Source code for pysm3.models.power_law

import numpy as np
from .. import units as u
from numba import njit
from .. import utils

from .template import Model


[docs]class PowerLaw(Model): """ This is a model for a simple power law synchrotron model. """ def __init__( self, map_I, freq_ref_I, map_pl_index, nside, map_Q=None, map_U=None, freq_ref_P=None, unit_I=None, unit_Q=None, unit_U=None, map_dist=None, ): """ This function initialzes the power law model of synchrotron emission. The initialization of this model consists of reading in emission templates from file, reading in spectral parameter maps from file. Parameters ---------- map_I, map_Q, map_U: `pathlib.Path` object Paths to the maps to be used as I, Q, U templates. unit_* : string or Unit Unit string or Unit object for all input FITS maps, if None, the input file should have a unit defined in the FITS header. freq_ref_I, freq_ref_P: 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. map_pl_index: `pathlib.Path` object Path to the map to be used as the power law index. nside: int Resolution parameter at which this model is to be calculated. """ super().__init__(nside, map_dist=map_dist) # do model setup self.I_ref = self.read_map(map_I, unit=unit_I) # This does unit conversion in place so we do not copy the data # we do not keep the original unit because otherwise we would need # to make a copy of the array when we run the model self.I_ref <<= u.uK_RJ self.freq_ref_I = u.Quantity(freq_ref_I).to(u.GHz) self.has_polarization = map_Q is not None if self.has_polarization: self.Q_ref = self.read_map(map_Q, unit=unit_Q) self.Q_ref <<= u.uK_RJ self.U_ref = self.read_map(map_U, unit=unit_U) self.U_ref <<= u.uK_RJ self.freq_ref_P = u.Quantity(freq_ref_P).to(u.GHz) try: # input is a number self.pl_index = u.Quantity(map_pl_index, unit="") except TypeError: # input is a path self.pl_index = self.read_map(map_pl_index, unit="") return
[docs] @u.quantity_input def get_emission(self, freqs: u.GHz, weights=None): freqs = utils.check_freq_input(freqs) weights = utils.normalize_weights(freqs, weights) if not self.has_polarization: outputs = ( get_emission_numba_IQU( freqs, weights, self.I_ref.value, None, None, self.freq_ref_I.value, None, self.pl_index.value, ) << u.uK_RJ ) else: outputs = ( get_emission_numba_IQU( freqs, weights, self.I_ref.value, self.Q_ref.value, self.U_ref.value, self.freq_ref_I.value, self.freq_ref_P.value, self.pl_index.value, ) << u.uK_RJ ) return outputs
@njit(parallel=True) def get_emission_numba_IQU( freqs, weights, I_ref, Q_ref, U_ref, freq_ref_I, freq_ref_P, pl_index ): has_pol = Q_ref is not None output = np.zeros((3, len(I_ref)), dtype=I_ref.dtype) I, Q, U = 0, 1, 2 for i, (freq, weight) in enumerate(zip(freqs, weights)): utils.trapz_step_inplace( freqs, weights, i, I_ref * (freq / freq_ref_I) ** pl_index, output[I] ) if has_pol: pol_scaling = (freq / freq_ref_P) ** pl_index utils.trapz_step_inplace(freqs, weights, i, Q_ref * pol_scaling, output[Q]) utils.trapz_step_inplace(freqs, weights, i, U_ref * pol_scaling, output[U]) return output
[docs]class CurvedPowerLaw(PowerLaw): def __init__( self, map_I, freq_ref_I, map_pl_index, nside, spectral_curvature, freq_curve, map_Q=None, map_U=None, freq_ref_P=None, unit_I=None, unit_Q=None, unit_U=None, map_dist=None, ): super().__init__( map_I=map_I, freq_ref_I=freq_ref_I, map_pl_index=map_pl_index, nside=nside, map_Q=map_Q, map_U=map_U, freq_ref_P=freq_ref_P, unit_I=unit_I, unit_Q=unit_Q, unit_U=unit_U, map_dist=map_dist, ) try: # input is a number self.spectral_curvature = u.Quantity(spectral_curvature, unit="") except TypeError: # input is a path self.spectral_curvature = self.read_map(spectral_curvature, unit="") self.freq_curve = u.Quantity(freq_curve).to(u.GHz)
[docs] @u.quantity_input def get_emission(self, freqs: u.GHz, weights=None): freqs = utils.check_freq_input(freqs) weights = utils.normalize_weights(freqs, weights) if not self.has_polarization: outputs = ( get_emission_numba_IQU_curved( freqs, weights, self.I_ref.value, None, None, self.freq_ref_I.value, None, self.pl_index.value, self.freq_curve.value, self.spectral_curvature.value, ) << u.uK_RJ ) else: outputs = ( get_emission_numba_IQU_curved( freqs, weights, self.I_ref.value, self.Q_ref.value, self.U_ref.value, self.freq_ref_I.value, self.freq_ref_P.value, self.pl_index.value, self.freq_curve.value, self.spectral_curvature.value, ) << u.uK_RJ ) return outputs
@njit(parallel=True) def get_emission_numba_IQU_curved( freqs, weights, I_ref, Q_ref, U_ref, freq_ref_I, freq_ref_P, pl_index, freq_curve, curvature, ): has_pol = Q_ref is not None output = np.zeros((3, len(I_ref)), dtype=I_ref.dtype) I, Q, U = 0, 1, 2 for i, (freq, weight) in enumerate(zip(freqs, weights)): curvature_term = np.log((freq / freq_curve) ** curvature) utils.trapz_step_inplace( freqs, weights, i, I_ref * (freq / freq_ref_I) ** (pl_index + curvature_term), output[I], ) if has_pol: pol_scaling = (freq / freq_ref_P) ** (pl_index + curvature_term) utils.trapz_step_inplace(freqs, weights, i, Q_ref * pol_scaling, output[Q]) utils.trapz_step_inplace(freqs, weights, i, U_ref * pol_scaling, output[U]) return output