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<div id="version" align=right><b>petsc-3.14.5 2021-03-03</b></div>
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<A NAME="MatFactorCreateSchurComplement"><H1>MatFactorCreateSchurComplement</H1></A>
Create a Schur complement matrix object using Schur data computed during the factorization step
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscmat.h"
<A HREF="../Sys/PetscErrorCode.html#PetscErrorCode">PetscErrorCode</A> <A HREF="../Mat/MatFactorCreateSchurComplement.html#MatFactorCreateSchurComplement">MatFactorCreateSchurComplement</A>(<A HREF="../Mat/Mat.html#Mat">Mat</A> F,<A HREF="../Mat/Mat.html#Mat">Mat</A>* S,MatFactorSchurStatus* status)
</PRE>
Logically 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>F </B></TD><TD>- the factored matrix obtained by calling <A HREF="../Mat/MatGetFactor.html#MatGetFactor">MatGetFactor</A>() from PETSc-MUMPS interface
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>S </B></TD><TD>- location where to return the Schur complement, can be NULL
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>status </B></TD><TD>- the status of the Schur complement matrix, can be NULL
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Notes</FONT></H3>
You must call <A HREF="../Mat/MatFactorSetSchurIS.html#MatFactorSetSchurIS">MatFactorSetSchurIS</A>() before calling this routine.
<P>
The routine provides a copy of the Schur matrix stored within the solver data structures.
The caller must destroy the object when it is no longer needed.
If <A HREF="../Mat/MatFactorInvertSchurComplement.html#MatFactorInvertSchurComplement">MatFactorInvertSchurComplement</A>() has been called, the routine gets back the inverse.
<P>
Use <A HREF="../Mat/MatFactorGetSchurComplement.html#MatFactorGetSchurComplement">MatFactorGetSchurComplement</A>() to get access to the Schur complement matrix inside the factored matrix instead of making a copy of it (which this function does)
<P>
<H3><FONT COLOR="#CC3333">Developer Notes</FONT></H3>
The reason this routine exists is because the representation of the Schur complement within the factor matrix may be different than a standard PETSc
matrix representation and we normally do not want to use the time or memory to make a copy as a regular PETSc matrix.
<P>
See <A HREF="../KSP/MatCreateSchurComplement.html#MatCreateSchurComplement">MatCreateSchurComplement</A>() or <A HREF="../KSP/MatGetSchurComplement.html#MatGetSchurComplement">MatGetSchurComplement</A>() for ways to create virtual or approximate Schur complements.
<P>
<P>
<H3><FONT COLOR="#CC3333">References</FONT></H3>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../Mat/MatGetFactor.html#MatGetFactor">MatGetFactor</A>(), <A HREF="../Mat/MatFactorSetSchurIS.html#MatFactorSetSchurIS">MatFactorSetSchurIS</A>(), <A HREF="../Mat/MatFactorGetSchurComplement.html#MatFactorGetSchurComplement">MatFactorGetSchurComplement</A>(), MatFactorSchurStatus
<BR><P><B></B><H3><FONT COLOR="#CC3333">Level</FONT></H3>advanced<BR>
<H3><FONT COLOR="#CC3333">Location</FONT></H3>
</B><A HREF="../../../src/mat/interface/matrix.c.html#MatFactorCreateSchurComplement">src/mat/interface/matrix.c</A>
<P><H3><FONT COLOR="CC3333">Implementations</FONT></H3><A HREF="../../../src/mat/impls/aij/mpi/mumps/mumps.c.html#MatFactorCreateSchurComplement_MUMPS">MatFactorCreateSchurComplement_MUMPS in src/mat/impls/aij/mpi/mumps/mumps.c</A><BR>
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