Source code for pysm3.models.dust_realization

import numpy as np
import healpy as hp

from .. import units as u
from .. import utils
from .dust import ModifiedBlackBody


[docs]class ModifiedBlackBodyRealization(ModifiedBlackBody): def __init__( self, largescale_alm, freq_ref, amplitude_modulation_temp_alm, amplitude_modulation_pol_alm, small_scale_cl, largescale_alm_mbb_index, small_scale_cl_mbb_index, largescale_alm_mbb_temperature, small_scale_cl_mbb_temperature, nside, galplane_fix=None, seeds=None, synalm_lmax=None, has_polarization=True, map_dist=None, ): """Modified Black Body model with stochastic small scales Small scale fluctuations in the templates, the spectral index and the black body temperature are generated on the fly based on the input power spectra, then added to deterministic large scales. In order to reproduce `d10`, set seeds to [8192,777,888] and synalm_max to 16384, either by passing arguments to the class constructor or by creating a configuration file based on the `d11` parameters in `data/presets.cfg` uncommenting the final section labelled "Configuration for reproducing d10" Parameters ---------- largescale_alm, largescale_alm_mbb_index, largescale_alm_mbb_temperature: `pathlib.Path` Paths to the Alm expansion of the dust template IQU maps, the spectral index and the dust black-body temperature. Templates are assumed to be in logpoltens formalism, units refer to the unit of the maps when transformed back to IQU maps. freq_ref: Quantity or string Reference frequencies at which the intensity and polarization templates are defined. They should be a astropy Quantity object or a string (e.g. "1500 MHz") compatible with GHz. amplitude_modulation_temp_alm, amplitude_modulation_pol_alm: `pathlib.Path` Paths to the Alm expansion of the modulation maps used to rescale the small scales to make them more un-uniform, they are derived from highly smoothed input emission. small_scale_cl, small_scale_cl_mbb_index, small_scale_cl_mbb_temperature: `pathlib.Path` Paths to the power spectra of the small scale fluctuations for logpoltens iqu and the black body spectral index and temperature nside: int Resolution parameter at which this model is to be calculated. galplane_fix: `pathlib.Path` Set to None to skip the galactic plane fix in order to save some memory and computing time. Used to replace the galactic emission inside the GAL 070 Planck mask to a precomputed map. This is used to avoid excess power in the full sky spectra due to the generated small scales being too strong on the galactic plane. By default in d9,d10,d11 we use the input GNILC map with a resolution of 21.8' seeds: list of ints List of seeds used for generating the small scales, first is used for the template, the second for the spectral index, the third for the black body temperature. In order to reproduce `d10`, set them to [8192,777,888], if None, it uses random seeds. synalm_lmax: int Lmax of Synalm for small scales generation, by default it is 3*nside-1, with a maximum of 16384. In order to reproduce `d10`, you need to set it to 16834. map_dist: Map distribution Unsupported, this class doesn't support MPI Parallelization """ self.nside = nside assert nside is not None self.map_dist = map_dist self.has_polarization = has_polarization self.freq_ref_I = u.Quantity(freq_ref).to(u.GHz) self.freq_ref_P = self.freq_ref_I with u.set_enabled_equivalencies(u.cmb_equivalencies(self.freq_ref_I)): self.template_largescale_alm = self.read_alm( largescale_alm, has_polarization=self.has_polarization ).to(u.uK_RJ) self.modulate_alm = [ self.read_alm(each, has_polarization=False) for each in [ amplitude_modulation_temp_alm, amplitude_modulation_pol_alm, ] ] self.small_scale_cl = self.read_cl(small_scale_cl).to(u.uK_RJ ** 2) if galplane_fix is not None: self.galplane_fix_map = self.read_map( galplane_fix, field=(0, 1, 2, 3) ).value else: self.galplane_fix_map = None self.largescale_alm_mbb_index = self.read_alm( largescale_alm_mbb_index, has_polarization=False, ).to(u.dimensionless_unscaled) self.small_scale_cl_mbb_index = self.read_cl(small_scale_cl_mbb_index).to( u.dimensionless_unscaled ) self.largescale_alm_mbb_temperature = self.read_alm( largescale_alm_mbb_temperature, has_polarization=False ).to(u.K) self.small_scale_cl_mbb_temperature = self.read_cl( small_scale_cl_mbb_temperature ).to(u.K ** 2) self.nside = int(nside) ( self.I_ref, self.Q_ref, self.U_ref, self.mbb_index, self.mbb_temperature, ) = self.draw_realization(synalm_lmax, seeds)
[docs] def draw_realization(self, synalm_lmax=None, seeds=None): if seeds is None: seeds = (None, None, None) if synalm_lmax is None: synalm_lmax = min(16384, 3 * self.nside - 1) np.random.seed(seeds[0]) alm_small_scale = hp.synalm( list(self.small_scale_cl.value) + [np.zeros_like(self.small_scale_cl[0])] * 3, lmax=synalm_lmax, new=True, ) alm_small_scale = [ hp.almxfl(each, np.ones(min(synalm_lmax, 3 * self.nside - 1))) for each in alm_small_scale ] map_small_scale = hp.alm2map(alm_small_scale, nside=self.nside) # need later for beta, Td modulate_map_I = hp.alm2map(self.modulate_alm[0].value, self.nside) map_small_scale[0] *= modulate_map_I map_small_scale[1:] *= hp.alm2map(self.modulate_alm[1].value, self.nside) map_small_scale += hp.alm2map( self.template_largescale_alm.value, nside=self.nside, ) if self.galplane_fix_map is not None: map_small_scale *= hp.ud_grade(self.galplane_fix_map[3], self.nside) map_small_scale += hp.ud_grade( self.galplane_fix_map[:3] * (1 - self.galplane_fix_map[3]), self.nside ) output_IQU = ( utils.log_pol_tens_to_map(map_small_scale) * self.template_largescale_alm.unit ) * 0.911 # includes color correction # See https://github.com/galsci/pysm/issues/99 # Fixed values for comparison with d9 # mbb_index = 1.48 * u.dimensionless_unscaled # mbb_temperature = 19.6 * u.K output = {} for seed, key in zip(seeds[1:], ["mbb_index", "mbb_temperature"]): np.random.seed(seed) input_cl = getattr(self, f"small_scale_cl_{key}") output_unit = np.sqrt(1 * input_cl.unit).unit alm_small_scale = hp.synalm( input_cl.value, lmax=synalm_lmax, new=True, ) alm_small_scale = hp.almxfl( alm_small_scale, np.ones(min(3 * self.nside - 1, synalm_lmax + 1)) ) output[key] = hp.alm2map(alm_small_scale, nside=self.nside) * output_unit output[key] *= modulate_map_I output[key] += ( hp.alm2map( getattr(self, f"largescale_alm_{key}").value, nside=self.nside, ) * output_unit ) return ( output_IQU[0], output_IQU[1], output_IQU[2], output["mbb_index"], output["mbb_temperature"], )