The function to convert \(D_{l}\) to \(C_{l}\) i.e.
\[C_{l} = D_{l}2\pi/l(l+1)\]
- Parameters:
dl (np.ndarray, 1d-array) – Power spectrum
ell_start (int, default = 2) – The multi-pole ell value of first index of the \(D_{l}\).
- Returns:
cl (np.ndarray,1d-array)