Modified ResizeOutputLayer method in nnet-nnet.cc to accommodate networks with FixedScaleComponents

src/nnet2/nnet-component.cc

@@ -1407,6 +1407,20 @@ Component *AffineComponent::CollapseWithNext(
   return ans;
 }
 
+Component *AffineComponent::CollapseWithNext(
+    const FixedScaleComponent &next_component) const {
+  KALDI_ASSERT(this->OutputDim() == next_component.InputDim());
+  AffineComponent *ans =
+      dynamic_cast<AffineComponent*>(this->Copy());
+  KALDI_ASSERT(ans != NULL);
+  ans->linear_params_.MulRowsVec(next_component.scales_);
+  ans->bias_params_.MulElements(next_component.scales_);
+
+  return ans;
+}
+
+
+
 Component *AffineComponent::CollapseWithPrevious(
     const FixedAffineComponent &prev_component) const {
   // If at least one was non-updatable, make the whole non-updatable.

src/nnet2/nnet-component.h

@@ -709,6 +709,7 @@ class ScaleComponent: public Component {
 
 class SumGroupComponent; // Forward declaration.
 class AffineComponent; // Forward declaration.
+class FixedScaleComponent; // Forward declaration.
 
 class SoftmaxComponent: public NonlinearComponent {
  public:
@@ -803,6 +804,7 @@ class AffineComponent: public UpdatableComponent {
   // FixedLinearComponent yet.
   Component *CollapseWithNext(const AffineComponent &next) const ;
   Component *CollapseWithNext(const FixedAffineComponent &next) const;
+  Component *CollapseWithNext(const FixedScaleComponent &next) const;
   Component *CollapseWithPrevious(const FixedAffineComponent &prev) const;
 
   virtual std::string Info() const;
@@ -1473,6 +1475,7 @@ class FixedScaleComponent: public Component {
   virtual void Write(std::ostream &os, bool binary) const;
 
  protected:
+  friend class AffineComponent; // necessary for collapse
   CuVector<BaseFloat> scales_;  
   KALDI_DISALLOW_COPY_AND_ASSIGN(FixedScaleComponent);
 };

src/nnet2/nnet-nnet.cc

@@ -372,16 +372,43 @@ void Nnet::ResizeOutputLayer(int32 new_num_pdfs) {
   if ((sc = dynamic_cast<SoftmaxComponent*>(components_[nc - 1])) == NULL)
     KALDI_ERR << "Expected last component to be SoftmaxComponent.";
 
+  // check if nc-1 has a FixedScaleComponent
+  bool has_fixed_scale_component = false;
+  int32 fixed_scale_component_index = -1;
+  int32 final_affine_component_index = nc - 2;
+  int32 softmax_component_index = nc - 1;
+  FixedScaleComponent *fsc =
+      dynamic_cast<FixedScaleComponent*>(
+          components_[final_affine_component_index]);
+  if (fsc != NULL)  {
+    has_fixed_scale_component = true; 
+    fixed_scale_component_index = nc - 2;
+    final_affine_component_index = nc - 3;
+  }
+    
   // note: it could be child class of AffineComponent.
-  AffineComponent *ac = dynamic_cast<AffineComponent*>(components_[nc - 2]);
+  AffineComponent *ac = dynamic_cast<AffineComponent*>(
+      components_[final_affine_component_index]);
   if (ac == NULL)
     KALDI_ERR << "Network doesn't have expected structure (didn't find final "
               << "AffineComponent).";
-  
+  if (has_fixed_scale_component)  {
+    // collapse the fixed_scale_component with the affine_component before it
+    AffineComponent *ac_new = dynamic_cast<AffineComponent*>(ac->CollapseWithNext(*fsc));
+    KALDI_ASSERT(ac_new != NULL);
+    delete fsc;
+    delete ac;
+    components_.erase(components_.begin() + fixed_scale_component_index,
+                      components_.begin() + (fixed_scale_component_index + 1));
+    components_[final_affine_component_index] = ac_new;
+    ac = ac_new;
+    softmax_component_index = softmax_component_index - 1;
+  }
+   
   ac->Resize(ac->InputDim(), new_num_pdfs);
   // Remove the softmax component, and replace it with a new one
-  delete components_[nc - 1];
-  components_[nc - 1] = new SoftmaxComponent(new_num_pdfs);
+  delete components_[softmax_component_index];
+  components_[softmax_component_index] = new SoftmaxComponent(new_num_pdfs);
   this->Check();
 }