better check of input

source/tensor/core/movement/CopyValues.cpp

@@ -35,16 +35,19 @@ copy s to t
 */
 void _CopyValues(const XTensor * s, XTensor * t, XStream * stream)
 {
-    CheckNTErrors((s != NULL && t != NULL), "The input tensor and output tensor must be nonempty!");
-    CheckNTErrors((s->data != NULL), "Cannot copy an empty data array!");
-    CheckNTErrors((t->data != NULL), "Cannot copy to an empty data array!");
-    CheckNTErrors((s->unitNum == t->unitNum), "Unmatched data item number!");
+    if(s->data == NULL && t->data == NULL)
+        return;
+
+    CheckNTErrors(s != NULL && t != NULL, "The input tensor and output tensor must be nonempty!");
+    CheckNTErrors(s->data != NULL, "Cannot copy an empty data array!");
+    CheckNTErrors(t->data != NULL, "Cannot copy to an empty data array!");
+    CheckNTErrors(s->unitNum == t->unitNum, "Unmatched data item number!");
 
     if ((s->dataType == X_FLOAT16 && t->dataType == X_FLOAT) ||
         (s->dataType == X_FLOAT && t->dataType == X_FLOAT16)) {
-        CheckNTErrors(((s->devID < 0 && t->devID < 0) || s->devID == t->devID),
+        CheckNTErrors((s->devID < 0 && t->devID < 0) || s->devID == t->devID,
                        "The code must be run on the same device!");
-        CheckNTErrors((s->isSparse || t->isSparse), "TODO!");
+        CheckNTErrors(s->isSparse || t->isSparse, "TODO!");
         ConvertDataType(s->devID, s->data, s->dataType, t->data, t->dataType, s->unitNum);
     }
 
@@ -81,8 +84,12 @@ copy s to t
 */
 void _CopyValues(const XTensor * s, const int sBeg, const int sLen, XTensor * t, const int tBeg, XStream * stream)
 {
+    if(s->data == NULL && t->data == NULL)
+        return;
+
     CheckNTErrors(s != NULL && t != NULL, "The input tensor and output tensor must be nonempty!");
-    CheckNTErrors(s->data != NULL && t->data != NULL, "Cannot copy an empty data array!");
+    CheckNTErrors(s->data != NULL, "Cannot copy an empty data array!");
+    CheckNTErrors(t->data != NULL, "Cannot copy to an empty data array!");
     CheckNTErrors(s->unitSize == t->unitSize, "The input tensors must be of the same unit size!");
     CheckNTErrors(s->order > sBeg && sBeg >= 0 && sLen <= s->unitNum, "Wrong segment on the source side");
     CheckNTErrors(t->order > tBeg && tBeg >= 0, "Wrong segment on the target side");