Bug fixed and clean the codes.

1. Fix the bug in SubMe function which cannot handle the scalar tensor and broadcast case.
2. Clean the codes.

source/tensor/core/arithmetic/Sub.cpp

@@ -63,9 +63,24 @@ keep the result in the tensor a and return nothing
 >> b - another tensor
 >> beta - the scaling factor
 */
-void SubMe(XTensor& a, const XTensor& b, DTYPE beta)
+void SubMe(XTensor & a, const XTensor & b, DTYPE beta)
 {
-    _Sub(&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 _Sub function */
+            _Sub(&a, &b, &a, beta);
+        else if (n >= 0 && n < a.order)
+            /* call _SumDim function to do the SubDim operation */
+            _SumDim(&a, &b, &a, n, -beta);
+        else
+            ShowNTErrors("Something is wrong!");
+    }
 }
 
 /*
@@ -77,7 +92,7 @@ make a new tensor c to keep the result and return it
 >> beta - the scaling factor
 << return - the result of tensor subtraction
 */
-XTensor Sub(const XTensor &a, const XTensor &b, DTYPE beta)
+XTensor Sub(const XTensor & a, const XTensor & b, DTYPE beta)
 {
     XTensor c(&a);
     c.SetTMPFlag();
@@ -125,7 +140,7 @@ tensor subtraction c = a - b * \beta
 >> c - where we put a-b*\beta. we save it in a if c is NULL
 >> beta - the scaling factor
 */
-void Sub(const XTensor &a, const XTensor &b, XTensor &c, DTYPE beta)
+void Sub(const XTensor & a, const XTensor & b, XTensor & c, DTYPE beta)
 {
     if (!c.isInit || !IsSameShaped(a, c)) {
         InitTensorV2(&c, &a);

source/tensor/core/arithmetic/Sum.cpp

@@ -181,7 +181,7 @@ keep the result in the tensor a and return nothing
 >> b - another tensor
 >> beta - the scaling factor
 */
-void SumMe(XTensor& a, const XTensor& b, DTYPE beta)
+void SumMe(XTensor & a, const XTensor & b, DTYPE beta)
 {
     if (b.order == 0){
         DTYPE shift = b.Get0D() * beta;
@@ -190,17 +190,14 @@ void SumMe(XTensor& a, const XTensor& b, DTYPE beta)
     else {
         int n = GetBroadcastDimIndex(a, b);
 
-        if (n == -1) {
+        if (n == -1)
             /* call _Sum function */
             _Sum(&a, &b, &a, beta);
-        }
-        else if (n >= 0 && n < a.order) {
+        else if (n >= 0 && n < a.order)
             /* call _SumDim function */
             _SumDim(&a, &b, &a, n, beta);
-        }
-        else {
+        else
             ShowNTErrors("Something is wrong!");
-        }
     }
 }
 
@@ -247,7 +244,7 @@ make a new tensor c to keep the result and return it
 >> beta - the scaling factor
 << return - the result of tensor summation
 */
-XTensor Sum(const XTensor &a, const XTensor &b, DTYPE beta)
+XTensor Sum(const XTensor & a, const XTensor & b, DTYPE beta)
 {
     XTensor c(&a);
     c.SetTMPFlag();
@@ -294,7 +291,7 @@ tensor summation c = a + b * \beta
 >> b - another tensor
 >> beta - the scaling factor
 */
-void Sum(const XTensor &a, const XTensor &b, XTensor &c, DTYPE beta)
+void Sum(const XTensor & a, const XTensor & b, XTensor & c, DTYPE beta)
 {
     if (!c.isInit || !IsSameShaped(a, c)) {
         InitTensorV2(&c, &a);