Invalid argument 2: 3D or 4D input tensor expected but got: [32 x 784]

[JeffreyYH]

Hi Hugh, thanks for this nice software, when I run the example code of MNIST, it shows the following error,

Connected to pydev debugger (build 171.4694.67)
$ Invalid argument 2: 3D or 4D input tensor expected but got: [32 x 784] at /tmp/luarocks_nn-scm-1-8028/nn/lib/THNN/generic/SpatialConvolutionMM.c:33

How to deal with it

[hughperkins]

the error message means it expects a tensor of dimension 32 * 28 * 28, rather than 32 * 784.