title: Pytorch RuntimeError: mat1 dim 1 must match mat2 dim 0
body: <p>I tried to run a NeRF Neural Radiance Fields PyTorch program on Google Colab, and I got an error(<code>RuntimeError: mat1 dim 1 must match mat2 dim 0</code>) at line 113 in the last cell(below Run training / validation cell). It seems like the source code is missing two arguments in <code>nerf_forward_pass</code> function, the <code>nerf_forward_pass</code> function has 19 arguments and it inputs only 17, but I still got the same error after adding the two missing arguments.</p>
  <p>I contacted the author, he said he enabled the public editing of his Google Colab, so most likely someone mistakenly edited it and made it not runnable. Recently the author is unavailable to come back and fix it. If we want the author to fix, we have to wait for long.</p>
  <p>Can anyone provide solutions?</p>
  <p>Google Colab: <a href="https://colab.research.google.com/drive/1L6QExI2lw5xhJ-MLlIwpbgf7rxW7fcz3" rel="nofollow noreferrer">https://colab.research.google.com/drive/1L6QExI2lw5xhJ-MLlIwpbgf7rxW7fcz3</a>
  Github: <a href="https://github.com/krrish94/nerf-pytorch" rel="nofollow noreferrer">https://github.com/krrish94/nerf-pytorch</a></p>