This directory contains a number of scripts useful for testing GalSim functionality, but not
necessary and/or feasible to run as unit tests; it also contains documentation on some of the GalSim
developers' scientific choices.

---Interpolation---

test_interpolants.py: a script to test the deviations from expected behavior of the x- and k-space
interpolants for the RealGalaxy class.

test_interpolants_parametric.py: a script to perform the same tests as test_interpolants.py, but
using as images InterpolatedImages constructed from parametric Sersics instead.

plot_test_interpolants.py: makes readable graphs from the output of the previous two scripts.

lensing_engine_interpolants.py: a script to check the effect of using interpolants for gridded
shears.

---Correlation functions---

corrfuncs/test_cf_interpolant.py: makes upsampled plots of correlation functions to see how their
interpolants behaves and check whether this corresponds to what is physically required.  See the
full discussion at https://github.com/GalSim-developers/GalSim/pull/452#discussion-diff-5701561

corrfuncs/test_cf_periodicity.py: tests to see how the assumption of purely positive power spectra
holds up under the periodicity correction, and other effects.  See the full discussion at
https://github.com/GalSim-developers/GalSim/issues/430.

---Other GalSim functionality---

lensing_engine.pdf: a document describing the mathematics behind the GalSim "lensing engine"
(galsim/lensing_ps.py) that takes a shear power spectrum and generates a random realization of a
shear field, and showing some tests of its functionality.

cf.eps, cf10.eps: figures that are included in lensing_engine.pdf.

shera_vs_sbprofile.tex: a document from early in the GalSim development comparing its results with
realistic galaxies against those from the SHERA pipeline.  (Somewhat outdated, mainly left for
historical purposes.)

test_mom_timing.py: a script that can be used to test the speed of the adaptive moments and PSF
correction code that is included with GalSim, for a variety of different types of profiles.  Can be
useful for tests of updates to that module, to see how the changes affect the speed of calculations.

---Possible code modules for the future---

atmos_factfinding.pdf: a document by Barney Rowe and Joerg Dietrich outlining an early exploration
of possibilities for writing our own atmospheric PSF model based on Gaussian random field
realizations of phase screens, see https://github.com/GalSim-developers/GalSim/issues/169.
