1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML3.2 EN">
<HTML>
<HEAD> <link rel="canonical" href="http://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/KSP/MatCreateSchurComplementPmat.html" />
<META NAME="GENERATOR" CONTENT="DOCTEXT">
<TITLE>MatCreateSchurComplementPmat</TITLE>
</HEAD>
<BODY BGCOLOR="FFFFFF">
<div id="version" align=right><b>petsc-3.14.5 2021-03-03</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-3.14.5 v3.14.5 docs/manualpages/KSP/MatCreateSchurComplementPmat.html "><small>Report Typos and Errors</small></a></div>
<A NAME="MatCreateSchurComplementPmat"><H1>MatCreateSchurComplementPmat</H1></A>
create a preconditioning matrix for the Schur complement by assembling Sp = A11 - A10 inv(diag(A00)) A01
<H3><FONT COLOR="#CC3333">Synopsis</FONT></H3>
<PRE>
#include "petscksp.h"
<A HREF="../Sys/PetscErrorCode.html#PetscErrorCode">PetscErrorCode</A> <A HREF="../KSP/MatCreateSchurComplementPmat.html#MatCreateSchurComplementPmat">MatCreateSchurComplementPmat</A>(<A HREF="../Mat/Mat.html#Mat">Mat</A> A00,<A HREF="../Mat/Mat.html#Mat">Mat</A> A01,<A HREF="../Mat/Mat.html#Mat">Mat</A> A10,<A HREF="../Mat/Mat.html#Mat">Mat</A> A11,<A HREF="../KSP/MatSchurComplementAinvType.html#MatSchurComplementAinvType">MatSchurComplementAinvType</A> ainvtype,<A HREF="../Mat/MatReuse.html#MatReuse">MatReuse</A> preuse,<A HREF="../Mat/Mat.html#Mat">Mat</A> *Spmat)
</PRE>
Collective on A00
<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>A00,A01,A10,A11 </B></TD><TD>- the four parts of the original matrix A = [A00 A01; A10 A11] (A01,A10, and A11 are optional, implying zero matrices)
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>ainvtype </B></TD><TD>- type of approximation for inv(A00) used when forming Sp = A11 - A10 inv(A00) A01
</TD></TR>
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>preuse </B></TD><TD>- <A HREF="../Mat/MatReuse.html#MatReuse">MAT_INITIAL_MATRIX</A> for a new Sp, or <A HREF="../Mat/MatReuse.html#MatReuse">MAT_REUSE_MATRIX</A> to reuse an existing Sp, or <A HREF="../Mat/MatReuse.html#MatReuse">MAT_IGNORE_MATRIX</A> to put nothing in Sp
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Output Parameter</FONT></H3>
<TABLE border="0" cellpadding="0" cellspacing="0">
<TR><TD WIDTH=40></TD><TD ALIGN=LEFT VALIGN=TOP><B>Spmat </B></TD><TD>- approximate Schur complement suitable for preconditioning S = A11 - A10 inv(diag(A00)) A01
</TD></TR></TABLE>
<P>
<H3><FONT COLOR="#CC3333">Note</FONT></H3>
Since the real Schur complement is usually dense, providing a good approximation to newpmat usually requires
application-specific information. The default for assembled matrices is to use the inverse of the diagonal of
the (0,0) block A00 in place of A00^{-1}. This rarely produce a scalable algorithm. Optionally, A00 can be lumped
before forming inv(diag(A00)).
<P>
<P>
<H3><FONT COLOR="#CC3333">See Also</FONT></H3>
<A HREF="../KSP/MatCreateSchurComplement.html#MatCreateSchurComplement">MatCreateSchurComplement</A>(), <A HREF="../KSP/MatGetSchurComplement.html#MatGetSchurComplement">MatGetSchurComplement</A>(), <A HREF="../KSP/MatSchurComplementGetPmat.html#MatSchurComplementGetPmat">MatSchurComplementGetPmat</A>(), <A HREF="../KSP/MatSchurComplementAinvType.html#MatSchurComplementAinvType">MatSchurComplementAinvType</A>
<BR><P><B></B><H3><FONT COLOR="#CC3333">Level</FONT></H3>advanced<BR>
<H3><FONT COLOR="#CC3333">Location</FONT></H3>
</B><A HREF="../../../src/ksp/ksp/utils/schurm/schurm.c.html#MatCreateSchurComplementPmat">src/ksp/ksp/utils/schurm/schurm.c</A>
<BR><A HREF="./index.html">Index of all KSP 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>
</BODY></HTML>
|
