<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html><head><meta http-equiv="Content-Type" content="text/html;charset=UTF-8"> <title>SuperLU: SRC/sgsequ.c File Reference</title> <link href="doxygen.css" rel="stylesheet" type="text/css"> <link href="tabs.css" rel="stylesheet" type="text/css"> </head><body> <!-- Generated by Doxygen 1.5.5 --> <div class="navigation" id="top"> <div class="tabs"> <ul> <li><a href="index.html"><span>Main Page</span></a></li> <li><a href="annotated.html"><span>Data Structures</span></a></li> <li class="current"><a href="files.html"><span>Files</span></a></li> </ul> </div> </div> <div class="contents"> <h1>SRC/sgsequ.c File Reference</h1>Computes row and column scalings. <a href="#_details">More...</a> <p> <code>#include <math.h></code><br> <code>#include "<a class="el" href="slu__sdefs_8h-source.html">slu_sdefs.h</a>"</code><br> <table border="0" cellpadding="0" cellspacing="0"> <tr><td></td></tr> <tr><td colspan="2"><br><h2>Functions</h2></td></tr> <tr><td class="memItemLeft" nowrap align="right" valign="top">void </td><td class="memItemRight" valign="bottom"><a class="el" href="sgsequ_8c.html#d8a808e807e38c32c08cfbeadb088f08">sgsequ</a> (<a class="el" href="structSuperMatrix.html">SuperMatrix</a> *<a class="el" href="ilu__zdrop__row_8c.html#c900805a486cbb8489e3c176ed6e0d8e">A</a>, float *r, float *c, float *rowcnd, float *colcnd, float *amax, int *info)</td></tr> <tr><td class="mdescLeft"> </td><td class="mdescRight">Driver related. <a href="#d8a808e807e38c32c08cfbeadb088f08"></a><br></td></tr> </table> <hr><a name="_details"></a><h2>Detailed Description</h2> <pre> -- SuperLU routine (version 2.0) -- Univ. of California Berkeley, Xerox Palo Alto Research Center, and Lawrence Berkeley National Lab. November 15, 1997</pre><p> <pre> Modified from LAPACK routine SGEEQU </pre> <hr><h2>Function Documentation</h2> <a class="anchor" name="d8a808e807e38c32c08cfbeadb088f08"></a><!-- doxytag: member="sgsequ.c::sgsequ" ref="d8a808e807e38c32c08cfbeadb088f08" args="(SuperMatrix *A, float *r, float *c, float *rowcnd, float *colcnd, float *amax, int *info)" --> <div class="memitem"> <div class="memproto"> <table class="memname"> <tr> <td class="memname">void sgsequ </td> <td>(</td> <td class="paramtype"><a class="el" href="structSuperMatrix.html">SuperMatrix</a> * </td> <td class="paramname"> <em>A</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">float * </td> <td class="paramname"> <em>r</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">float * </td> <td class="paramname"> <em>c</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">float * </td> <td class="paramname"> <em>rowcnd</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">float * </td> <td class="paramname"> <em>colcnd</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">float * </td> <td class="paramname"> <em>amax</em>, </td> </tr> <tr> <td class="paramkey"></td> <td></td> <td class="paramtype">int * </td> <td class="paramname"> <em>info</em></td><td> </td> </tr> <tr> <td></td> <td>)</td> <td></td><td></td><td width="100%"></td> </tr> </table> </div> <div class="memdoc"> <p> <pre> Purpose =======</pre><p> <pre> SGSEQU computes row and column scalings intended to equilibrate an M-by-N sparse matrix A and reduce its condition number. R returns the row scale factors and C the column scale factors, chosen to try to make the largest element in each row and column of the matrix B with elements B(i,j)=R(i)*A(i,j)*C(j) have absolute value 1.</pre><p> <pre> R(i) and C(j) are restricted to be between SMLNUM = smallest safe number and BIGNUM = largest safe number. Use of these scaling factors is not guaranteed to reduce the condition number of A but works well in practice.</pre><p> <pre> See <a class="el" href="supermatrix_8h.html" title="Defines matrix types.">supermatrix.h</a> for the definition of 'SuperMatrix' structure.</pre><p> <pre> Arguments =========</pre><p> <pre> A (input) SuperMatrix* The matrix of dimension (A->nrow, A->ncol) whose equilibration factors are to be computed. The type of A can be: Stype = SLU_NC; Dtype = SLU_S; Mtype = SLU_GE.</pre><p> <pre> R (output) float*, size A->nrow If INFO = 0 or INFO > M, R contains the row scale factors for A.</pre><p> <pre> C (output) float*, size A->ncol If INFO = 0, C contains the column scale factors for A.</pre><p> <pre> ROWCND (output) float* If INFO = 0 or INFO > M, ROWCND contains the ratio of the smallest R(i) to the largest R(i). If ROWCND >= 0.1 and AMAX is neither too large nor too small, it is not worth scaling by R.</pre><p> <pre> COLCND (output) float* If INFO = 0, COLCND contains the ratio of the smallest C(i) to the largest C(i). If COLCND >= 0.1, it is not worth scaling by C.</pre><p> <pre> AMAX (output) float* Absolute value of largest matrix element. If AMAX is very close to overflow or very close to underflow, the matrix should be scaled.</pre><p> <pre> INFO (output) int* = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value > 0: if INFO = i, and i is <= A->nrow: the i-th row of A is exactly zero > A->ncol: the (i-M)-th column of A is exactly zero</pre><p> <pre> ===================================================================== </pre> </div> </div><p> </div> <hr size="1"><address style="text-align: right;"><small>Generated on Thu Aug 25 13:43:49 2011 for SuperLU by <a href="http://www.doxygen.org/index.html"> <img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.5.5 </small></address> </body> </html>