[GitHub] [incubator-mxnet] hgt312 commented on a change in pull request #18250: fix mixed type backward

[GitBox <gi...@apache.org>]

hgt312 commented on a change in pull request #18250:
URL: https://github.com/apache/incubator-mxnet/pull/18250#discussion_r420643035



##########
File path: src/operator/mshadow_op.h
##########
@@ -746,6 +746,10 @@ MXNET_BINARY_MATH_OP_NC(minus_sign, a - b > DType(0) ? DType(1) : -DType(1));
 
 MXNET_BINARY_MATH_OP(rminus, b - a);
 
+MXNET_BINARY_MATH_OP_NC(self_grad, 1);
+
+MXNET_BINARY_MATH_OP_NC(minus_rgrad, -1);
+

Review comment:
       Could use better func name? Like `posone`, `negone`?

##########
File path: src/operator/numpy/np_elemwise_broadcast_op.cc
##########
@@ -115,7 +115,22 @@ MXNET_OPERATOR_REGISTER_NP_BINARY_MIXED_PRECISION(_npi_add)
   "FCompute<cpu>",
   NumpyBinaryBroadcastComputeWithBool<cpu, op::mshadow_op::plus>)
 #endif
-.set_attr<nnvm::FGradient>("FGradient", ElemwiseGradUseNone{"_backward_broadcast_add"});
+.set_attr<nnvm::FGradient>("FGradient", ElemwiseGradUseIn{"_backward_npi_broadcast_add"});
+
+NNVM_REGISTER_OP(_backward_npi_broadcast_add)
+.set_num_inputs(3)
+.set_num_outputs(2)
+.set_attr<nnvm::TIsBackward>("TIsBackward", true)
+.set_attr<nnvm::FInplaceOption>("FInplaceOption",
+  [](const NodeAttrs& attrs){
+    return std::vector<std::pair<int, int> >{{0, 1}};

Review comment:
       ```suggestion
       return std::vector<std::pair<int, int> >{{0, 0}, {0, 1}};
   ```




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