descwl-shear-sims

simple simulations for testing weak lensing shear measurement

Installation

It is best to use pip to install

pip install .

If you are installing into a conda environment, you should add --no-deps to the command above and make sure to install the dependencies with conda.

Installing with all the dependencies

Matt Becker has put up examples to install the full dependencies, including the DM STack:

Full Installation with Dependencies

Getting the Simulation Input Data

To use galaxy models from WeakLensingDeblending, and to use realistic star masks, get this tar ball, untar it and set the $CATSIM_DIR environment variable to that location

wget https://www.cosmo.bnl.gov/www/esheldon/data/catsim.tar.gz
tar xvfz catsim.tar.gz
export CATSIM_DIR=/path/to/catsim

Example Usage

A simple sim

import numpy as np
from descwl_shear_sims.galaxies import FixedGalaxyCatalog
from descwl_shear_sims.sim import make_sim
from descwl_shear_sims.psfs import make_fixed_psf
seed = 8312
rng = np.random.RandomState(seed)

ntrial = 2
coadd_dim = 351
buff = 50

for trial in range(ntrial):
    print('trial: %d/%d' % (trial+1, ntrial))

    # galaxy catalog; you can make your own
    galaxy_catalog = FixedGalaxyCatalog(
        rng=rng,
        coadd_dim=coadd_dim,
        buff=buff,
        layout='random',
        mag=25,
        hlr=1.0,
    )

    # make a constant gaussian psf
    psf = make_fixed_psf(psf_type='gauss')

    # generate some simulation data, with a particular shear

    sim_data = make_sim(
        rng=rng,
        galaxy_catalog=galaxy_catalog,
        coadd_dim=coadd_dim,
        g1=0.02,
        g2=0.00,
        psf=psf,
    )

A sim with lots of features turned on

import numpy as np
from descwl_shear_sims.galaxies import WLDeblendGalaxyCatalog  # one of the galaxy catalog classes
from descwl_shear_sims.stars import StarCatalog  # star catalog class
from descwl_shear_sims.sim import make_sim
from descwl_shear_sims.psfs import make_ps_psf  # for making a power spectrum PSF
from descwl_shear_sims.sim import get_se_dim  # convert coadd dims to SE dims

seed = 8312
rng = np.random.RandomState(seed)

ntrial = 2
coadd_dim = 351
buff = 50
rotate = True
dither = True

# this is the single epoch image sized used by the sim, we need
# it for the power spectrum psf
se_dim = get_se_dim(coadd_dim=coadd_dim, rotate=rotate, dither=dither)

for trial in range(ntrial):
    print('trial: %d/%d' % (trial+1, ntrial))

    # galaxy catalog; you can make your own
    galaxy_catalog = WLDeblendGalaxyCatalog(
        rng=rng,
        coadd_dim=coadd_dim,
        buff=buff,
    )
    # star catalog; you can make one of these too
    star_catalog = StarCatalog(
        rng=rng,
        coadd_dim=coadd_dim,
        buff=buff,
    )
    # make a power-spectrum PSF, again you can make your own PSF
    psf = make_ps_psf(rng=rng, dim=se_dim)

    # generate some simulation data, with a particular shear,
    # and dithering, rotation, cosmic rays, bad columns, star bleeds
    # turned on.  By sending the star catalog we generate stars and
    # some can be saturated and bleed

    sim_data = make_sim(
        rng=rng,
        galaxy_catalog=galaxy_catalog,
        star_catalog=star_catalog,
        coadd_dim=coadd_dim,
        g1=0.02,
        g2=0.00,
        psf=psf,
        dither=dither,
        rotate=rotate,
        bands=['r', 'i', 'z'],
        noise_factor=0.58,
        cosmic_rays=True,
        bad_columns=True,
        star_bleeds=True,
    )

Documentation

The doc strings for the main public APIs are complete. See them for more details.

EiffL/descwl-shear-sims