Atmosphere vs. AtmosphericScreen then PhaseScreenList

Question

I'm trying to use the code provided in phase_screens.py that can reproduce the plot by Jee & Tyson (2011). When I try to run the line

    psf = atm.makePSF(lam = 700., exptime = 15., diam = 8.4, obscuration = .6)

I get an AttributeError that says, 'generator' object has no attribute 'stepK.'

But atm has the type PhaseScreenList. Why can I not call atm.makePSF or atm.wavefront? In making a multi-screen atmosphere, there subtle differences between (1) passing lists as parameters inside the Atmosphere constructor and (2) defining AtmosphericScreen objects then passing a list of the objects inside the PhaseScreenList constructor? Thank you in advance!

Answer 1

I think this is a bug in the Atmosphere() function that will be fixed when branch #824 is merged to master. If you can work from that branch now, then you'll probably be okay. If you want to just patch master, then I think replacing the last line of Atmosphere() with the following should work:

    return galsim.PhaseScreenList(
        [AtmosphericScreen(**kw) 
         for kw in galsim.utilities.lod_to_dol(kwargs, nmax)])