def parse_entry(entry):
    """ Separates an entry into a numeric value and a tied/fixed
    parameter, if present.
    """
    if entry.startswith('nan'):
        val = float(entry[:3])
        par = entry[3:]
    else:
        i = -1
        while not entry[i].isdigit():  i -= 1
        if i != -1:
            val = float(entry[:i+1])
            par = entry[i+1:]
        else:
            val = float(entry)
            par = ''

    return val,par