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Functions
| NcXcor * | nc_xcor_new () |
| NcXcor * | nc_xcor_ref () |
| void | nc_xcor_free () |
| void | nc_xcor_clear () |
| NcXcorKinetic * | nc_xcor_kinetic_copy () |
| void | nc_xcor_kinetic_free () |
| void | nc_xcor_prepare () |
| void | nc_xcor_limber () |
Properties
| NcDistance * | distance | Read / Write / Construct Only |
| NcXcorLimberMethod | meth | Read / Write / Construct |
| NcmPowspec * | power-spec | Read / Write / Construct Only |
Description
The angular power spectrum between observables $A$ and $B$ with kernels $W^A$ and $W^B$ is \begin{equation} C_{\ell}^{AB} &= \int dz W^A(z) \int dz^\prime W^B (z^\prime) \times \int dk \frac{2}{\pi} k^2 P(k, z, z^\prime) j_{\ell}(k\chi(z)) j_{\ell} (k\chi(z^\prime)). \end{equation} In the Limber approximation, it reduces to \begin{equation} C_{\ell}^{AB} = \int_0^{z_*} dz \frac{H(z)}{c \chi^2(z)} W^A(z) W^B (z) P\left(k = \frac{\ell +1/2}{\chi(z)} , z \right), \end{equation} where $P\left(k = \frac{\ell +1/2}{\chi(z)} , z \right)$ is the power spectrum (a NcmPowspec) at redshift $z$ and $chi(z)$ the comoving distance (a NcDistance).
Functions
nc_xcor_new ()
NcXcor * nc_xcor_new (NcDistance *dist,NcmPowspec *ps,NcXcorLimberMethod meth);
Two methods are available to compute Limber-approximated integrals: independent GSL numerical integration or vector integration using Sundials's CVode algorithm.
nc_xcor_limber ()
void nc_xcor_limber (NcXcor *xc,NcXcorLimberKernel *xclk1,NcXcorLimberKernel *xclk2,NcHICosmo *cosmo,guint lmin,guint lmax,NcmVector *vp);
Performs the computation of the power spectrum $C_{\ell}^{AB}$ in the Limber approximation. The kernels of observables A and B are xclk1
and xclk2
. If xclk2
is NULL, the auto power spectrum is computed. The result for multipoles lmin to lmax (included) is stored in the NcmVector vp
.
Property Details
The “distance” property
“distance” NcDistance *
This property keeps the distance object.
Owner: NcXcor
Flags: Read / Write / Construct Only
The “meth” property
“meth” NcXcorLimberMethod
This property keeps the method enumerator to compute the integrals.
Owner: NcXcor
Flags: Read / Write / Construct
Default value: NC_XCOR_LIMBER_METHOD_GSL
The “power-spec” property
“power-spec” NcmPowspec *
This property keeps the matter power spectrum object.
Owner: NcXcor
Flags: Read / Write / Construct Only