Getting started

This page will guide you through the first steps of working with GLAMER. It is assumed that you have a working library linked with your project. If necessary, review the pages on Installing GLAMER and Using GLAMER in your project for further information before getting started.

The full documentation of every class and function is at GLAMER++.

Read in Parameters

Within your main code the first thing to do is to read in the input parameter file. Your parameter file should contains all the parameters required to run the simulation. A sample parameter file is provided in the repository. A particular simulation will not require all the parameters to be specified. The parameter file should be read by constructing an InputParams object. See the InputParams class for options. If a parameter is required, but not present in the parameter file the program should throw an exception and notify you of which parameter needs to be included. If a parameters is in the parameters file that is not recognized a warning will be printed.

For a list of currently acceptable parameters with very short descriptions use InputParams::sample().

Example

In main() one needs to first read in the parameter file. This is done by constructing a InputParams object

InputParams params(paramfile);

where paramfile is a string containing the path and file name of your parameter file. A sample parameter file with all allowed parameters can be generated by InputParams::sample(). This can be printed to a usable parameters file with InputParams::PrintToFile().

#include "InputParams.h"

int main(int argc, const char* argv[])
{
    // create InputParams with sample values
    InputParams params(paramfile) = InputParams::sample();
    
    // print sample parameter file
    params.PrintToFile("sample_paramfile");
    
    // done
    return EXIT_SUCCESS;
}

Construct a Source

The source constructor takes the InputParams object and constructs one or many sources within a MixedVector member. See the class Source and all

• SourceUniform source(params) Makes the source a uniform surface brightness circle

• SourceMultiAnaGalaxy source(params) Makes many individual sources. Where they are read in is set in the parameter file.

Construct a Lens

A lens is constructed

Lens lens(params, &seed);

Multiple components to the lens are stored within the lens. See the Lens class documentationfor how to access them. These can be read in from a file which are generally called "field" lenses. The "main" lens(es) can be set by parameters in the parameter file or added by hand within main().

Construct the Grid

The Grid structure contains the image points and thier source points along with other information. Without further grid refinement the Grid can be used to make a map of deflection, convergence, shear or time-delay. Grid contains functions for outputing these. If no further grid refinement is desired for image or caustic finding, the GridMap structure can be used which requires signifcantly less memory overhead.

Image finding and Grid refinement

The mean functions used for image finding are

• find_images_kist(),
• find_images_microlens() and
• map_images(). And for finding critical curves / caustics
• find_crit()

These take a Grid and a Lens object. The found images are then stored in an array of ImageInfo structures.

Output

The Grid has some direct output functions for making maps that do not depend on sources (kappa, gamma, etc.). The ImageInfo structure has some information about the images found and contains a linked list of all the points within the image. Each point contains information about the kappa, gamma, source position, time-delay and in some cases the the surface brightness at that point.