Compute Gaia TGE n_pix with nside2npix - #73
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healpix_level is stored as int8. 4**level then overflows for every realistic TGE resolution, so the optimum map is empty and a nest index raises IndexError. Use the HEALPix identity nside2npix(2**int(level)).
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Description
GaiaTGEQuerystoreshealpix_levelasi1. On the optimum path it setsNumPy keeps that power in int8, so
4**8(and every realistic TGE level ≥ 4) overflows to 0. The index array is then empty and a nest index such as 19200 raisesIndexError.The HEALPix identity is
n_pix = nside2npix(2**level) = 12 * 4**level. Rewriting that with a Pythonintlevel keeps the map size finite. The on-disk dtype and the nest fill loop are unchanged.Measured current
n_pixfor int8 levels 6, 7, 8, 9 is 0; this change is 49152, 196608, 786432, 3145728.Related issues
Closes #70