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mld2p4:

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Further doc fixes.
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Salvatore Filippone
2008-07-24 06:05:46 +00:00
parent 4dda0494a7
commit 78805bf653
130 changed files with 10569 additions and 7036 deletions
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<H1><A NAME="SECTION00070000000000000000"></A><A NAME="sec:started"></A>
@@ -68,16 +67,16 @@ Schwarz preconditioners with the Krylov solvers included in PSBLAS [<A
The following steps are required:
<OL>
<LI><SPAN CLASS="textit">Declare the preconditioner data structure</SPAN>. It is a derived data type,
<code>mld_</code><SPAN CLASS="textit">x</SPAN><code>prec_</code> <code>type</code>, where <SPAN CLASS="textit">x</SPAN> may be <code>s</code>, <code>d</code>, <code>c</code>
<LI><I>Declare the preconditioner data structure</I>. It is a derived data type,
<code>mld_</code><I>x</I><code>prec_</code> <code>type</code>, where <I>x</I> may be <code>s</code>, <code>d</code>, <code>c</code>
or <code>z</code>, according to the basic data type of the sparse matrix
(<code>s</code> = real single precision; <code>d</code> = real double precision;
<code>c</code> = complex single precision; <code>z</code> = complex double precision).
This data structure is accessed by the user only through the MLD2P4 routines,
following an object-oriented approach.
</LI>
<LI><SPAN CLASS="textit">Allocate and initialize the preconditioner data structure, according to
a preconditioner type chosen by the user</SPAN>. This is performed by the routine
<LI><I>Allocate and initialize the preconditioner data structure, according to
a preconditioner type chosen by the user</I>. This is performed by the routine
<code>mld_precinit</code>, which also sets defaults for each preconditioner
type selected by the user. The defaults associated to each preconditioner
type are given in Table&nbsp;<A HREF="#tab:precinit">1</A>, where the strings used by
@@ -85,8 +84,8 @@ The following steps are required:
Note that these strings are valid also if uppercase letters are substituted by
corresponding lowercase ones.
</LI>
<LI><SPAN CLASS="textit">Modify the selected preconditioner type, by properly setting
preconditioner parameters.</SPAN> This is performed by the routine <code>mld_precset</code>.
<LI><I>Modify the selected preconditioner type, by properly setting
preconditioner parameters.</I> This is performed by the routine <code>mld_precset</code>.
This routine must be called only if the user wants to modify the default values
of the parameters associated to the selected preconditioner type, to obtain a variant
of the preconditioner. Examples of use of <code>mld_precset</code> are given in
@@ -94,15 +93,15 @@ The following steps are required:
preconditioner parameters and their allowed and default values is provided in
Section&nbsp;<A HREF="node15.html#sec:userinterface">6</A>, Tables&nbsp;<A HREF="#tab:p_type">2</A>-<A HREF="#tab:p_coarse">5</A>.
</LI>
<LI><SPAN CLASS="textit">Build the preconditioner for a given matrix.</SPAN> This is performed by
<LI><I>Build the preconditioner for a given matrix.</I> This is performed by
the routine <code>mld_precbld</code>.
</LI>
<LI><SPAN CLASS="textit">Apply the preconditioner at each iteration of a Krylov solver.</SPAN>
<LI><I>Apply the preconditioner at each iteration of a Krylov solver.</I>
This is performed by the routine <code>mld_precaply</code>. When using the PSBLAS Krylov solvers,
this step is completely transparent to the user, since <code>mld_precaply</code> is called
by the PSBLAS routine implementing the Krylov solver (<code>psb_krylov</code>).
</LI>
<LI><SPAN CLASS="textit">Free the preconditioner data structure</SPAN>. This is performed by
<LI><I>Free the preconditioner data structure</I>. This is performed by
the routine <code>mld_</code> <code>precfree</code>. This step is complementary to step 1 and should
be performed when the preconditioner is no more used.
</LI>
@@ -120,7 +119,7 @@ Krylov solvers, must be also used (see Section&nbsp;<A HREF="node14.html#sec:exa
<P>
<BR><SPAN CLASS="textbf">Remark 1.</SPAN> The coarsest-level solver used by the default two-level
<BR><B>Remark 1.</B> The coarsest-level solver used by the default two-level
preconditioner has been chosen by taking into account that, on parallel
machines, it often leads to the smallest execution time when applied to
linear systems coming from finite-difference discretizations of basic
@@ -136,7 +135,7 @@ for the coarsest-level solvers available in MLD2P4).
<P>
<BR><SPAN CLASS="textbf">Remark 2.</SPAN> The include path for MLD2P4 must override
<BR><B>Remark 2.</B> The include path for MLD2P4 must override
those for PSBLAS, e.g. the latter must come first in the sequence
passed to the compiler, as the MLD2P4 version of the Krylov solver
interfaces must override that of PSBLAS. This will change in the future
@@ -155,46 +154,46 @@ Preconditioner types, corresponding strings and default choices.
<TABLE CELLPADDING=3 BORDER="1" ALIGN="CENTER">
<TR><TD ALIGN="LEFT"><SMALL>TYPE</SMALL></TD>
<TD ALIGN="LEFT"><SMALL>STRING</SMALL></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=181><SMALL>DEFAULT PRECONDITIONER</SMALL></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=221><SMALL>DEFAULT PRECONDITIONER</SMALL></TD>
</TR>
<TR><TD ALIGN="LEFT">No preconditioner</TD>
<TD ALIGN="LEFT"><code>'NOPREC'</code></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=181>Considered only to use the PSBLAS
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=221>Considered only to use the PSBLAS
Krylov solvers with no preconditioner.</TD>
</TR>
<TR><TD ALIGN="LEFT">Diagonal</TD>
<TD ALIGN="LEFT"><code>'DIAG'</code></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=181>--</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=221>--</TD>
</TR>
<TR><TD ALIGN="LEFT">Block Jacobi</TD>
<TD ALIGN="LEFT"><code>'BJAC'</code></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=181>Block Jacobi with ILU(0) on the local blocks.</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=221>Block Jacobi with ILU(0) on the local blocks.</TD>
</TR>
<TR><TD ALIGN="LEFT">Additive Schwarz</TD>
<TD ALIGN="LEFT"><code>'AS'</code></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=181>Restricted Additive Schwarz (RAS),
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=221>Restricted Additive Schwarz (RAS),
with overlap 1 and ILU(0) on the local blocks.</TD>
</TR>
<TR><TD ALIGN="LEFT">Multilevel</TD>
<TD ALIGN="LEFT"><code>'ML'</code></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=181>Multi-level hybrid preconditioner (additive on the
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=221>Multi-level hybrid preconditioner (additive on the
same level and multiplicative through the levels),
with post-smoothing only.
Number of levels: 2.
Post-smoother: RAS with overlap 1 and ILU(0)
on the local blocks.
Aggregation: smoothed aggregation with
threshold <SPAN CLASS="MATH"><IMG
Aggregation: decoupled smoothed aggregation with
threshold <IMG
WIDTH="45" HEIGHT="15" ALIGN="BOTTOM" BORDER="0"
SRC="img86.png"
ALT="$\theta = 0$"></SPAN>.
ALT="$\theta = 0$">.
Coarsest matrix: distributed among the processors.
Coarsest-level solver:
4 sweeps of the block-Jacobi solver,
with LU (or ILU) factorization of the blocks
(UMFPACK for the double precision versions and
SuperLU for the single precision ones, if they have been
installed; ILU(0), otherwise).</TD>
SuperLU for the single precision ones, if the packages
have been installed; ILU(0), otherwise).</TD>
</TR>
</TABLE>
</DIV>
@@ -210,13 +209,12 @@ Preconditioner types, corresponding strings and default choices.
<!--Table of Child-Links-->
<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></A>
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<UL>
<LI><A NAME="tex2html218"
HREF="node14.html">Examples</A>
</UL>
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@@ -242,11 +240,11 @@ Preconditioner types, corresponding strings and default choices.
<B> Previous:</B> <A NAME="tex2html207"
HREF="node12.html">Smoothed Aggregation</A>
&nbsp; <B> <A NAME="tex2html215"
HREF="node2.html">Contents</A></B> </DIV>
HREF="node2.html">Contents</A></B>
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<ADDRESS>
Salvatore Filippone
2008-07-23
2008-07-24
</ADDRESS>
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