[GitHub] rahul003 commented on a change in pull request #11356: [MXNET-560][WIP] Add temperature parameter in Softmax and SoftmaxOutput operator

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rahul003 commented on a change in pull request #11356: [MXNET-560][WIP] Add temperature parameter in Softmax and SoftmaxOutput operator
URL: https://github.com/apache/incubator-mxnet/pull/11356#discussion_r197275632
 
 

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 File path: src/operator/nn/softmax-inl.h
 ##########
 @@ -145,23 +155,36 @@ __global__ void softmax_compute_kernel(DType *in, DType *out, index_t M, int axi
   __syncthreads();
 
   red::sum::SetInitValue(smem[x]);
-  for (index_t i = x; i < M; i += x_size) {
-    red::sum::Reduce(smem[x], static_cast<DType>(expf(in[base + i*sa] - smax)));
+  if (temperature == 1.0) {
+    for (index_t i = x; i < M; i += x_size) {
+      red::sum::Reduce(smem[x], static_cast<DType>(expf(in[base + i*sa] - smax)));
+    }
+  } else {
+    for (index_t i = x; i < M; i += x_size) {
+      red::sum::Reduce(smem[x], static_cast<DType>(expf((in[base + i*sa] - smax)/temperature)));
+    }
   }
+
   __syncthreads();
   cuda::Reduce1D<red::sum, x_bits>(smem);
   __syncthreads();
   DType ssum = smem[0];
   __syncthreads();
 
-  for (index_t i = x; i < M; i += x_size) {
-    out[base + i*sa] = OP::Map(in[base + i*sa] - smax, ssum);
+  if (temperature == 1.0) {
 
 Review comment:
   I'd suggest removing the if condition and merging these two cases, since it's perfectly okay to use the second equation for temperature=1. The if condition within this kernel can cause branching on CPU and affect performance

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