Bug fixed.

Fix the bug in SumMe function which cannot handle the scalar tensor and broadcast case.

source/tensor/core/arithmetic/Sum.cpp

@@ -183,7 +183,25 @@ keep the result in the tensor a and return nothing
 */
 void SumMe(XTensor& a, const XTensor& b, DTYPE beta)
 {
-    _Sum(&a, &b, &a, beta);
+    if (b.order == 0){
+        DTYPE shift = b.Get0D() * beta;
+        _ScaleAndShift(&a, &a, 1.0F, shift);
+    }
+    else {
+        int n = GetBroadcastDimIndex(a, b);
+
+        if (n == -1) {
+            /* call _Sum function */
+            _Sum(&a, &b, &a, beta);
+        }
+        else if (n >= 0 && n < a.order) {
+            /* call _SumDim function */
+            _SumDim(&a, &b, &a, n, beta);
+        }
+        else {
+            ShowNTErrors("Something is wrong!");
+        }
+    }
 }
 
 /*