Why sparse convolutional inference time is longer

[jiaerwang0328]

run python test_timeit.py: compare time with nn.Conv3d() nn.Conv3D() forward time is :0.000066 SparseConv3d() forward time is :0.001239 nn.Conv3D() backward time is :0.000870 SparseConv3d() backward time is :0.001930

[ColdCodeCool]

maybe your sparsity of test case is small, like below 50%, as far as I concerned, the sparse version of Conv performs better when the sparsity of feature is big like above 70%. Hope the author will explain this