ValueError: Got unlikely transparency value

[apcooper]

I'm trying to run surveysim as in https://github.com/desihub/quicksurvey_example/blob/master/survey/surveysim_HA.sh

The first call to surveysim after making the initial surveyplan fails with the following:

Traceback (most recent call last):
  File "/gpfs/data/DESI/software/modules/surveysim/0.7.1/bin/surveysim", line 4, in <module>
    __import__('pkg_resources').run_script('surveysim==0.6.0.dev1', 'surveysim')
  File "/gpfs/data/dph3apc/anaconda/3/lib/python3.5/site-packages/setuptools-23.0.0-py3.5.egg/pkg_resources/__init__.py", line 719, in run_script
  File "/gpfs/data/dph3apc/anaconda/3/lib/python3.5/site-packages/setuptools-23.0.0-py3.5.egg/pkg_resources/__init__.py", line 1504, in run_script
  File "/gpfs/data/DESI/software/modules/surveysim/0.7.1/lib/python3.5/site-packages/surveysim-0.6.0.dev1-py3.5.egg/EGG-INFO/scripts/surveysim", line 15, in <module>
    surveysim.scripts.surveysim.main(args)
  File "/gpfs/data/DESI/software/modules/surveysim/0.7.1/lib/python3.5/site-packages/surveysim-0.6.0.dev1-py3.5.egg/surveysim/scripts/surveysim.py", line 162, in main
    while simulator.next_day():
  File "/gpfs/data/DESI/software/modules/surveysim/0.7.1/lib/python3.5/site-packages/surveysim-0.6.0.dev1-py3.5.egg/surveysim/simulator.py", line 148, in next_day
    self.plan, self.gen)
  File "/gpfs/data/DESI/software/modules/surveysim/0.7.1/lib/python3.5/site-packages/surveysim-0.6.0.dev1-py3.5.egg/surveysim/nightops.py", line 97, in nightOps
    strategy, plan)
  File "/gpfs/data/DESI/software/modules/desisurvey/penalty_value/lib/python3.5/site-packages/desisurvey-0.8.2.dev415-py3.5.egg/desisurvey/schedule.py", line 449, in next_tile
    when, cutoff, seeing, transparency, progress, snr2frac, mask)
  File "/gpfs/data/DESI/software/modules/desisurvey/penalty_value/lib/python3.5/site-packages/desisurvey-0.8.2.dev415-py3.5.egg/desisurvey/schedule.py", line 223, in instantaneous_efficiency
    eff /= desisurvey.etc.transparency_exposure_factor(transparency)
  File "/gpfs/data/DESI/software/modules/desisurvey/penalty_value/lib/python3.5/site-packages/desisurvey-0.8.2.dev415-py3.5.egg/desisurvey/etc.py", line 69, in transparency_exposure_factor
    raise ValueError('Got unlikely transparency value < 1e-9.')
ValueError: Got unlikely transparency value < 1e-9.

Not sure if this is a bug -- if not, suggestions for how to proceed would be appreciated.

[dkirkby]

I already fixed this on my development branch, but that's probably ~1 week away from merging back into master. If this is blocking you, you could either:

• make a one-line fix in surveysim.weather in your local checkout.
• update to my dev branch, which will schedule more sensible exposures but require more extensive changes.

The best choice depends on what you are using the surveysim for: do you just want to exercise the machinery and produce outputs with the correct structure, etc, or are you using the simulated exposures for some study where realism is important?

[apcooper]

I just want a reasonable set of outputs to exercise the latest quicksurvey, so for now I'm happy to hack surveysim.weather if you can let me know what the change is.

[dkirkby]

The change I made is here. You should be able to apply this change using:

git fetch
git cherry-pick b0b5e58

but I haven't actually tested this. In any case, please don't push this change back to github.

[dkirkby]

Closing since this issue is fixed on the master branch now after recent PRs.