Add gaussian psf to AtmosphericPSF #197
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The latter seems to be more robust than the former.
... instead of the FWHM at 500nm.
This is to represent unmodeled additional contributions to the PSF. The default value of 0.3 arcsec FWHM comes from the 0.4 arcsec represented in LTS-124, minus (in quadrature) the modeled contributions of 0.26 arcsec for diffusion, 0.1 arcsec for the optics design, and 0.09 arcsec for for residual misalignments, and then rounded up from 0.27 to 0.3.
| @@ -200,4 +228,9 @@ def _getPSF(self, xPupil=None, yPupil=None, gsparams=None): | |||
| t0=self.t0, | |||
| exptime=self.exptime, | |||
| gsparams=gsparams) | |||
| if self.gaussianFWHM > 0.0: | |||
| psf = galsim.Convolve( | |||
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@jmeyers314 @rmjarvis Unfortunately, doing this convolution breaks this code: https://github.com/lsst/sims_GalSimInterface/blob/master/python/lsst/sims/GalSimInterface/galSimInterpreter.py#L1006
Could you guys have a look please?
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Sorry. That section was rather hacky, depending on some implementation details that I guess are now being changed. Probably a sign of bad design...
But in the interest of just getting this working, rather than refactoring that part of the code, I think you just need to swap the order of the items in this Convolve. Put the Gaussian first, and the current psf second.
If that doesn't work, please post (here if you want, or on Slack if that's easier) the exact error message that you are getting from the fft section.
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But in the interest of just getting this working, rather than refactoring that part of the code, I think you just need to swap the order of the items in this Convolve. Put the Gaussian first, and the current psf second.
That's the first thing I tried, but the last item in obj.original.obj_list is still a Convolution object...obj.original.obj_list[-1].obj_list[-1] would be the PhaseScreenPSF that we'd want to replace, but that's only if gaussianFWHM > 0. I can see increasingly hacky ways of getting this to work, but I thought you guys might want to consider some design changes.
In any case, here's the error I see:
Traceback (most recent call last):
File "/global/cscratch1/sd/jchiang8/desc/dev/imSim/bin/imsim.py", line 91, in <module>
image_simulator.run(processes=args.processes)
File "/global/cscratch1/sd/jchiang8/desc/dev/imSim/python/desc/imsim/ImageSimulator.py", line 253, in run
results.append(simulate_sensor(self.gs_obj_dict[det_name]))
File "/global/cscratch1/sd/jchiang8/desc/dev/imSim/python/desc/imsim/ImageSimulator.py", line 392, in __call__
fft_sb_thresh=fft_sb_thresh)
File "/global/cscratch1/sd/jchiang8/desc/dev/sims_GalSimInterface/python/lsst/sims/GalSimInterface/galSimInterpreter.py", line 940, in drawObject
gain=detector.photParams.gain)
File "/global/cscratch1/sd/jchiang8/desc/dev/galsim_local/lib/python3.6/site-packages/galsim/gsobject.py", line 1585, in drawImage
self._prepareDraw()
File "/global/cscratch1/sd/jchiang8/desc/dev/galsim_local/lib/python3.6/site-packages/galsim/transform.py", line 274, in _prepareDraw
self._original._prepareDraw()
File "/global/cscratch1/sd/jchiang8/desc/dev/galsim_local/lib/python3.6/site-packages/galsim/convolve.py", line 285, in _prepareDraw
obj._prepareDraw()
File "/global/cscratch1/sd/jchiang8/desc/dev/galsim_local/lib/python3.6/site-packages/galsim/convolve.py", line 285, in _prepareDraw
obj._prepareDraw()
File "/global/cscratch1/sd/jchiang8/desc/dev/galsim_local/lib/python3.6/site-packages/galsim/phase_psf.py", line 1397, in _prepareDraw
self._screen_list._prepareDraw()
File "/global/cscratch1/sd/jchiang8/desc/dev/galsim_local/lib/python3.6/site-packages/galsim/phase_psf.py", line 868, in _prepareDraw
psf._step()
File "/global/cscratch1/sd/jchiang8/desc/dev/galsim_local/lib/python3.6/site-packages/galsim/phase_psf.py", line 1406, in _step
wf = self._screen_list._wavefront(u, v, None, self.theta)
File "/global/cscratch1/sd/jchiang8/desc/dev/galsim_local/lib/python3.6/site-packages/galsim/phase_psf.py", line 927, in _wavefront
return np.sum([layer._wavefront(u, v, t, theta) for layer in self], axis=0)
File "/global/cscratch1/sd/jchiang8/desc/dev/galsim_local/lib/python3.6/site-packages/galsim/phase_psf.py", line 927, in <listcomp>
return np.sum([layer._wavefront(u, v, t, theta) for layer in self], axis=0)
AttributeError: 'OptWF' object has no attribute '_wavefront'
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Ah, right. I forgot we got rid of a feature we used to have where if any argument to a Convolve was itself a Convolution, it would combine the lists. I guess we could do that manually in PSFbase.applyPSF:
if isinstance(psf, galsim.Convolution):
return galsim.Convolution([obj] + psf.obj_list)
else:
return galsim.Convolution(obj, psf)
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Thanks, making that change and swapping the order of the items in the Convolve in atmPSF._getPSF addresses the issue. I'll go ahead and make the PR in sims_GalSimInterface.
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@jmeyers314 @cwwalter I think this is ready to merge. I added some code to read the |
This PR follows from the discussion on slack channel #desc-dm-dc2 around Jan 9-11, 2019. It adds an option to convolve in an additional Gaussian PSF to the AtmosphericPSF model to account for otherwise unmodeled effects, such as dome seeing, polishing errors, vibration, and other errors listed in document LTS-124.
I also took the opportunity to switch from using
fsolveto invert the Tokovinin fitting formula for r0_500 tobisect, which I've found to be more robust. I also changed the code to target the seeing at the specific filter effective wavelength being drawn instead of the seeing at 500 nm. These two changes are mostly aesthetic, yielding delivered FWHM differences around ~0.01 arcseconds.