<HTML> <HEAD> <TITLE>log</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; 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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>log</B> - returns the natural logarithm of scalars and vectors </P> <H1><A NAME="SYNOPSIS"><A NAME="2">SYNOPSIS </A></A></H1> <PRE> float log(float a); float1 log(float1 a); float2 log(float2 a); float3 log(float3 a); float4 log(float4 a); half log(half a); half1 log(half1 a); half2 log(half2 a); half3 log(half3 a); half4 log(half4 a); fixed log(fixed a); fixed1 log(fixed1 a); fixed2 log(fixed2 a); fixed3 log(fixed3 a); fixed4 log(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 natural logarithm. </P> </DD></DL> <H1><A NAME="DESCRIPTION"><A NAME="4">DESCRIPTION </A></A></H1> <P> Returns the natural logarithm <I>a</I>. </P> <P> For vectors, the returned vector contains the natural logarithm of each element of the input vector. </P> <H1><A NAME="REFERENCE_IMPLEMENTATION"><A NAME="5">REFERENCE IMPLEMENTATION </A></A></H1> <PRE> float3 log(float3 a) { float3 rv; int i; for (i=0; i<3; i++) { rv[i] = log(a[i]); // this is the ANSI C standard library log() } return rv; } </PRE><P> <B>log</B> is typically implemented with a native base-2 logarithm instruction. </P> <H1><A NAME="PROFILE_SUPPORT"><A NAME="6">PROFILE SUPPORT </A></A></H1> <P> <B>log</B> is fully supported in all profiles unless otherwise specified. </P> <P> Support in the <A HREF="fp20.html">fp20</A> is limited to constant compile-time evaluation. </P> <H1><A NAME="SEE_ALSO"><A NAME="7">SEE ALSO </A></A></H1> <P> <A HREF="exp.html"><I>exp</I></A>, <A HREF="log10.html"><I>log10</I></A>, <A HREF="log2.html"><I>log2</I></A>, <A HREF="pow.html"><I>pow</I></A> </P> </BLOCKQUOTE> </BODY>