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<div id="version" align=right><b>petsc-3.7.5 2017-01-01</b></div>
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<A NAME="MatGetLocalSubMatrix"><H1>MatGetLocalSubMatrix</H1></A>
Gets a reference to a submatrix specified in local numbering
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscmat.h"
PetscErrorCode MatGetLocalSubMatrix(Mat mat,IS isrow,IS iscol,Mat *submat)
</PRE>
Not Collective
<P>
<H3><FONT COLOR="#CC3333">Input Arguments</FONT></H3>
mat - matrix to extract local submatrix from
isrow - local row indices for submatrix
iscol - local column indices for submatrix
<P>
<H3><FONT COLOR="#CC3333">Output Arguments</FONT></H3>
submat - the submatrix
<P>
<P>
<H3><FONT COLOR="#CC3333">Notes</FONT></H3>
The submat should be returned with <A HREF="../Mat/MatRestoreLocalSubMatrix.html#MatRestoreLocalSubMatrix">MatRestoreLocalSubMatrix</A>().
<P>
Depending on the format of mat, the returned submat may not implement <A HREF="../Mat/MatMult.html#MatMult">MatMult</A>(). Its communicator may be
the same as mat, it may be <A HREF="../Sys/PETSC_COMM_SELF.html#PETSC_COMM_SELF">PETSC_COMM_SELF</A>, or some other subcomm of mat's.
<P>
The submat always implements <A HREF="../Mat/MatSetValuesLocal.html#MatSetValuesLocal">MatSetValuesLocal</A>(). If isrow and iscol have the same block size, then
<A HREF="../Mat/MatSetValuesBlockedLocal.html#MatSetValuesBlockedLocal">MatSetValuesBlockedLocal</A>() will also be implemented.
<P>
The mat must have had a <A HREF="../IS/ISLocalToGlobalMapping.html#ISLocalToGlobalMapping">ISLocalToGlobalMapping</A> provided to it with <A HREF="../Mat/MatSetLocalToGlobalMapping.html#MatSetLocalToGlobalMapping">MatSetLocalToGlobalMapping</A>(). Note that
matrices obtained with DMCreateMat() generally already have the local to global mapping provided.
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../Mat/MatRestoreLocalSubMatrix.html#MatRestoreLocalSubMatrix">MatRestoreLocalSubMatrix</A>(), <A HREF="../Mat/MatCreateLocalRef.html#MatCreateLocalRef">MatCreateLocalRef</A>(), <A HREF="../Mat/MatSetLocalToGlobalMapping.html#MatSetLocalToGlobalMapping">MatSetLocalToGlobalMapping</A>()
<BR><P><B><P><B><FONT COLOR="#CC3333">Level:</FONT></B>intermediate
<BR><FONT COLOR="#CC3333">Location:</FONT></B><A HREF="../../../src/mat/interface/matrix.c.html#MatGetLocalSubMatrix">src/mat/interface/matrix.c</A>
<BR><A HREF="./index.html">Index of all Mat routines</A>
<BR><A HREF="../../index.html">Table of Contents for all manual pages</A>
<BR><A HREF="../singleindex.html">Index of all manual pages</A>
<P><H3><FONT COLOR="#CC3333">Examples</FONT></H3>
<A HREF="../../../src/snes/examples/tutorials/ex28.c.html">src/snes/examples/tutorials/ex28.c.html</A><BR>
<A HREF="../../../src/ts/examples/tutorials/ex14.c.html">src/ts/examples/tutorials/ex14.c.html</A><BR>
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