Handle ograd_stype='row_sparse' for square_sum backward#143

Merged

eric-haibin-lin merged 2 commits intoeric-haibin-lin:sparsefrom reminisce:backward_kernel_square_sum

Aug 3, 2017

Commits on Aug 3, 2017

Add one kernel for square_sum backward pass to take rsp ograd
reminisce
committed
Add kNullOp and change to use type_assign in infer stype fallback
reminisce
committed