transformcl.cltocorr

transformcl.cltocorr(cl, closed=False)

transform angular power spectrum to correlation function

Takes an angular power spectrum with \(\mathtt{n} = \mathtt{lmax}+1\) coefficients and returns the corresponding angular correlation function in \(\mathtt{n}\) points.

The correlation function values can be computed either over the closed interval \([0, \pi]\), in which case \(\theta_0 = 0\) and \(\theta_{n-1} = \pi\), or over the open interval \((0, \pi)\).

Parameters:
cl(n,) array_like

Angular power spectrum from \(0\) to \(\mathtt{lmax}\).

closedbool

Compute correlation function over open (closed=False) or closed (closed=True) interval.

Returns:
corr(n,) array_like

Angular correlation function.

See also

transformcl.corrtocl

the inverse operation

transformcl.theta

compute the angles at which the correlation function is evaluated

Notes

The computation uses the inverse discrete Legendre transform flt.idlt().