Merge branch 'prelu-bug' into 'master'

Fix prelu benchmark bug.

See merge request !264

mace/kernels/activation.h

@@ -116,7 +116,8 @@ class ActivationFunctor {
     const T *input_ptr = input->data<T>();
     T *output_ptr = output->mutable_data<T>();
     if (activation_ == PRELU) {
-      const T *alpha_ptr = alpha == nullptr ? nullptr : alpha->data<T>();
+      MACE_CHECK(alpha != nullptr) << "PReLU's alpha parameter shouldn't be null";
+      const T *alpha_ptr = alpha->data<T>();
       PReLUActivation(input_ptr, output->size(), input->dim(3), alpha_ptr, output_ptr); 
     } else {
       DoActivation(input_ptr, output_ptr, output->size(), activation_, relux_max_limit_);

mace/ops/activation_benchmark.cc

@@ -139,23 +139,26 @@ static void PreluBenchmark(
 
   // Add input data
   net.AddRandomInput<D, float>("Input", {batch, height, width, channels});
+  net.AddRandomInput<D, float>("Alpha", {channels});
 
   if (D == DeviceType::OPENCL) {
     BufferToImage<D, float>(net, "Input", "InputImage",
                             kernels::BufferType::IN_OUT_CHANNEL);
+    BufferToImage<D, float>(net, "Alpha", "AlphaImage",
+                            kernels::BufferType::ARGUMENT);
 
     OpDefBuilder("Activation", "PreluBM")
         .Input("InputImage")
+        .Input("AlphaImage")
         .Output("Output")
         .AddStringArg("activation", "PRELU")
-        .AddFloatArg("alpha", 2.0)
         .Finalize(net.NewOperatorDef());
   } else {
     OpDefBuilder("Activation", "PreluBM")
         .Input("Input")
+        .Input("Alpha")
         .Output("Output")
         .AddStringArg("activation", "PRELU")
-        .AddFloatArg("alpha", 2.0)
         .Finalize(net.NewOperatorDef());
   }