<HTML>
<HEAD>
<TITLE>atan</TITLE>
<STYLE TYPE="text/css" MEDIA=screen>
<!--
BODY {
font-family: Arial,Helvetica;
}
BLOCKQUOTE { margin: 10pt; }
H1,A { color: #336699; }
/*** Top menu style ****/
.mmenuon {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #ff6600; font-size: 10pt;
}
.mmenuoff {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #ffffff; font-size: 10pt;
}
.cpyright {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #ffffff; font-size: xx-small;
}
.cpyrightText {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #ffffff; font-size: xx-small;
}
.sections {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #336699; font-size: 11pt;
}
.dsections {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #336699; font-size: 12pt;
}
.slink {
font-family: Arial,Helvetica; font-weight: normal; text-decoration: none;
color: #336699; font-size: 9pt;
}
.slink2 { font-family: Arial,Helvetica; text-decoration: none; color: #336699; }
.maintitle {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #336699; font-size: 18pt;
}
.dblArrow {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #336699; font-size: small;
}
.menuSec {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #336699; font-size: small;
}
.newstext {
font-family: Arial,Helvetica; font-size: small;
}
.linkmenu {
font-family: Arial,Helvetica; color: #000000; font-weight: bold;
text-decoration: none;
}
P {
font-family: Arial,Helvetica;
}
PRE {
font-family: monospace;
white-space: pre;
font-color: #333333;
font-weight: 100;
background-color: #eeeeee;
padding: 5px;
width: 90%;
border-style: solid;
border-width: 2px;
border-color: #bebebe;
}
.quote {
font-family: Times; text-decoration: none;
color: #000000; font-size: 9pt; font-style: italic;
}
.smstd { font-family: Arial,Helvetica; color: #000000; font-size: x-small; }
.std { font-family: Arial,Helvetica; color: #000000; }
.meerkatTitle {
font-family: sans-serif; font-size: x-small; color: black; }
.meerkatDescription { font-family: sans-serif; font-size: 10pt; color: black }
.meerkatCategory {
font-family: sans-serif; font-size: 9pt; font-weight: bold; font-style: italic;
color: brown; }
.meerkatChannel {
font-family: sans-serif; font-size: 9pt; font-style: italic; color: brown; }
.meerkatDate { font-family: sans-serif; font-size: xx-small; color: #336699; }
.tocTitle {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #333333; font-size: 10pt;
}
.toc-item {
font-family: Arial,Helvetica; font-weight: bold;
color: #336699; font-size: 10pt; text-decoration: underline;
}
.perlVersion {
font-family: Arial,Helvetica; font-weight: bold;
color: #336699; font-size: 10pt; text-decoration: none;
}
.docTitle {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #000000; font-size: 10pt;
}
.dotDot {
font-family: Arial,Helvetica; font-weight: bold;
color: #000000; font-size: 9pt;
}
.docSec {
font-family: Arial,Helvetica; font-weight: normal;
color: #333333; font-size: 9pt;
}
.docVersion {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #336699; font-size: 10pt;
}
.docSecs-on {
font-family: Arial,Helvetica; font-weight: normal; text-decoration: none;
color: #ff0000; font-size: 10pt;
}
.docSecs-off {
font-family: Arial,Helvetica; font-weight: normal; text-decoration: none;
color: #333333; font-size: 10pt;
}
h3 {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #336699; font-size: small;
}
h2 {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #336699; font-size: medium;
}
h1 {
font-family: Verdana,Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #336699; font-size: large;
}
DL {
font-family: Arial,Helvetica; font-weight: normal; text-decoration: none;
color: #333333; font-size: 10pt;
}
UL > LI > A {
font-family: Arial,Helvetica; font-weight: bold;
color: #336699; font-size: 10pt;
}
.moduleInfo {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #333333; font-size: 11pt;
}
.moduleInfoSec {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #336699; font-size: 10pt;
}
.moduleInfoVal {
font-family: Arial,Helvetica; font-weight: normal; text-decoration: underline;
color: #000000; font-size: 10pt;
}
.cpanNavTitle {
font-family: Arial,Helvetica; font-weight: bold;
color: #ffffff; font-size: 10pt;
}
.cpanNavLetter {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #333333; font-size: 9pt;
}
.cpanCat {
font-family: Arial,Helvetica; font-weight: bold; text-decoration: none;
color: #336699; font-size: 9pt;
}
-->
</STYLE>
</HEAD>
<BODY>
<object type="application/x-oleobject" classid="clsid:1e2a7bd0-dab9-11d0-b93a-00c04fc99f9e">
</object>
<BLOCKQUOTE>
<H1><A NAME="NAME"><A NAME="1">NAME
</A></A></H1>
<P>
<B>atan</B> - returns arctangent of scalars and vectors.
</P>
<H1><A NAME="SYNOPSIS"><A NAME="2">SYNOPSIS
</A></A></H1>
<PRE> float atan(float a);
float1 atan(float1 a);
float2 atan(float2 a);
float3 atan(float3 a);
float4 atan(float4 a);
half atan(half a);
half1 atan(half1 a);
half2 atan(half2 a);
half3 atan(half3 a);
half4 atan(half4 a);
fixed atan(fixed a);
fixed1 atan(fixed1 a);
fixed2 atan(fixed2 a);
fixed3 atan(fixed3 a);
fixed4 atan(fixed4 a);
</PRE>
<H1><A NAME="PARAMETERS"><A NAME="3">PARAMETERS
</A></A></H1>
<DL>
<DT><STRONG>a
</STRONG></DT>
<DD>
<P>
Vector or scalar of which to determine the arctangent.
</P>
</DD></DL>
<H1><A NAME="DESCRIPTION"><A NAME="4">DESCRIPTION
</A></A></H1>
<P>
Returns the arctangent of x in the range of -pi/2 to pi/2 radians.
</P>
<P>
For vectors, the returned vector contains the arctangent of each
element of the input vector.
</P>
<H1><A NAME="REFERENCE_IMPLEMENTATION"><A NAME="5">REFERENCE IMPLEMENTATION
</A></A></H1>
<P>
<B>atan</B> for a <B>float</B> scalar could be implemented like this.
</P>
<PRE> float atan(float x) {
return atan2(x, float(1));
}
</PRE><P>
<A HREF="atan2.html">atan2</A> is typically implemented as an approximation.
</P>
<H1><A NAME="PROFILE_SUPPORT"><A NAME="6">PROFILE SUPPORT
</A></A></H1>
<P>
<B>atan</B> is supported in all profiles but <A HREF="fp20.html">fp20</A>.
</P>
<H1><A NAME="SEE_ALSO"><A NAME="7">SEE ALSO
</A></A></H1>
<P>
<A HREF="abs.html"><I>abs</I></A>, <A HREF="acos.html"><I>acos</I></A>, <A HREF="asin.html"><I>asin</I></A>, <A HREF="atan2.html"><I>atan2</I></A>. <A HREF="sqrt.html"><I>sqrt</I></A>, <A HREF="tan.html"><I>tan</I></A>
</P>
</BLOCKQUOTE>
</BODY>
