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<div id="version" align=right><b>petsc-3.10.3 2018-12-18</b></div>
<div id="bugreport" align=right><a href="mailto:petsc-maint@mcs.anl.gov?subject=Typo or Error in Documentation &body=Please describe the typo or error in the documentation: petsc-3.10.3 v3.10.3 docs/manualpages/KSP/KSPLSQRSetExactMatNorm.html "><small>Report Typos and Errors</small></a></div>
<A NAME="KSPLSQRSetExactMatNorm"><H1>KSPLSQRSetExactMatNorm</H1></A>
Compute exact matrix norm instead of iteratively refined estimate.
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscksp.h"
<A HREF="../Sys/PetscErrorCode.html#PetscErrorCode">PetscErrorCode</A> <A HREF="../KSP/KSPLSQRSetExactMatNorm.html#KSPLSQRSetExactMatNorm">KSPLSQRSetExactMatNorm</A>(<A HREF="../KSP/KSP.html#KSP">KSP</A> ksp, <A HREF="../Sys/PetscBool.html#PetscBool">PetscBool</A> flg)
</PRE>
Not Collective
<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>ksp </B></TD><TD>- iterative context
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>flg </B></TD><TD>- compute exact matrix norm or not
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Notes</FONT></H3>
By default, flg=<A HREF="../Sys/PETSC_FALSE.html#PETSC_FALSE">PETSC_FALSE</A>. This is usually preferred to avoid possibly expensive computation of the norm.
For flg=<A HREF="../Sys/PETSC_TRUE.html#PETSC_TRUE">PETSC_TRUE</A>, we call <A HREF="../Mat/MatNorm.html#MatNorm">MatNorm</A>(Amat,<A HREF="../Vec/NORM_FROBENIUS.html#NORM_FROBENIUS">NORM_FROBENIUS</A>,&lsqr->anorm) which will work only for some types of explicitly assembled matrices.
This can affect convergence rate as <A HREF="../KSP/KSPLSQRConvergedDefault.html#KSPLSQRConvergedDefault">KSPLSQRConvergedDefault</A>() assumes different value of ||A|| used in normal equation stopping criterion.
<P>
<P>
<H3><FONT COLOR="#CC3333">Keywords</FONT></H3>
<A HREF="../KSP/KSP.html#KSP">KSP</A>, <A HREF="../KSP/KSPLSQR.html#KSPLSQR">KSPLSQR</A>
<BR>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../KSP/KSPSolve.html#KSPSolve">KSPSolve</A>(), <A HREF="../KSP/KSPLSQR.html#KSPLSQR">KSPLSQR</A>, <A HREF="../KSP/KSPLSQRGetNorms.html#KSPLSQRGetNorms">KSPLSQRGetNorms</A>(), <A HREF="../KSP/KSPLSQRConvergedDefault.html#KSPLSQRConvergedDefault">KSPLSQRConvergedDefault</A>()
<BR><P><B></B><H3><FONT COLOR="#CC3333">Level</FONT></H3>intermediate<BR>
<H3><FONT COLOR="#CC3333">Location</FONT></H3>
</B><A HREF="../../../src/ksp/ksp/impls/lsqr/lsqr.c.html#KSPLSQRSetExactMatNorm">src/ksp/ksp/impls/lsqr/lsqr.c</A>
<BR><A HREF="./index.html">Index of all KSP routines</A>
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