zbounds2scan

subroutine zbounds2scan( double zbounds[2], pixeltype pixelization, scandef *scan)

Purpose:

The routine allocates and defines the S2HAT scandef structure, scan, corresponding to the observed (azimuthally symmetric) part of the sky defined by two cosines of the polar angles as stored in zbounds.

The scan structure has to be defined and identical on all the employed processors prior to any call to the transform routines. This can be achieved by calling the routine by either all procs or just one proc, e.g., root, followed by a call to mpi_scanbcast.

The routine mask2scan provides a more general and flexible way of defining, zbounds2scan is a quick and easy alternative, which is however more limited in scope.

Parameters:

input:

zbounds- [double], a two-component vector defining the iso-latitude sky cut to be performed on the map prior to computing a spherical transform (see Healpix manual);

pixelization- [type(pixeltype)], a S2HAT structure defining all the properties of the pixelization;

output:

scan- [type(scandef)], a S2HAT structure containing all the info about the sky coverage needed by the transforms.