-image"></use></svg><span class="filename">微信图片_20211113212907</span><span class="informations">1847×840 118 KB</span><svg class="fa d-icon d-icon-discourse-expand svg-icon" aria-hidden="true"><use href="#discourse-expand"></use></svg></div></a></div></p>

lbs: <p><div class="lightbox-wrapper"><a class="lightbox" href="https://discuss.pytorch.org/uploads/default/original/3X/f/9/f9f3c1101eff310d7fd5469bcf892db4cc54e57d.png" data-download-href="https://discuss.pytorch.org/uploads/default/f9f3c1101eff310d7fd5469bcf892db4cc54e57d" title="微信图片_20211113212900"><img src="https://discuss.pytorch.org/uploads/default/optimized/3X/f/9/f9f3c1101eff310d7fd5469bcf892db4cc54e57d_2_690x303.png" alt="微信图片_20211113212900" data-base62-sha1="zFb87A1ysl228k93kgFZskl76q1" width="690" height="303" srcset="https://discuss.pytorch.org/uploads/default/optimized/3X/f/9/f9f3c1101eff310d7fd5469bcf892db4cc54e57d_2_690x303.png, https://discuss.pytorch.org/uploads/default/optimized/3X/f/9/f9f3c1101eff310d7fd5469bcf892db4cc54e57d_2_1035x454.png 1.5x, https://discuss.pytorch.org/uploads/default/optimized/3X/f/9/f9f3c1101eff310d7fd5469bcf892db4cc54e57d_2_1380x606.png 2x" data-dominant-color="303030"><div class="meta"><svg class="fa d-icon d-icon-far-image svg-icon" aria-hidden="true"><use href="#far-image"></use></svg><span class="filename">微信图片_20211113212900</span><span class="informations">1853×815 110 KB</span><svg class="fa d-icon d-icon-discourse-expand svg-icon" aria-hidden="true"><use href="#discourse-expand"></use></svg></div></a></div></p>