1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"> 2 3<!--Converted with LaTeX2HTML 2018.3 (Released July 19, 2018) --> 4<HTML lang="EN"> 5<HEAD> 6<TITLE>nside2npix</TITLE> 7<META NAME="description" CONTENT="nside2npix"> 8<META NAME="keywords" CONTENT="csub"> 9<META NAME="resource-type" CONTENT="document"> 10<META NAME="distribution" CONTENT="global"> 11 12<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=utf-8"> 13<META NAME="viewport" CONTENT="width=device-width, initial-scale=1.0"> 14<META NAME="Generator" CONTENT="LaTeX2HTML v2018.3"> 15 <link rel='apple-touch-icon' sizes='180x180' href='images/favicons/apple-touch-icon.png?v=2017'> 16 <link rel='icon' type='image/png' sizes='32x32' href='images/favicons/favicon-32x32.png?v=2017'> 17 <link rel='icon' type='image/png' sizes='16x16' href='images/favicons/favicon-16x16.png?v=2017'> 18 <link rel='manifest' href='images/favicons/manifest.json?v=2017'> 19 <link rel='mask-icon' href='images/favicons/safari-pinned-tab.svg?v=2017' color='#5bbad5'> 20 <link rel='shortcut icon' href='images/favicons/favicon.ico?v=2017'> 21 <meta name='apple-mobile-web-app-title' content='HEALPix'> 22 <meta name='application-name' content='HEALPix'> 23 <meta name='msapplication-config' content='images/favicons/browserconfig.xml?v=2017'> 24 <meta name='theme-color' content='#ffffff'> 25 26<LINK REL="STYLESHEET" HREF="csub.css"> 27 28<LINK REL="next" HREF="csub_pix2xxx_ang2xxx_vec2xxx_nes.htm"> 29<LINK REL="previous" HREF="csub_npix2nside.htm"> 30<LINK REL="next" HREF="csub_pix2xxx_ang2xxx_vec2xxx_nes.htm"> 31</HEAD> 32 33<body text="#000000" bgcolor="#FFFFFA"> 34 35<DIV CLASS="navigation"><!--Navigation Panel--> 36<A 37 HREF="csub_npix2nside.htm"> 38<IMG WIDTH="63" HEIGHT="24" ALT="previous" SRC="prev.png"></A> 39<A 40 HREF="csub_HEALPix_C_subroutines.htm"> 41<IMG WIDTH="26" HEIGHT="24" ALT="up" SRC="up.png"></A> 42<A 43 HREF="csub_pix2xxx_ang2xxx_vec2xxx_nes.htm"> 44<IMG WIDTH="37" HEIGHT="24" ALT="next" SRC="next.png"></A> 45<A ID="tex2html46" 46 HREF="csub_Contents.htm"> 47<IMG WIDTH="65" HEIGHT="24" ALT="contents" SRC="contents.png"></A> 48<BR> 49<B> Previous:</B> <A 50 HREF="csub_npix2nside.htm">npix2nside</A> 51 52<B>Up:</B> <A 53 HREF="csub_HEALPix_C_subroutines.htm">HEALPix/C subroutines</A> 54 55<B> Next:</B> <A 56 HREF="csub_pix2xxx_ang2xxx_vec2xxx_nes.htm">pix2xxx, ang2xxx, vec2xxx, nest2ring, ring2nest</A> 57<B> Top:</B> <a href="main.htm">Main Page</a></DIV> 58<!--End of Navigation Panel--> 59 60<H1><A ID="SECTION900"></A> 61<A ID="csub:nside2npix"></A> 62<BR> 63 64</H1> 65 66<P> 67<b><font size=+6><FONT COLOR="#CC0000">nside2npix</FONT></font></b><hr> 68<H3>Function to provide the number of pixels <!-- MATH 69 $N_{\mathrm{pix}}$ 70 --> 71<SPAN CLASS="MATH"><I>N</I><SUB>pix</SUB></SPAN> over the full sky corresponding 72to resolution parameter <!-- MATH 73 $N_{\mathrm{side}}$ 74 --> 75<SPAN CLASS="MATH"><I>N</I><SUB>side</SUB></SPAN>. 76</H3> 77Location in HEALPix directory tree: <a href="https://sourceforge.net/p/healpix/code/1005/tree/trunk/src/C/subs/chealpix.c"><b>src/C/subs/chealpix.c</b></a> 78 79<P> 80<hr><h1>FORMAT </h1><h3> 81long nside2npix(const long nside) 82</h3> 83 84<P> 85<hr><H1>ARGUMENTS</H1> 86 87<TABLE CELLPADDING=3 BORDER="1"> 88<TR><TH ALIGN="LEFT" VALIGN="TOP" WIDTH=150><SPAN CLASS="textbf">name&dimensionality</SPAN></TH> 89<TH ALIGN="LEFT" VALIGN="TOP" WIDTH=25><SPAN CLASS="textbf">kind</SPAN></TH> 90<TH ALIGN="LEFT" VALIGN="TOP" WIDTH=50><SPAN CLASS="textbf">in/out</SPAN></TH> 91<TH ALIGN="LEFT" VALIGN="TOP" WIDTH=225><SPAN CLASS="textbf">description</SPAN></TH> 92</TR> 93<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=150> </TD> 94<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=25> </TD> 95<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=50> </TD> 96<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=225> </TD> 97</TR> 98<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=150> 99nside</TD> 100<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=25>long</TD> 101<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=50>IN</TD> 102<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=225>the <!-- MATH 103 $N_{\mathrm{side}}$ 104 --> 105<SPAN CLASS="MATH"><I>N</I><SUB>side</SUB></SPAN> parameter of the map.</TD> 106</TR> 107<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=150><FONT COLOR="#CC0000">nside2npix</FONT></TD> 108<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=25>long</TD> 109<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=50>OUT</TD> 110<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=225>returns the number of pixels <!-- MATH 111 $N_{\mathrm{pix}}$ 112 --> 113<SPAN CLASS="MATH"><I>N</I><SUB>pix</SUB></SPAN> of the map <!-- MATH 114 $N_{\mathrm{pix}}=12N_{\mathrm{side}}^2$ 115 --> 116<SPAN CLASS="MATH"><I>N</I><SUB>pix</SUB>=12<I>N</I><SUB>side</SUB><SUP><i>2</i></SUP></SPAN>.</TD> 117</TR> 118</TABLE> 119 120<P> 121<HR><H1>EXAMPLE:</H1> 122<tt>npix= nside2npix(256); 123<BR></tt> 124<blockquote> 125Returns the number of <b>HEALPix</b> pixels (786432) for the resolution 126parameter 256. 127</blockquote> 128 129<P> 130<hr><H1>RELATED ROUTINES</H1><h3>This section lists the routines related to <b><FONT COLOR="#CC0000">nside2npix</FONT></b></h3> 131 132 <DL COMPACT><DT> 133<B><A HREF="csub_ang2vec.htm#csub:ang2vec">ang2vec</A></B> 134<DD>converts <SPAN CLASS="MATH"><IMG STYLE="height: 2.33ex; vertical-align: -0.68ex; " SRC="csub_img5.png" 135 ALT="$(\theta,\phi) $"></SPAN> spherical coordinates into <SPAN CLASS="MATH">(<I>x</I>,<I>y</I>,<I>z</I>)</SPAN> cartesian coordinates. 136 <DT> 137<B><A HREF="csub_vec2ang.htm#csub:vec2ang">vec2ang</A></B> 138<DD>converts <SPAN CLASS="MATH">(<I>x</I>,<I>y</I>,<I>z</I>)</SPAN> cartesian coordinates into <SPAN CLASS="MATH"><IMG STYLE="height: 2.33ex; vertical-align: -0.68ex; " SRC="csub_img5.png" 139 ALT="$(\theta,\phi) $"></SPAN> spherical coordinates. 140<DT> 141<B><A HREF="csub_npix2nside.htm#csub:npix2nside">npix2nside</A></B> 142<DD>converts <!-- MATH 143 $N_{\mathrm{side}}$ 144 --> 145<SPAN CLASS="MATH"><I>N</I><SUB>side</SUB></SPAN> into number of 146full sky pixels <!-- MATH 147 $N_{\mathrm{pix}}$ 148 --> 149<SPAN CLASS="MATH"><I>N</I><SUB>pix</SUB></SPAN>. 150 </DL> 151 152<P> 153 154 155<P> 156 157<P> 158 159<DIV CLASS="navigation"><HR> 160<!--Navigation Panel--> 161<A 162 HREF="csub_npix2nside.htm"> 163<IMG WIDTH="63" HEIGHT="24" ALT="previous" SRC="prev.png"></A> 164<A 165 HREF="csub_HEALPix_C_subroutines.htm"> 166<IMG WIDTH="26" HEIGHT="24" ALT="up" SRC="up.png"></A> 167<A 168 HREF="csub_pix2xxx_ang2xxx_vec2xxx_nes.htm"> 169<IMG WIDTH="37" HEIGHT="24" ALT="next" SRC="next.png"></A> 170<A ID="tex2html46" 171 HREF="csub_Contents.htm"> 172<IMG WIDTH="65" HEIGHT="24" ALT="contents" SRC="contents.png"></A> 173<BR> 174<B> Previous:</B> <A 175 HREF="csub_npix2nside.htm">npix2nside</A> 176 177<B>Up:</B> <A 178 HREF="csub_HEALPix_C_subroutines.htm">HEALPix/C subroutines</A> 179 180<B> Next:</B> <A 181 HREF="csub_pix2xxx_ang2xxx_vec2xxx_nes.htm">pix2xxx, ang2xxx, vec2xxx, nest2ring, ring2nest</A> 182<B> Top:</B> <a href="main.htm">Main Page</a></DIV> 183<!--End of Navigation Panel--> 184<ADDRESS> 185Version 3.50, 2018-12-10 186</ADDRESS> 187</BODY> 188</HTML> 189
