add for adding equal tensor operations

Geo/STensor3.h

@@ -281,8 +281,9 @@ class STensor3 {
     return ithis;
   }
 
-  void operator = (const STensor3 &other){
+  STensor3& operator = (const STensor3 &other){
     for (int i = 0; i < 9; i++) _val[i] = other._val[i];
+    return *this;
   }
 
   STensor3 operator + (const STensor3 &other) const

Geo/SVector3.h

@@ -70,6 +70,12 @@ class SVector3 {
     P[0] = v; P[1] = v; P[2] = v;
     return *this;
   }
+  SVector3 & operator = (const SVector3& a)
+  {
+    P[0] = a[0]; P[1] = a[1]; P[2] = a[2];
+    return *this;
+  }
+  
   operator double *() { return P; }
   void print(std::string name="") const
   {

Solver/STensor43.h

@@ -83,11 +83,17 @@ class STensor43 {
     for (int i = 0; i < 81; i++) _val[i] -= other._val[i];
     return *this;
   }
+  STensor43& operator = (const STensor43 &other)
+  {
+    for (int i = 0; i < 81; i++) _val[i] = other._val[i];
+    return *this;
+  }
   STensor43& operator *= (const double &other)
   {
     for (int i = 0; i < 81; i++) _val[i] *= other;
     return *this;
   }
+  
   STensor43 transpose (int n, int m) const
   {
     STensor43 ithis;

Solver/STensor53.h

@@ -18,6 +18,15 @@ class STensor53 {
     inline double operator()(int i, int j, int k, int l, int m) const{
       return _val[i][j][k][l][m];
     };
+    STensor53& operator = (const STensor53 &other){
+      for (int i=0; i<3; i++)
+        for (int j=0; j<3; j++)
+          for (int k=0; k<3; k++)
+            for (int l=0; l<3; l++)
+              for (int m=0; m<3; m++)
+                _val[i][j][k][l][m] = other._val[i][j][k][l][m];
+      return *this;
+    };
     STensor53& operator += (const STensor53 &other){
       for (int i=0; i<3; i++)
         for (int j=0; j<3; j++)

Solver/STensor63.h

@@ -18,6 +18,16 @@ class STensor63{
     inline double operator()(int i, int j, int k, int l, int m, int n) const{
       return _val[i][j][k][l][m][n];
     };
+    STensor63& operator = (const STensor63 &other){
+      for (int i=0; i<3; i++)
+        for (int j=0; j<3; j++)
+          for (int k=0; k<3; k++)
+            for (int l=0; l<3; l++)
+              for (int m=0; m<3; m++)
+                for (int n=0; n<3; n++)
+                  _val[i][j][k][l][m][n] = other._val[i][j][k][l][m][n];
+      return *this;
+    };
     STensor63& operator += (const STensor63 &other){
       for (int i=0; i<3; i++)
         for (int j=0; j<3; j++)