nside2ntemplates


This IDL facility provides the number of template pixels Ntemplates corresponding to resolution parameter Nside. Each template pixel has a different shape that can not be matched (by rotation or reflexion) to that of any of the other templates.

Location in HEALPix directory tree: src/idl/toolkit/nside2ntemplates.pro 


FORMAT

IDL> Ntemplates=NSIDE2NTEMPLATES (Nside[,ERROR=])


QUALIFIERS

Nside
HEALPix resolution parameter (scalar integer), should be a valid Nside (power of 2 in $\{1,\ldots,8192\}$)
Ntemplates
number of templates


KEYWORDS

ERROR=
error flag, set to 1 on output if Nside is NOT valid, or stays to 0 otherwise.


DESCRIPTION

nside2ntemplates outputs the number of template pixels

\begin{displaymath}N_{\rm template}=\frac{1+N_{\rm side}(N_{\rm side}+6)}{4}.\end{displaymath}

If the argument $N_{\rm side}$ is not valid, a warning is issued and the error flag is raised.


RELATED ROUTINES

This section lists the routines related to nside2ntemplates

idl
version 6.4 or more is necessary to run nside2ntemplates .
template_pixel_ring
template_pixel_nest
return the template pixel associated with any HEALPix pixel
same_shape_pixels_ring
same_shape_pixels_nest
return the ordered list of pixels having the same shape as a given pixel template


EXAMPLE:

Ntemplates = nside2ntemplates(256, ERROR=error)
Ntemplates will be 16768 the number of template pixels for the HEALPix resolution parameter 256 and error will be 0

Version 3.31, 2017-01-06