This script is designed to generate pre-main sequence models for a given range of stellar masses and chemical composition. It uses the Python libraries numpy for numeric operations, such as generating a range of masses, and argparse for parsing command line arguments. The user provides a path to a chemical composition file, a range of masses (low, high, and step), and optionally, an output directory and a composition name to use in the models. The script integrates functionalities from the 'pysep' library to open, parse the chemical composition file, and generate the pre-main sequence models accordingly.

from pysep.opac.tops import open_and_parse
from pysep.newpoly.popFileToPolyModel import generate_prems_models
 
from numpy import arange
import argparse
 
if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Generate pre mainsequence models given a chemical composition file for a range of masses")
    parser.add_argument("path", help="path to chemical composition file", type=str)
    parser.add_argument("mlow", help="low mass range of pre main sequence models to generate", type=float)
    parser.add_argument("mhigh", help="high mass range of pre main sequence models to generate", type=float)
    parser.add_argument("mstep", help="step size betweem pre main sequence masse", type=float)
    parser.add_argument("-o", "--output", help="directory to output pre main sequence models too", type=str, default=".")
    parser.add_argument("-c", "--compName", help="Composition name to use in the premain sequence model", type=str, default="comp")
 
    args = parser.parse_args()
    masses = arange(args.mlow, args.mhigh, args.mstep)
 
    parsed = open_and_parse(args.path)
 
    generate_prems_models(parsed, masses, args.output, compName=args.compName, DDAGE=1000)