public Matrix getIminus() {
        Matrix Iminus = new Matrix(size, size);
        int i, j;
        for (i = 0; i < size; i++)
            for (j = 0; j < size; j++)
                Iminus.matrix[i][j] = 0d;
        for (i = 1; i < size; i++)
            Iminus.matrix[i][i - 1] = Math.sqrt(J * J + J - (J - i) * (J - i) - (J - i));
        return Iminus;
    }
public Matrix getIminus ( ) { Matrix Iminus = new Matrix ( size , size ) ; int i , j ; for ( i = 0 ; i < size ; i ++ ) for ( j = 0 ; j < size ; j ++ ) Iminus . matrix [ i ] [ j ] = 0d ; for ( i = 1 ; i < size ; i ++ ) Iminus . matrix [ i ] [ i - 1 ] = Math . sqrt ( J * J + J - ( J - i ) * ( J - i ) - ( J - i ) ) ; return Iminus ; }
Calculates the I- operator