How would one go about setting the random seed for functions like the following:
image = galsim.imageD(x_lim,y_lim,scale)
image_gal = gal_obj.drawShoot(image=image)
I need a deterministic seed but am not sure how to set it.
Use the "rng" keyword argument when drawing. So for example, you could do
image = galsim.ImageD(x_lim, y_lim, scale=scale)
image_gal = gal_obj.drawShoot(image=image, rng=galsim.BaseDeviate(1234567))
if you want deterministic photon-shooting using the seed 1234567.
On a more minor note, use of drawShoot is still supported but is discouraged as of GalSim v1.1. Instead, we are encouraging use of a unified drawing method that allows both photon-shooting and DFT rendering. In that case, the last line of the code snippet would become
image_gal = gal_obj.drawImage(image=image, rng=galsim.BaseDeviate(1234567), method='phot')
(That is, assuming you have GalSim v1.1 installed.)