Mass models

setlens Ngal Nmod
  ID p[1] x y e te g tg p[8] p[9] p[10]     # galaxy #1
  ID p[1] x y e te g tg p[8] p[9] p[10]     # galaxy #2
  ...
  0 0 0 0 0 0 0 0 0 0
  0 0 0 0 0 0 0 0 0 0
  ...

Here Ngal is the number of galaxies per model, while Nmod is the number of different models you are giving.

Each galaxy is specified by a text label and 10 parameters. The parameters are as follows:

• p[1] : some lensing strength
• (x,y) : position
• (e,te) : ellipticity and its position angle
• (g,tg) : shear and its position angle
• p[8], p[9], p[10] : utility parameters

After giving the model parameters, you give a set of flags (the rows of 0's above). These indicate which parameters are allowed to vary in modeling.

Here is a table of the mass models available in gravlens/lensmodel.