CONV backward

[weiyanlin117]

test passed only support weights gradient and output gradient, on bias gradient yet, Since I notice pytorch doesn't implement bias gradient, I treat bias gradient as optional? I can spend time if it is needed.

[liuliu]

Have you tried NHWC layout (with weights potentially in NCHW layout)?

[weiyanlin117]

[weiyanlin117]

NCHW works as same as previous

[liuliu]

Probably need a regen.

[weiyanlin117]

[weiyanlin117]

normal test passed. commented out dbias test passed.