datagen script

The main simulator application is the datagen.py script.

Simple batch mode

The simples run of the simulator specifies a CSV file with parameters, and generates the distorted image for each row.

python3 CosmoSimPy/datagen.py  --csvfile Dataset/debug.csv

Some useful options

• --directory dir : directory path for output files
• --maxcount n: Maximum number of images to generate
• --reflines : Add reference (axes) lines to the image
• --criticalcurves : Add critical curves to the distorted image
• --centred : centre image on the centre of light
• --nterms : Number of Roulettes terms
• --imagesize : image size for calculations
• --cropsize : Final image size
• Masking (see Roulette Masking
  • --maskradius : Set explicit masking radius
  • --mask : Mask out the convergence circle
  • --showmask : Mark the convergence circle
  • --maskscale : Scaling factor for the mask radius

Extra output images

These options create additional image files at different stages of the simulation

• --original : Also write original image before centring
• --apparent : write apparent image
• --actual : write actual image

Setting parameters on the command line

Parameters which are not set in the CSV file, can be set on the command line. The CSV file takes precedence though.

• --lensmode m : lens model
• --modelmode m : simulation model
• --sourcemode m : source model
• --sampled : Use sample lens model
• --config : Configuration. Specifying Simulation and Lens Model together.
• --x x --y y : Set the source position in Cartesian co-ordinates.
• --x x --phi phi : Set the source position in Polar co-ordinates. If both --y and --phi are specified, --y takes precedence.
• --sigma : source size (sigma)
• --sigma2 : secondary source size (sigma2) for elliptical sources
• --theta : source rotation angle (theta)
• --chi : lens distance ratio ($\chi$)
• --einsteinradius : Einstein radius
• --ratio : Ratio (usually Elliptic eccentricity) for the lens
• --orientation : Orientation of the lens
• --outfile : Output file for roulette amplitudes, see Roulette Resimulation

Undocumented options

These options are not used in current research and have not been tested in recent versions, if they have been implemented at all.

• --name : simulation name
• Joining images
  • --components n : Number of components for joined image
  • --join : Join several images from different viewpoints
• --amplitudes : Amplitudes input file
• --psiplot' : Plot lens potential as 3D surface
• --kappaplot : Plot mass distribution as 3D surface
• --family : Several images moving the viewpoint
• --no-xireference calculate roulette amplitudes in the centre of light, instead of the source centre
  • this does not change the expansion point used for simulation in datagen.py.
  • requires --centred, lest the origin be the origin and the model collapse
  • --xireference is the default, using the same expansion point as the original simulation.

It is also possible to generate a single image by ommitting the CSV file and giving all parameters on the command line.