backward propagation for MatrixMul

source/network/Main.cpp

@@ -55,9 +55,9 @@ int main( int argc, const char ** argv )
     b.SetZeroAll();
     c.SetZeroAll();
 
-    SetDataFixed(a, 1.0F);
-    a.Set2D(3.0F, 1, 0);
-    a.Set2D(4.0F, 1, 1);
+    SetDataFixed(a, 0.1F);
+    a.Set2D(0.3F, 1, 0);
+    a.Set2D(0.4F, 1, 1);
 
     b = a + a;
     c = HTanH(MMul(a, b));

source/network/XBackwardMath.cpp

@@ -116,10 +116,13 @@ void XMathGrad::GradMatrixMul(XTensor * node)
 {
     XLink &income = node->income;
     CheckNTErrors(income.tailNum == 2, "Wrong input tensor number for MULTIPLY!");
+    CheckNTErrors(income.paramNum == 3, "Wrong parameter number for MULTIPLY!");
 
     XTensor * a = income.tails[0]; 
     XTensor * b = income.tails[1];
-    DTYPE alpha = income.GetParam(0);
+    MATRIX_TRANS_TYPE transA = income.GetParamTrans(0);
+    MATRIX_TRANS_TYPE transB = income.GetParamTrans(1);
+    DTYPE alpha = income.GetParam(2);
 
     XNoder::MakeGrad(a);
     XNoder::MakeGrad(b);
@@ -128,11 +131,45 @@ void XMathGrad::GradMatrixMul(XTensor * node)
     XTensor * deda = a->grad;
     XTensor * dedb = b->grad;
     
+    /* c = a * b * \alpha */
+    if(transA == X_NOTRANS && transB == X_NOTRANS){
+
+        /* dE/da = dE/dc * b^T * \alpha */
+        _MatrixMul(dedc, X_NOTRANS, b, X_TRANS, deda, alpha);
+
+        /* dE/db = a^T * dE/dc * \alpha */
+        _MatrixMul(a, X_TRANS, dedc, X_NOTRANS, dedb, alpha);
+    }
+    
+    /* c = a^T * b * \alpha */
+    else if(transA == X_TRANS && transB == X_NOTRANS){
+        
         /* dE/da = dE/dc * b^T * \alpha */
         _MatrixMul(dedc, X_NOTRANS, b, X_TRANS, deda, alpha);
         
+        /* dE/db = a * dE/dc * \alpha */
+        _MatrixMul(a, X_NOTRANS, dedc, X_NOTRANS, dedb, alpha);
+    }
+    
+    /* c = a * b^T * \alpha */
+    else if(transA == X_NOTRANS && transB == X_TRANS){
+        
+        /* dE/da = dE/dc * b * \alpha */
+        _MatrixMul(dedc, X_NOTRANS, b, X_NOTRANS, deda, alpha);
+        
         /* dE/db = a^T * dE/dc * \alpha */
         _MatrixMul(a, X_TRANS, dedc, X_NOTRANS, dedb, alpha);
+    }
+    
+    /* c = a^T * b^T * \alpha */
+    else if(transA == X_TRANS && transB == X_TRANS){
+        
+        /* dE/da = dE/dc * b * \alpha */
+        _MatrixMul(dedc, X_NOTRANS, b, X_NOTRANS, deda, alpha);
+        
+        /* dE/db = a * dE/dc * \alpha */
+        _MatrixMul(a, X_NOTRANS, dedc, X_NOTRANS, dedb, alpha);
+    }
 }
 
 }

source/tensor/XLink.cpp

@@ -240,7 +240,8 @@ void XLink::AddParam(void * param, int size)
 
 /* 
 get a paramter in default type 
->> i - id the of the parameter
+>> i - id of the parameter
+<< return - the parameter in default type
 */
 DTYPE XLink::GetParam(int i)
 {
@@ -251,7 +252,8 @@ DTYPE XLink::GetParam(int i)
 
 /* 
 get a paramter in integer 
->> i - id the of the parameter
+>> i - id of the parameter
+<< return - the parameter in integer
 */
 int XLink::GetParamInt(int i)
 {
@@ -261,6 +263,18 @@ int XLink::GetParamInt(int i)
 }
     
 /*
+get a parameter in MATRIX_TRANS_TYPE
+>> i - id of the parameter
+<< return - the parameter in MATRIX_TRANS_TYPE
+*/
+MATRIX_TRANS_TYPE XLink::GetParamTrans(int i)
+{
+    CheckNTErrors(params != NULL, "parameter array cannot be empty!");
+    char * p = (char*)params + i * paramSize;
+    return *(MATRIX_TRANS_TYPE*)p;
+}
+
+/* 
 create a hyperedge with two input tensors and a output tensor 
 >> t1 - a tail tensor
 >> t2 - another tail tensor

source/tensor/XLink.h

@@ -128,6 +128,9 @@ struct XLink
     /* get a paramter in integer */
     int GetParamInt(int i);
     
+    /* get a parameter in MATRIX_TRANS_TYPE */
+    MATRIX_TRANS_TYPE GetParamTrans(int i);
+
     /* create a hyper edge with two input tensors and a output tensor */
     static
     void MakeLink(const XTensor * t1, const XTensor * t2, XTensor * h, int id);