This module is very similar to MakeGalSet, only output images are the product of drizzling several lower-resolution images together.

Creates a set of galaxy images. That is, and array of images each of which has a particular realization of a galaxy model. This module creates two separate arrays: one in which the galaxies have been biased by some constant amount ("Biased"), and a second in which the galaxies have no such distortion bias (gamma1=gamma2=0, "Unbiased").

The output of this module is as a base for many simulation chains, and as an intermediate step in several others.

There are many different options to this module. The module can optionally increase the galaxy counts each time its process() stage is called. This module can optionally create "Big" galaxies, which are placed in a special spot in memory and often serve as a base to create derivative galaxy sets (with ReduceGalSet for instance).

The user must specify the number of images to drizzle together as well as the drizzle parameters. The input images to the drizzle algorithm will be randomly offset from each other (though they will have the same rotations and scales). If the FixedStep keyword is set, exactly four drizzles will be used, and each will be offset by half a pixel in each direction.

Parameters ,

Name	Type	Description
BiasedCount	int	Number of biased galaxies to create.
UnbiasedCount	int	Number of unbiased galaxies to create.
BiasedStep	int	Amount to increase BiasedCount during each process(). Default is 0.
UnbiasedStep	int	Amount to increase UnbiasedCount during each process(). Default is 0.
BiasedMax	int	Maximum number of biased galaxies (useful only with BiasedStep).
UnbiasedMax	int	Maximum number of unbiased galaxies (useful only with UnbiasedStep).
Gamma1	double	Amount of constant x-y shear bias to put in biased galaxies.
Gamma2	double	Amount of constant 45deg to x-y shear bias to put in biased galaxies.
GalTag	string	Tag name of galaxy model to use when drawing the galaxies.
Width	int	Pixel width of each final image.
Height	int	Pixel height of each final image.
Seed	int	Value to seed random number generator with. If not specified, a random seed is used.
NumDithers	int	Number of low-resolution images to create and input to the drizzle algorithm.
DrizzleScale	double	Ratio of the lower resolution images to the final images resolution. That is, if this parameter is 0.5, the final image will be created from images with half the resolution (1/4 of the pixels).
DropFrac	double	An input to the drizzle algorithm: amount to scale down the pixels as they are dropped on to the final grid.
FixedStep	keyword	If set, ignore the NumDithers parameters, and drizzle together four images that are offset by a half pixel in each direction.
Big	keyword	If specified, place galaxy images into variables labeled "Big" as specified below.
Verbose	keyword	If set, print debugging information to cout.

Inputs

Name	Type	Description

Outputs

Name	Type	Description
GalSet/Gamma1	double	The amount of shear in x-y direction with which the biased galaxies were biased.
GalSet/Gamma2	double	The amount of shear 45deg to x-y direction with which the biased galaxies were biased.
GalSet/BiasedImages	double*	Array of pixel values for the biased galaxy images.
GalSet/BiasedCount	int	Number of biased images creates.
GalSet/UnbiasedImages	double*	Array of pixel values for the unbiased galaxy images.
GalSet/UnbiasedCount	int	Number of unbiased images creates.
GalSet/Seed	int	Seed used to generate these images.

Note: If the "Big" keyword is set, all of the above variable names except for Gamma1, Gamma2, Seed, BiasedCount and UnbiasedCount will be prepended by the string "Big". So BigWidth, BigUnbiasedImages etc.