docs: public static void solveL( double L[] , double []b ,
                                 int m , int n ,
                                 int strideL , int offsetL , int offsetB )
      {
          for( int j = 0; j < n; j++ ) {
              for( int i = 0; i < m; i++ ) {
                  double sum = b[offsetB + i*n+j];
                  for( int k=0; k<i; k++ ) {
                      sum -= L[offsetL + i*strideL+k]* b[offsetB + k*n+j];
                  }
                  b[offsetB + i*n+j] = sum / L[offsetL + i*strideL+i];
              }
          }
      }