lib.survey_selection.window_convolution.wigner3j_square

lib.survey_selection.window_convolution.wigner3j_square(ellout, ellin, prefactor=True)

Return the coefficients corresponding to the product of two Legendre polynomials, corresponding to \(C_{\ell \ell^{\prime} L}\) of e.g. arXiv:2106.06324 eq. 2.2, with \(\ell\) corresponding to projout.proj and \(\ell^{\prime}\) to projin.proj.

Parameters

• ellout (int) – Output order.

• ellin (int) – Input order.

• prefactor (bool, default=True) – Whether to include prefactor \((2 \ell + 1)/(2 \ell^{\prime} + 1)\) for window convolution.

Returns

• ells (list) – List of mulipole orders.

• coeffs (list) – List of corresponding window coefficients.