| 135 |  |  | 
| 136 |  | return tmp; | 
| 137 |  | } | 
| 138 | – |  | 
| 139 | – | /** | 
| 140 | – | * Returns the tensor contraction (double dot product) of two rank 2 | 
| 141 | – | * tensors (or Matrices) | 
| 142 | – | * @param t1 first tensor | 
| 143 | – | * @param t2 second tensor | 
| 144 | – | * @return the tensor contraction (double dot product) of t1 and t2 | 
| 145 | – | */ | 
| 146 | – | Real doubleDot( const SquareMatrix<Real, Dim>& t1, const SquareMatrix<Real, Dim>& t2 ) { | 
| 147 | – | Real tmp; | 
| 148 | – | tmp = 0; | 
| 149 | – |  | 
| 150 | – | for (unsigned int i = 0; i < Dim; i++) | 
| 151 | – | for (unsigned int j =0; j < Dim; j++) | 
| 152 | – | tmp += t1[i][j] * t2[i][j]; | 
| 153 | – |  | 
| 154 | – | return tmp; | 
| 155 | – | } | 
| 138 |  |  | 
| 157 | – |  | 
| 139 |  | /** Tests if this matrix is symmetrix. */ | 
| 140 |  | bool isSymmetric() const { | 
| 141 |  | for (unsigned int i = 0; i < Dim - 1; i++) |