backward_numeric()

src/chainable.h

@@ -34,6 +34,8 @@ struct Chainable {
     virtual ~Chainable() { }
     virtual void forward() { }
     virtual void backward() { }
+    virtual void backward_numeric() { }
+
     virtual void check() { }
     virtual void init_dependent() { }
     virtual void set_zero_adjoint() { }

src/expression_graph.h

@@ -127,6 +127,19 @@ class ExpressionGraph {
         (*it)->backward();
     }
 
+    void backward_numeric() {
+      for(auto&& v : *stack_)
+        v->set_zero_adjoint();
+
+      typedef typename ChainableStack::reverse_iterator It;
+      stack_->back()->init_dependent();
+      for(It it = stack_->rbegin(); it != stack_->rend(); ++it) {
+    	  Chainable<Tensor> *chainable = *it;
+    	  //chainable->backward();
+    	  chainable->backward_numeric();
+      }
+    }
+
     /**
      * @brief Returns a string representing this expression graph in <code>graphviz</code> notation.
      *

src/node_operators.h

@@ -114,6 +114,10 @@ struct UnaryNodeOp : public Node {
     UnaryNodeOp(ChainPtr a, Args ...args)
     : Node(keywords::shape=a->shape(), //@TODO: Check keywords?
            args...), a_(a) {}
+
+    void backward_numeric() {
+  	  backward();
+    }
 };
 
 struct LogitNodeOp : public UnaryNodeOp {
@@ -289,7 +293,7 @@ struct NegNodeOp : public UnaryNodeOp {
   void backward() {
     Element(_1 += -_2, a_->grad(), adj_);
   }
-  
+
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"-\", style=\"filled\", fillcolor=\"yellow\"]" << std::endl;
@@ -308,6 +312,11 @@ struct BinaryNodeOp : public Node {
   template <typename ...Args>
   BinaryNodeOp(ChainPtr a, ChainPtr b, Args ...args)
    : Node(args...), a_(a), b_(b) {}
+
+  void backward_numeric() {
+	  backward();
+  }
+
 };
 
 /*** Matrix Product ***/
@@ -450,7 +459,7 @@ struct DivNodeOp : public BinaryNodeOp {
     Element(_1 -= _2 * _3 / (_4 * _4),
             b_->grad(), adj_, a_->val(), b_->val());
   }
-  
+
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"÷\", style=\"filled\", fillcolor=\"yellow\"]" << std::endl;
@@ -519,7 +528,8 @@ struct CrossEntropyNodeOp : public BinaryNodeOp {
   virtual std::string graphviz() {
     std::stringstream ss;
     ss << "\"" << this << "\" [shape=\"box\", label=\"cross_entropy\", style=\"filled\", fillcolor=\"yellow\"]" << std::endl;
-    ss << "\"" << a_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
+    ss << "\"" << a_ << "\" -> \"" << this << "\"" << std::endl;
+    ss << "\"" << b_ << "\" -> \"" << this << "\"" << std::endl << std::endl;
     return ss.str();
   };
 

src/test_nodes.cu

@@ -54,7 +54,8 @@ int main(int argc, char** argv)
 
   // train
   g.forward(batch_size);
-  g.backward();
+  //g.backward();
+  g.backward_numeric();
 
   std::cout << g.graphviz() << std::endl;
 
@@ -67,10 +68,4 @@ int main(int argc, char** argv)
   std::cerr << "outGrad=" << outGrad.Debug() << std::endl;
 
 
-  Tensor costTensor = cost.val();
-  std::cerr << "costTensor=" << costTensor.Debug() << std::endl;
-
-  Tensor costGrad = cost.grad();
-  std::cerr << "costGrad=" << costGrad.Debug() << std::endl;
-
 }