# healpy.sphtfunc.synfast¶

healpy.sphtfunc.synfast(cls, nside, lmax=None, mmax=None, alm=False, pol=True, pixwin=False, fwhm=0.0, sigma=None, new=False, verbose=True)

Create a map(s) from cl(s).

Parameters
clsarray or tuple of array

A cl or a list of cl (either 4 or 6, see synalm())

nsideint, scalar

The nside of the output map(s)

lmaxint, scalar, optional

Maximum l for alm. Default: min of 3*nside-1 or length of the cls - 1

mmaxint, scalar, optional

Maximum m for alm.

almbool, scalar, optional

If True, return also alm(s). Default: False.

polbool, optional

If True, assumes input cls are TEB and correlation. Output will be TQU maps. (input must be 1, 4 or 6 cl’s) If False, fields are assumed to be described by spin 0 spherical harmonics. (input can be any number of cl’s) If there is only one input cl, it has no effect. Default: True.

pixwinbool, scalar, optional

If True, convolve the alm by the pixel window function. Default: False.

fwhmfloat, scalar, optional

The fwhm of the Gaussian used to smooth the map (applied on alm) [in radians]

sigmafloat, scalar, optional

The sigma of the Gaussian used to smooth the map (applied on alm) [in radians]

Returns
mapsarray or tuple of arrays

The output map (possibly list of maps if polarized input). or, if alm is True, a tuple of (map,alm) (alm possibly a list of alm if polarized input)

Notes

The order of the spectra will change in a future release. The new= parameter help to make the transition smoother. You can start using the new order by setting new=True. In the next version of healpy, the default will be new=True. This change is done for consistency between the different tools (alm2cl, synfast, anafast). In the new order, the spectra are ordered by diagonal of the correlation matrix. Eg, if fields are T, E, B, the spectra are TT, EE, BB, TE, EB, TB with new=True, and TT, TE, TB, EE, EB, BB if new=False.