delay_to_dm.py

#!/usr/bin/env python

import sys
import argparse

def delayToDM(delay, nu1, nu2):
    return abs(delay / (4.15*((nu1**-2) - (nu2**-2))))
    
def DMToDelay(DM, nu1, nu2):
    return 1.e-3*abs(4.15 * DM * ((nu1**-2) - (nu2**-2)))

if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument('--delay', dest='delay', default=0.0, type=float,
                        help="Delay in seconds (set to convert delay to DM)")
    parser.add_argument('--DM', dest='DM', default=0.0, type=float,
                        help="DM in pc cm^-3 (set to convert DM to delay)")
    parser.add_argument('--nu1', dest='nu1', default=185, type=float,
                        help="lowest frequency in MHz")
    parser.add_argument('--nu2', dest='nu2', default=215, type=float,
                        help="highest frequency in MHz")
    args = parser.parse_args()

    if args.delay != 0.0:
        print(delayToDM(1.e3*args.delay, args.nu1/1.e3, args.nu2/1.e3))
    elif args.DM != 0.0:
        print(DMToDelay(args.DM, args.nu1/1.e3, args.nu2/1.e3))
    else:
        print("Must set either delay or DM.")