improve the way of using buf tensors

source/network/XBackwardShape.cpp

@@ -268,10 +268,12 @@ void XShapeGrad::GradSplit(XTensor * node, bool isEfficient)
     /* if the tensor is used somewhere else, we need another SUM
        for gradient accumulation */
     else{
-        XTensor inputGradTMP(input);
+        XTensor * inputGradTMP = NewTensorBuf(input, input->devID, input->mem);
 
-        _Merge(node->grad, &inputGradTMP, whereToSplit + 1, 0);
-        _Sum(input->grad, &inputGradTMP, input->grad);
+        _Merge(node->grad, inputGradTMP, whereToSplit + 1, 0);
+        _Sum(input->grad, inputGradTMP, input->grad);
+        
+        DelTensorBuf(inputGradTMP);
     }
 
     node->visitMark = NODE_FINISHED;
@@ -347,10 +349,12 @@ void XShapeGrad::GradSplitListPost(XTensor * node, bool isEfficient)
        somewhere else, we need another SUM for gradient 
        accumulation */
     else{
-        XTensor nodeGradTMP(node);
+        XTensor * nodeGradTMP = NewTensorBuf(node, node->devID, node->mem);
 
-        _Merge(&splits, &nodeGradTMP, whereToSplit + 1);
-        _Sum(node->grad, &nodeGradTMP, node->grad);
+        _Merge(&splits, nodeGradTMP, whereToSplit + 1);
+        _Sum(node->grad, nodeGradTMP, node->grad);
+        
+        DelTensorBuf(nodeGradTMP);
     }
 }
 
@@ -378,8 +382,13 @@ void XShapeGrad::GradUnsqueeze(XTensor * node, bool isEfficient)
 
     CheckNTErrors(dSize == output->GetDim(dim), "Wrong dim size for UNSQUEEZE!");
     CheckNTErrors(output->unitNum = input->unitNum * dSize, "Wrong tensor size!");
-
-    _ReduceSum(output->grad, input->grad, dim);
+    
+    XTensor * g = NewTensorBuf(input->grad, input->devID, input->mem);
+    
+    _ReduceSum(output->grad, g, dim);
+    _Sum(input->grad, g, input->grad);
+    
+    DelTensorBuf(g);
 
     node->visitMark = NODE_FINISHED;
 }
@@ -401,7 +410,7 @@ void XShapeGrad::GradTranspose(XTensor * node, bool isEfficient)
 
     XTensor * output = node;
     XTensor * input = income.tails[0];
-    XTensor * b = NewTensor(input);
+    XTensor * b = NewTensorBuf(input, input->devID, input->mem);
     XNoder::MakeGrad(input);
 
     int i = income.GetParamInt(0);
@@ -412,10 +421,12 @@ void XShapeGrad::GradTranspose(XTensor * node, bool isEfficient)
 
     _Transpose(output->grad, b, i, j);
     _Sum(input->grad, b, input->grad);
+    
+    DelTensorBuf(b);
 
     node->visitMark = NODE_FINISHED;
 
     delete b;
 }
 
-}
\ No newline at end of file
+}