PrecomputedAlms¶
- class so_pysm_models.PrecomputedAlms(filename, input_units='uK_CMB', input_reference_frequency=None, nside=None, target_shape=None, target_wcs=None, from_cl=False, from_cl_seed=None, precompute_output_map=True, has_polarization=True, map_dist=None)[source] [edit on github]¶
Bases:
object
Generic component based on Precomputed Alms
Load a set of Alms from a FITS file and generate maps at the requested resolution and frequency assuming the CMB black body spectrum. A single set of Alms is used for all frequencies requested by PySM, consider that PySM expects the output of components to be in uK_RJ. See more details at https://so-pysm-models.readthedocs.io/en/latest/so_pysm_models/models.html
Also note that the Alms are clipped to 3*nside-1 to avoid artifacts from high-ell components which cannot be properly represented by a low-nside map.
- Parameters
- filenamestring
Path to the input Alms in FITS format
- input_unitsstring
Input unit strings as defined by pysm.convert_units, e.g. K_CMB, uK_RJ, MJysr
- input_reference_frequency: float
If input units are K_RJ or Jysr, the reference frequency
- nsideint
HEALPix NSIDE of the output maps
- from_clbool
If True, the input file contains C_ell instead of a_lm, they should provided with the healpy old ordering TT, TE, TB, EE, EB, BB, sorry.
- from_cl_seedint
Seed set just before synalm to simulate the alms from the C_ell, necessary to set it in order to get the same input map for different runs only used if
from_cl
is True- precompute_output_mapbool
If True (default), Alms are transformed into a map in the constructor, if False, the object only stores the Alms and generate the map at each call of the signal method, this is useful to generate maps convolved with different beams
- has_polarizationbool
whether or not to simulate also polarization maps Default: True
Methods Summary
compute_output_map
(alm)get_emission
(freqs[, fwhm, weights, ...])Return map in uK_RJ at given frequency or array of frequencies
Methods Documentation
- compute_output_map(alm)[source] [edit on github]¶
- get_emission(freqs: Unit('GHz'), fwhm: [Unit('arcmin'), None] = None, weights=None, output_units=Unit('uK_RJ'))[source] [edit on github]¶
Return map in uK_RJ at given frequency or array of frequencies
- Parameters
- freqslist or ndarray
Frequency or frequencies in GHz at which compute the signal
- fwhmfloat (optional)
Smooth the input alms before computing the signal, this can only be used if the class was initialized with
precompute_output_map
to False.- output_unitsstr
Output units, as defined in
pysm.convert_units
, by default this is “uK_RJ” as expected by PySM.- Returns
- ——-
- output_mapsndarray
Output maps array with the shape (num_freqs, 1 or 3 (I or IQU), npix)