Method

NumCosmoMathSphereMapcompute_cross_Cl

Declaration [src]

NcmVector*
ncm_sphere_map_compute_cross_Cl (
  NcmSphereMap* smap1,
  NcmSphereMap* smap2
)

Description [src]

Computes the cross-spectrum between two maps: $$C_\ell^\mathrm{cross} = \frac{1}{2\ell+1} \sum_{m=-\ell}^\ell \mathrm{Re}(a_{lm}^{(1)} \bar{a}_{lm}^{(2)})$$

Both maps must have their spherical harmonic coefficients already computed via ncm_sphere_map_prepare_alm(), and must have the same lmax and nside.

Parameters

smap2

Type: NcmSphereMap

Second NcmSphereMap with computed $a_{lm}$.

The data is owned by the caller of the method.

Return value

Type: NcmVector

A NcmVector containing the cross-spectrum $C_\ell$ for $\ell = 0, \ldots, \ell_\mathrm{max}$.

The caller of the method takes ownership of the returned data, and is responsible for freeing it.