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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="MatGetMultiProcBlock"><H1>MatGetMultiProcBlock</H1></A>
Create multiple [bjacobi] 'parallel submatrices' from a given 'mat' object. Each submatrix can span multiple procs.
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscmat.h"
PetscErrorCode MatGetMultiProcBlock(Mat mat, MPI_Comm subComm, MatReuse scall,Mat *subMat)
</PRE>
Collective on <A HREF="../Mat/Mat.html#Mat">Mat</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>mat </B></TD><TD>- the matrix
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>subcomm </B></TD><TD>- the subcommunicator obtained by com_split(comm)
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>scall </B></TD><TD>- either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Output Parameter</FONT></H3>
<DT><B>subMat </B> -'parallel submatrices each spans a given subcomm
<br>
<P>
<H3><FONT COLOR="#CC3333">Notes</FONT></H3>
The submatrix partition across processors is dictated by 'subComm' a
communicator obtained by com_split(comm). The comm_split
is not restriced to be grouped with consecutive original ranks.
<P>
Due the comm_split() usage, the parallel layout of the submatrices
map directly to the layout of the original matrix [wrt the local
row,col partitioning]. So the original 'DiagonalMat' naturally maps
into the 'DiagonalMat' of the subMat, hence it is used directly from
the subMat. However the offDiagMat looses some columns - and this is
reconstructed with <A HREF="../Mat/MatSetValues.html#MatSetValues">MatSetValues</A>()
<P>
<P>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../Mat/MatGetSubMatrices.html#MatGetSubMatrices">MatGetSubMatrices</A>()
<BR><P><B><P><B><FONT COLOR="#CC3333">Level:</FONT></B>advanced
<BR><FONT COLOR="#CC3333">Location:</FONT></B><A HREF="../../../src/mat/interface/matrix.c.html#MatGetMultiProcBlock">src/mat/interface/matrix.c</A>
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