docs: public Matrix getU () {
        Matrix X = MatrixFactory.createMatrix(n,n);
        for (int i = 0; i < n; i++) {
           for (int j = 0; j < n; j++) {
              if (i <= j) {
  					X.set(i, j, LU[i][j]);
              }
           }
        }
        return X;
     }