def heatmap_options():
    """
    Options for generating the correlation heatmap
    """
    parser = argparse.ArgumentParser(add_help=False)
    heatmap = parser.add_argument_group('Heatmap options')

    heatmap.add_argument('--plotHeight',
                         help='Plot height in cm. (Default: %(default)s)',
                         type=float,
                         default=9.5)

    heatmap.add_argument('--plotWidth',
                         help='Plot width in cm. The minimum value is 1 cm. (Default: %(default)s)',
                         type=float,
                         default=11)

    heatmap.add_argument('--zMin', '-min',
                         default=None,
                         help='Minimum value for the heatmap intensities. '
                              'If not specified, the value is set automatically',
                         type=float)

    heatmap.add_argument('--zMax', '-max',
                         default=None,
                         help='Maximum value for the heatmap intensities.'
                              'If not specified, the value is set automatically',
                         type=float)

    heatmap.add_argument(
        '--colorMap', default='jet',
        metavar='',
        help='Color map to use for the heatmap. Available values can be '
             'seen here: '
             'http://matplotlib.org/examples/color/colormaps_reference.html')

    heatmap.add_argument('--plotNumbers',
                         help='If set, then the correlation number is plotted '
                         'on top of the heatmap. This option is only valid when plotting a heatmap.',
                         action='store_true',
                         required=False)

    return parser