<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <html><head><meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1"> <title>division_scs.c Source File</title> <link href="doxygen.css" rel="stylesheet" type="text/css"> </head><body> <!-- Generated by Doxygen 1.2.15 --> <center> <a class="qindex" href="index.html">Main Page</a> <a class="qindex" href="annotated.html">Data Structures</a> <a class="qindex" href="files.html">File List</a> <a class="qindex" href="functions.html">Data Fields</a> <a class="qindex" href="globals.html">Globals</a> </center> <hr><h1>division_scs.c</h1><a href="division__scs_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre>00001 <font class="comment">/** Functions for SCS inverse and division</font> 00002 <font class="comment"></font> 00003 <font class="comment">@file division_scs.c</font> 00004 <font class="comment"></font> 00005 <font class="comment">@author Defour David David.Defour@ens-lyon.fr</font> 00006 <font class="comment">@author Florent de Dinechin Florent.de.Dinechin@ens-lyon.fr </font> 00007 <font class="comment"> </font> 00008 <font class="comment">This file is part of the SCS library.</font> 00009 <font class="comment"></font> 00010 <font class="comment"></font> 00011 <font class="comment">*/</font> 00012 00013 <font class="comment">/*</font> 00014 <font class="comment">Copyright (C) 2002 David Defour and Florent de Dinechin</font> 00015 <font class="comment"></font> 00016 <font class="comment"> This library is free software; you can redistribute it and/or</font> 00017 <font class="comment"> modify it under the terms of the GNU Lesser General Public</font> 00018 <font class="comment"> License as published by the Free Software Foundation; either</font> 00019 <font class="comment"> version 2.1 of the License, or (at your option) any later version.</font> 00020 <font class="comment"></font> 00021 <font class="comment"> This library is distributed in the hope that it will be useful,</font> 00022 <font class="comment"> but WITHOUT ANY WARRANTY; without even the implied warranty of</font> 00023 <font class="comment"> MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU</font> 00024 <font class="comment"> Lesser General Public License for more details.</font> 00025 <font class="comment"></font> 00026 <font class="comment"> You should have received a copy of the GNU Lesser General Public</font> 00027 <font class="comment"> License along with this library; if not, write to the Free Software</font> 00028 <font class="comment"> Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA</font> 00029 <font class="comment"></font> 00030 <font class="comment"> */</font> 00031 <font class="preprocessor">#include "<a class="code" href="scs_8h.html">scs.h</a>"</font> 00032 <font class="preprocessor">#include "<a class="code" href="scs__private_8h.html">scs_private.h</a>"</font> 00033 00034 00035 <font class="comment">/*</font> 00036 <font class="comment"> * Compute 1/x with a Newton scheme</font> 00037 <font class="comment"> */</font> <a name="l00038"></a><a class="code" href="division__scs_8c.html#a0">00038</a> <font class="keywordtype">void</font> <a class="code" href="division__scs_8c.html#a0">scs_inv</a>(<a class="code" href="structscs.html">scs_ptr</a> result, <a class="code" href="structscs.html">scs_ptr</a> x){ 00039 <a class="code" href="scs_8h.html#a3">scs_t</a> tmp, res, res1, scstwo; 00040 <font class="keywordtype">double</font> app_x, inv; 00041 00042 <a class="code" href="addition__scs_8c.html#a0">scs_set</a>(tmp, x); tmp->index = 0; <a class="code" href="scs2double_8c.html#a0">scs_get_d</a>(&app_x, tmp); 00043 00044 <a class="code" href="double2scs_8c.html#a1">scs_set_si</a>(scstwo, 2); 00045 <font class="comment">/* inv is a 53-bit approximation of 1/x */</font> 00046 inv = 1/app_x; 00047 00048 <a class="code" href="double2scs_8c.html#a0">scs_set_d</a>(res, inv); 00049 res->index -= x-><a class="code" href="structscs.html#m2">index</a>; 00050 00051 <font class="comment">/* First Newton Iteration */</font> 00052 <a class="code" href="multiplication__scs_8c.html#a2">scs_mul</a>(res1, x, res); 00053 <a class="code" href="addition__scs_8c.html#a9">scs_sub</a>(res1, scstwo, res1); 00054 <a class="code" href="multiplication__scs_8c.html#a2">scs_mul</a>(res, res, res1); 00055 00056 <font class="comment">/* Second Newton Iteration */</font> 00057 <a class="code" href="multiplication__scs_8c.html#a2">scs_mul</a>(res1, x, res); 00058 <a class="code" href="addition__scs_8c.html#a9">scs_sub</a>(res1, scstwo, res1); 00059 <a class="code" href="multiplication__scs_8c.html#a2">scs_mul</a>(result, res, res1); 00060 00061 <font class="keywordflow">return</font>; 00062 } 00063 00064 <font class="comment">/*</font> 00065 <font class="comment"> * Compute result = x/y; </font> 00066 <font class="comment"> */</font> <a name="l00067"></a><a class="code" href="division__scs_8c.html#a1">00067</a> <font class="keywordtype">void</font> <a class="code" href="division__scs_8c.html#a1">scs_div</a>(<a class="code" href="structscs.html">scs_ptr</a> result, <a class="code" href="structscs.html">scs_ptr</a> x, <a class="code" href="structscs.html">scs_ptr</a> y){ 00068 <a class="code" href="scs_8h.html#a3">scs_t</a> res; 00069 00070 <font class="keywordflow">if</font> (X_EXP != 1){ 00071 R_EXP = X_EXP / Y_EXP; 00072 <font class="keywordflow">return</font>; 00073 } 00074 00075 <a class="code" href="division__scs_8c.html#a0">scs_inv</a>(res, y); 00076 <a class="code" href="multiplication__scs_8c.html#a2">scs_mul</a>(result, res, x); 00077 <font class="keywordflow">return</font>; 00078 } </pre></div><hr><address align="right"><small>Generated on Tue Jun 17 10:15:51 2003 for SCSLib by <a href="http://www.doxygen.org/index.html"> <img src="doxygen.png" alt="doxygen" align="middle" border=0 width=110 height=53></a>1.2.15 </small></address> </body> </html>