File: PCFactorSetShiftNonzero.html

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML3.2 EN">
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<TITLE>PCFactorSetShiftNonzero</TITLE>
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<A NAME="PCFactorSetShiftNonzero"><H1>PCFactorSetShiftNonzero</H1></A>
adds this quantity to the diagonal of the matrix during  numerical factorization, thus the matrix has nonzero pivots 
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscpc.h" 
PetscErrorCode PETSCKSP_DLLEXPORT PCFactorSetShiftNonzero(PC pc,PetscReal shift)
</PRE>
Collective on <A HREF="../PC/PC.html#PC">PC</A>
<P>
<H3><FONT COLOR="#CC3333">Input Parameters</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>pc </B></TD><TD>- the preconditioner context
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>shift </B></TD><TD>- amount of shift
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Options Database Key</FONT></H3>
<DT><B>-pc_factor_shift_nonzero &lt;shift&gt; </B> -Sets shift amount or <A HREF="../Sys/PETSC_DECIDE.html#PETSC_DECIDE">PETSC_DECIDE</A> for the default
<br>
<P>
Note: If 0.0 is given, then no shift is used. If a diagonal element is classified as a zero
pivot, then the shift is doubled until this is alleviated.
<P>

<P>
<H3><FONT COLOR="#CC3333">Keywords</FONT></H3>
 <A HREF="../PC/PC.html#PC">PC</A>, set, factorization, direct, fill
<BR>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
 <A HREF="../PC/PCFactorSetZeroPivot.html#PCFactorSetZeroPivot">PCFactorSetZeroPivot</A>(), <A HREF="../PC/PCFactorSetShiftPd.html#PCFactorSetShiftPd">PCFactorSetShiftPd</A>()
<BR><P><B><P><B><FONT COLOR="#CC3333">Level:</FONT></B>intermediate
<BR><FONT COLOR="#CC3333">Location:</FONT></B><A HREF="../../../src/ksp/pc/impls/factor/factor.c.html#PCFactorSetShiftNonzero">src/ksp/pc/impls/factor/factor.c</A>
<BR><A HREF="./index.html">Index of all PC routines</A>
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