Noise sims in CAR and noise splits

[msyriac]

This is work in progress towards

1. noise sims in CAR, fixes https://github.com/simonsobs/map_based_simulations/issues/28
2. noise splits, fixes https://github.com/simonsobs/map_based_simulations/issues/30

Current changes include:

• API Change to SONoiseSimulator and restructuring so that only LAT is initialized by default
• Accepts shape,wcs pixell parameters for geometry
• Looks for saved noise template with nearest resolution and interpolates only if necessary
• Uses pixell.curvedsky.rand_map instead of synfast when not healpix
• Some docstring fixes
• Added nsplits option which just multiplies the noise power by nsplits and appends as many copies of simulated noise maps
• Added noise template generation script to repo
• Serve noise templates on http and download when installing
• Default mask value is nan for CAR; but allows mask value to be overridden for both healpix and CAR

To do:

• Standardize resolution/WCS choices with mapmaker/TOD codes

E.g. invocation:

bounds_deg = [-80.,40.]                                                                                                                                                                       
res_arcmin = 2.0                                                                                                                                                                              
shape,wcs = enmap.band_geometry(np.deg2rad(bounds_deg),res=np.deg2rad(res_arcmin/60.),proj='car')                                                                                             

nsim = mapsims.SONoiseSimulator(                                                                                                                                                              
        shape=shape,                                                                                                                                                                          
        wcs=wcs)                                                                                                                                                                              

ch = mapsims.SOChannel("LA", 145)                                                                                                                                                             
omap = nsim.simulate(ch, output_units="uK_CMB", seed=None)     

Output:

[msyriac]

@zonca This is ready to be merged once the requirements.txt issue #30 is solved. I will raise a separate issue for this to-do item: "Standardize resolution/WCS choices with mapmaker/TOD codes".

[zonca]

fixed in #32 and extra commits to master to fix readthedocs, can you rebase?

[msyriac]

Done.

[zonca]

@msyriac can you fix the errors on travis? consider also that NERSC /project is down until 1pm PST today, so that could cause some tests to fail.

[msyriac]

I can't even run the tests locally, since the test suite requires pytest-astropy which requires psutil which it doesn't seem can be compiled using Intel compilers. https://github.com/giampaolo/psutil/issues/1664

[zonca]

@msyriac can you just try to fix the variable undefined issue? I can then later pickup from there

[msyriac]

@zonca all the tests pass now.