[GitHub] piiswrong commented on a change in pull request #9029: Update ndarray binary ops to use kernel launch instead of mshadow operations

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

piiswrong commented on a change in pull request #9029: Update ndarray binary ops to use kernel launch instead of mshadow operations
URL: https://github.com/apache/incubator-mxnet/pull/9029#discussion_r165178480
 
 

 ##########
 File path: src/ndarray/ndarray_function-inl.h
 ##########
 @@ -433,6 +442,27 @@ void EvalBroadcast<DEVICE>(TBlob const& src, TBlob* ret, int size, RunContext ct
   out = mshadow::expr::broadcast_with_axis(in, 0, size);
 }
 
+/*! \brief Minimum of three */
+MSHADOW_XINLINE size_t minthree(const size_t a, const size_t b, const size_t c) {
+  return a < b ? (a < c ? a : c) : (b < c ? b : c);
+}
+
+template<typename OP, typename xpu>
+void BinaryOpKernelLaunch(mshadow::Stream<xpu>* s, const TBlob& lhs, const TBlob& rhs, TBlob *out) {
+  using namespace op::mxnet_op;
+  using namespace mshadow;
+  MSHADOW_TYPE_SWITCH(out->type_flag_, DType, {
+    const size_t size = (minthree(out->Size(), lhs.Size(), rhs.Size())
+                         + DataType<DType>::kLanes - 1)
+                        / DataType<DType>::kLanes;
 
 Review comment:
   why do you need to calc size like this?

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