def load_param_names(fname):
    """
    Load parameter names from Fisher matrix with a given filename.
    (Names are stored as a header comment.)
    """
    f = open(fname, 'r')
    hdr = f.readline()
    if hdr[0] == '#':
        names = hdr.split()[1:] # (trim leading #)
    else:
        raise ValueError("Unable to process line 0 of %s as a header." % fname)
    f.close()
    return names