code: private Matrix calculateT(IBasis basis) {
          int size = basis.getSize();
          Matrix J = new Matrix(size, size);
          int i, j;
          for (i = 0; i < size; i++)
              for (j = 0; j < size; j++)
                  // (1/2) * -<d^2/dx^2 chi_i | chi_j>
                  J.matrix[i][j] = basis.calcJ(j, i) / 2; // Attention indicies are exchanged
  
          return J;
      }
docs: Calculates the matrix for the kinetic energy
  
  T_i,j = (1/2) * -<d^2/dx^2 chi_i | chi_j>