New python version of Keeton's gravlens software.
Dependences:
- numpy
- scipy
- matplotlib
- shapely (https://pypi.org/project/Shapely/)
Current mass models:
- point mass ('ptmass')
- Singular Isothermal Sphere ('SIS')
A fundamental unit is a lens plane:
class lensplane(ID,parr=[],kappa=0,gammac=0,gammas=0,Dl_Ds=0.5):
# - ID = string identifying mass model
# - parr = [[x0,y0,...], [x1,y1,...], ...]
# - kappa,gamma_c,gamma_s = convergence and shear
# - Dl_Ds is the ratio (lens distance)/(source distance);
# used only in multiplane lensing
One or more lens planes can be combined into a lens model:
class lensmodel(plane_list,xtol=1.0e-5,position_mode='obs'):
# - plane_list is a list of lensplane structures
# - xtol is the tolerance used for finding images
# - position_mode is important for multiplane lensing;
# + 'obs' indicates that the specified positions are observed,
# so the intrinsic positions must account for foreground bending
# + 'fix' indicates that the specified positions are fixed in space
Here are some key routines:
##################################################################
# report some key information about the model
##################################################################
lensmodel.info()
##################################################################
# commands to specify the grid:
# - maingrid is Cartesian
# - galgrid is polar grid(s) centered on the mass component(s)
##################################################################
lensmodel.maingrid(xlo,xhi,nx,ylo,yhi,ny)
lensmodel.galgrid(rlo,rhi,nr,ntheta)
##################################################################
# compute the tiling
##################################################################
lensmodel.tile()
##################################################################
# solve the lens equation and report the image(s) for a given
# source position or set of source positions
##################################################################f
lensmodel.findimg(u)
##################################################################
# general purpose plotter, with options to plot the grid,
# critical curve(s) and caustic(s), and source/image combinations
##################################################################
lensmodel.plot(imgrange=[],srcrange=[],plotgrid=False,plotcrit='black',src=[],file=''):