Source code for skypy.power_spectrum._camb

import numpy as np
from astropy import units
from ._base import TabulatedPowerSpectrum


__all__ = [
    'CAMB',
]


class CAMB(TabulatedPowerSpectrum):
    '''CAMB linear matter power spectrum.
    Compute the linear matter power spectrum on a two dimensional grid of
    redshift and wavenumber using CAMB.
    '''

    def __init__(self, kmax, redshift, cosmology, A_s, n_s, **kwargs):

        try:
            from camb import CAMBparams, model, get_results
        except ImportError:
            raise Exception("camb is required to use skypy.power_spectrum.camb")

        h2 = cosmology.h * cosmology.h

        pars = CAMBparams()
        pars.set_cosmology(H0=cosmology.H0.value,
                           ombh2=cosmology.Ob0 * h2,
                           omch2=cosmology.Odm0 * h2,
                           omk=cosmology.Ok0,
                           TCMB=cosmology.Tcmb0.value,
                           mnu=np.sum(cosmology.m_nu.to_value(units.eV)),
                           standard_neutrino_neff=cosmology.Neff
                           )

        pars.InitPower.ns = n_s
        pars.InitPower.As = A_s
        pars.NonLinear = model.NonLinear_none
        k_per_logint, var1, var2, hubble_units, nonlinear = None, None, None, False, False
        pars.set_matter_power(redshifts=redshift, kmax=kmax, k_per_logint=k_per_logint, silent=True)
        results = get_results(pars)
        k, z, p = results.get_linear_matter_power_spectrum(var1, var2, hubble_units,
                                                           nonlinear=nonlinear)

        super().__init__(k*cosmology.h, z, p)