run_imsim.py

#!/usr/bin/env python
"""
This is the imSim program, used to drive GalSim to simulate the LSST.  Written
for the DESC collaboration and LSST project.  This version of the program can
read phoSim instance files as is.  It leverages the LSST Sims GalSim interface
code found in sims_GalSimInterface.

Modified by James Perry for UK DC2 runs to fetch random seed from input file
and create Atmospheric PSF rather than default Kolmogorov.
"""
import os
import argparse
import warnings
from astropy._erfa import ErfaWarning

import galsim
import desc.imsim

parser = argparse.ArgumentParser()
parser.add_argument('instcat', help="The instance catalog")
parser.add_argument('-n', '--numrows', default=None, type=int,
                    help="Read the first numrows of the file.")
parser.add_argument('--outdir', type=str, default='fits',
                    help='Output directory for eimage file')
parser.add_argument('--sensors', type=str, default=None,
                    help='Sensors to simulate, e.g., '
                    '"R:2,2 S:1,1^R:2,2 S:1,0". '
                    'If None, then simulate all sensors with sources on them')
parser.add_argument('--config_file', type=str, default=None,
                    help="Config file. If None, the default config will be used.")
parser.add_argument('--log_level', type=str,
                    choices=['DEBUG', 'INFO', 'WARN', 'ERROR', 'CRITICAL'],
                    default='INFO', help='Logging level. Default: INFO')
parser.add_argument('--disable_sensor_model', default=False,
                    action='store_true',
                    help='disable sensor effects')
parser.add_argument('--file_id', type=str, default=None,
                    help='ID string to use for checkpoint filenames.')
parser.add_argument('--create_centroid_file', default=False, action="store_true",
                    help='Write centroid file(s).')
parser.add_argument('--processes', type=int, default=1,
                    help='number of processes to use in multiprocessing mode')
parser.add_argument('--psf_file', type=str, default=None,
                    help="Pickle file containing for the persisted PSF. "
                    "If the file exists, the psf will be loaded from that "
                    "file, ignoring the --psf option; "
                    "if not, a PSF will be created and saved to that filename.")
parser.add_argument('--image_path', type=str, default=None,
                    help="search path for FITS postage stamp images."
                    "This will be prepended to any existing IMSIM_IMAGE_PATH "
                    "environment variable, for which $CWD is included by "
                    "default.")

args = parser.parse_args()

# Read in the config
desc.imsim.read_config(args.config_file)

# Prepend any additional paths to IMSIM_IMAGE_PATH.
if args.image_path is not None:
    os.environ['IMSIM_IMAGE_PATH']\
        = ':'.join([args.image_path] + desc.imsim.get_image_dirs())

commands = desc.imsim.metadata_from_file(args.instcat)
obs_md = desc.imsim.phosim_obs_metadata(commands)
seed = commands['seed']

rng = galsim.UniformDeviate(seed)
psf = desc.imsim.make_psf('Atmospheric', obs_md, rng=rng)
apply_sensor_model = True

sensor_list = args.sensors.split('^') if args.sensors is not None \
    else args.sensors

with warnings.catch_warnings():
    warnings.filterwarnings('ignore', 'ERFA', ErfaWarning)
    image_simulator \
        = desc.imsim.ImageSimulator(args.instcat, psf,
                                    numRows=args.numrows,
                                    config=args.config_file,
                                    seed=seed,
                                    outdir=args.outdir,
                                    sensor_list=sensor_list,
                                    apply_sensor_model=apply_sensor_model,
                                    create_centroid_file=args.create_centroid_file,
                                    file_id=args.file_id,
                                    log_level=args.log_level)

    image_simulator.run(processes=args.processes)