fix the bug when we kill a node whose parent node is still alive

source/tensor/XTensor.cpp

@@ -193,7 +193,7 @@ XTensor::~XTensor()
        the connectivity of the graph. To kill memory
        the connectivity of the graph. To kill memory
        leak, we release the data of the new tensor
        leak, we release the data of the new tensor
        when its parent is deleted (see ClearIncoming). */
        when its parent is deleted (see ClearIncoming). */
-    if(isTmp && outgo.tailNum > 0){
+    if(outgo.tailNum > 0){
         int dims[MAX_TENSOR_DIM_NUM];
         int dims[MAX_TENSOR_DIM_NUM];
         memcpy(dims, dimSize, order * sizeof(int));
         memcpy(dims, dimSize, order * sizeof(int));
         dims[0] = -dims[0];
         dims[0] = -dims[0];
@@ -285,6 +285,27 @@ void XTensor::ShallowCopy(const XTensor &tensor)
 /* overloading of the equal-sign */
 /* overloading of the equal-sign */
 XTensor& XTensor::operator= (const XTensor& tensor)
 XTensor& XTensor::operator= (const XTensor& tensor)
 {
 {
+    /* we must make a hard copy of the tensor if it is the input 
+       of another node. */
+    if(outgo.tailNum > 0){
+        int dims[MAX_TENSOR_DIM_NUM];
+        memcpy(dims, dimSize, order * sizeof(int));
+        dims[0] = -dims[0];
+        
+        XTensor * newTensor = new XTensor(order, dims, dataType, denseRatio, devID, mem);
+        newTensor->SetTMP();
+        newTensor->data = data;
+        newTensor->dataHost = dataHost;
+        
+        XLink::Replace(this, newTensor);
+        XLink::ClearOutgoing(this);
+        XLink::ClearIncoming(this);
+        newTensor->ShallowCopy(this);
+
+        data = NULL;
+        dataHost = NULL;
+    }
+
     /* hard copy of the data array */
     /* hard copy of the data array */
     int size = unitNum * unitSize;
     int size = unitNum * unitSize;
     if( isInit && !isSparse && !tensor.isSparse &&
     if( isInit && !isSparse && !tensor.isSparse &&