implement the left-constant overloading and TtypeAs function

source/tensor/XTensor.cpp

@@ -704,6 +704,12 @@ void XTensor::ReshapeMerged(const int i, const int j)
     Reshape(order - 1, dims);
 }
 
+/* return a tensor that datatype is same as the special tensor */
+XTensor XTensor::TypeAs(const XTensor input)
+{
+    return ConvertDataType(*this, input.dataType);
+}
+
 /* get the number of items in the data array */
 int XTensor::GetSize() const
 {
@@ -3047,4 +3053,28 @@ void DelTensorBuf(XTensor * tensor)
     delete tensor;
 }
 
+/* overloading of the plus-sign */
+XTensor operator+ (const DTYPE shift, const XTensor &tensor) 
+{
+    return ScaleAndShift(tensor, 1, shift);
+}
+
+/* overloading of the minus-sign */
+XTensor  operator- (const DTYPE shift, const XTensor &tensor)
+{
+    return ScaleAndShift(tensor, 1, -shift);
+}
+
+/* overloading of the multiply-sign */
+XTensor  operator* (const DTYPE scale, const XTensor &tensor)
+{
+    return ScaleAndShift(tensor, scale, 0);
+}
+
+/* overloading of the division-sign */
+XTensor  operator/ (const DTYPE scale, const XTensor &tensor)
+{
+    return ScaleAndShift(tensor, (DTYPE)1/scale, 0);
+}
+
 } /* end of the nts (NiuTrans.Tensor) namespace */

source/tensor/XTensor.h

@@ -283,6 +283,9 @@ public:
     /* reshape the tensor by merging two consecutive dimensions */
     void ReshapeMerged(const int i, const int j = -1);
 
+    /* return a tensor that datatype is same as the special tensor */
+    XTensor TypeAs(const XTensor input);
+
     /* get the number of items in the data array */
     int GetSize() const;
 
@@ -599,6 +602,18 @@ void DelTensor(XTensor * tensor);
 /* free the data space of a given tensor (on the buffer) */
 void DelTensorBuf(XTensor * tensor);
 
+/* overloading of the plus-sign */
+XTensor  operator+ (const DTYPE shift, const XTensor &tensor);
+
+/* overloading of the minus-sign */
+XTensor  operator- (const DTYPE shift, const XTensor &tensor);
+
+/* overloading of the multiply-sign */
+XTensor  operator* (const DTYPE scale, const XTensor &tensor);
+
+/* overloading of the division-sign */
+XTensor  operator/ (const DTYPE scale, const XTensor &tensor);
+
 } /* end of the nts (NiuTrans.Tensor) namespace */
 
 #endif