public static Basic2DMatrix diagonal(int size, double diagonal) {
        double[][] array = new double[size][size];

        for (int i = 0; i < size; i++) {
            array[i][i] = diagonal;
        }

        return new Basic2DMatrix(array);
    }
public static Basic2DMatrix diagonal ( int size , double diagonal ) { double [ ] [ ] array = new double [ size ] [ size ] ; for ( int i = 0 ; i < size ; i ++ ) { array [ i ] [ i ] = diagonal ; } return new Basic2DMatrix ( array ) ; }
Creates a diagonal {@link Basic2DMatrix} of the given {@code size} whose
diagonal elements are equal to {@code diagonal}.