Added the precise computation intermediate results in showFeatureRepresentation output

MLP/include/MLP.hpp

@@ -167,6 +167,12 @@ class MLP
 
   public :
 
+  /// @brief Convert a dynet expression to a string (usefull for debug purposes)
+  ///
+  /// @param expr The expression to convert.
+  ///
+  /// @return A string representing the expression.
+  static std::string expression2str(dynet::Expression & expr);
   /// @brief initialize a new untrained MLP from a desired topology.
   ///
   /// topology example for 2 hidden layers : (150,RELU,0.3)(50,ELU,0.2)\n

MLP/src/MLP.cpp

@@ -247,9 +247,19 @@ dynet::Expression MLP::featValue2Expression(dynet::ComputationGraph & cg, const
 
 dynet::Expression MLP::run(dynet::ComputationGraph & cg, dynet::Expression x)
 {
+  static std::vector< std::pair<std::string,dynet::Expression> > exprForDebug;
+
   // Expression for the current hidden state
   dynet::Expression h_cur = x;
 
+  if (ProgramParameters::showFeatureRepresentation)
+  {
+    for (unsigned int i = 0; i < 81; i++)
+      fprintf(stderr, "%s", i == 80 ? "\n" : "-");
+    exprForDebug.clear();
+    exprForDebug.emplace_back("Input layer", h_cur);
+  }
+
   for(unsigned int l = 0; l < layers.size(); l++)
   {
     // Initialize parameters in computation graph
@@ -275,9 +285,25 @@ dynet::Expression MLP::run(dynet::ComputationGraph & cg, dynet::Expression x)
       h_dropped = h;
     }
 
+    if (ProgramParameters::showFeatureRepresentation)
+    {
+      exprForDebug.emplace_back("Result of h = h*W_" + std::to_string(l) + " + b_" + std::to_string(l), a);
+      exprForDebug.emplace_back("Result of h = a_" + std::to_string(l) + "(h)", h);
+      exprForDebug.emplace_back("Result of h = dropout_" + std::to_string(l) + "(h)", h_dropped);
+    }
+
     h_cur = h_dropped;
   }
 
+  if (ProgramParameters::showFeatureRepresentation)
+  {
+    cg.forward(h_cur);
+    for (auto & it : exprForDebug)
+      fprintf(stderr, "%s (dimension=%lu) :\n%s\n", it.first.c_str(), dynet::as_vector(it.second.value()).size(), expression2str(it.second).c_str());
+    for (unsigned int i = 0; i < 81; i++)
+      fprintf(stderr, "%s", i == 80 ? "\n" : "-");
+  }
+
   return h_cur;
 }
 
@@ -413,3 +439,19 @@ dynet::ParameterCollection & MLP::getModel()
   return model;
 }
 
+std::string MLP::expression2str(dynet::Expression & expr)
+{
+  std::string result = "<";
+
+  auto elem = dynet::as_vector(expr.value());
+
+  for (auto & f : elem)
+    result += float2str(f, "%f") + " ";
+
+  result.pop_back();
+
+  result += ">";
+
+  return result;
+}
+