<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <!--Converted with LaTeX2HTML 2002-2-1 (1.71) original version by: Nikos Drakos, CBLU, University of Leeds * revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan * with significant contributions from: Jens Lippmann, Marek Rouchal, Martin Wilck and others --> <HTML> <HEAD> <TITLE>Subroutine mld_precaply</TITLE> <META NAME="description" CONTENT="Subroutine mld_precaply"> <META NAME="keywords" CONTENT="userhtml"> <META NAME="resource-type" CONTENT="document"> <META NAME="distribution" CONTENT="global"> <META NAME="Generator" CONTENT="LaTeX2HTML v2002-2-1"> <META HTTP-EQUIV="Content-Style-Type" CONTENT="text/css"> <LINK REL="STYLESHEET" HREF="userhtml.css"> <LINK REL="next" HREF="node21.html"> <LINK REL="previous" HREF="node19.html"> <LINK REL="up" HREF="node16.html"> <LINK REL="next" HREF="node21.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html308" HREF="node21.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="file:/usr/share/latex2html/icons/next.png"></A> <A NAME="tex2html304" HREF="node16.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="file:/usr/share/latex2html/icons/up.png"></A> <A NAME="tex2html298" HREF="node19.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="file:/usr/share/latex2html/icons/prev.png"></A> <A NAME="tex2html306" HREF="node2.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="file:/usr/share/latex2html/icons/contents.png"></A> <BR> <B> Next:</B> <A NAME="tex2html309" HREF="node21.html">Subroutine mld_precfree</A> <B> Up:</B> <A NAME="tex2html305" HREF="node16.html">User Interface</A> <B> Previous:</B> <A NAME="tex2html299" HREF="node19.html">Subroutine mld_precbld</A> <B> <A NAME="tex2html307" HREF="node2.html">Contents</A></B> <BR> <BR> <!--End of Navigation Panel--> <H2><A NAME="SECTION00084000000000000000"></A><A NAME="sec:precaply"></A> <BR> Subroutine mld_precaply </H2> <P> <DIV ALIGN="CENTER"> <code>mld_precaply(p,x,y,desc_a,info)</code> <BR><code>mld_precaply(p,x,y,desc_a,info,trans,work)</code> <BR> </DIV> <P> This routine computes <!-- MATH $y = op(M^{-1})\, x$ --> <IMG WIDTH="117" HEIGHT="39" ALIGN="MIDDLE" BORDER="0" SRC="img96.png" ALT="$y = op(M^{-1}) x$">, where <IMG WIDTH="23" HEIGHT="15" ALIGN="BOTTOM" BORDER="0" SRC="img59.png" ALT="$M$"> is a previously built preconditioner, stored into <code>p</code>, and <IMG WIDTH="22" HEIGHT="31" ALIGN="MIDDLE" BORDER="0" SRC="img97.png" ALT="$op$"> denotes the preconditioner itself or its transpose, according to the value of <code>trans</code>. Note that, when MLD2P4 is used with a Krylov solver from PSBLAS, <code>mld_precaply</code> is called within the PSBLAS routine <code>psb_krylov</code> and hence it is completely transparent to the user. <P> <FONT SIZE="+1"><B>Arguments</B></FONT> <P> <TABLE CELLPADDING=3> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34><code>p</code></TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><code>type(mld_</code><I>x</I><code>prec_type), intent(inout)</code>.</TD> </TR> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34> </TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>The preconditioner data structure, containing the local part of <IMG WIDTH="23" HEIGHT="15" ALIGN="BOTTOM" BORDER="0" SRC="img59.png" ALT="$M$">. Note that <I>x</I> must be chosen according to the real/complex, single/double precision version of MLD2P4 under use.</TD> </TR> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34><code>x</code></TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><I>type</I><code>(</code><I>kind_parameter</I><code>), dimension(:), intent(in)</code>.</TD> </TR> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34> </TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>The local part of the vector <IMG WIDTH="14" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" SRC="img98.png" ALT="$x$">. Note that <I>type</I> and <I>kind_parameter</I> must be chosen according to the real/complex, single/double precision version of MLD2P4 under use.</TD> </TR> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34><code>y</code></TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><I>type</I><code>(</code><I>kind_parameter</I><code>), dimension(:), intent(out)</code>.</TD> </TR> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34> </TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>The local part of the vector <IMG WIDTH="14" HEIGHT="31" ALIGN="MIDDLE" BORDER="0" SRC="img99.png" ALT="$y$">. Note that <I>type</I> and <I>kind_parameter</I> must be chosen according to the real/complex, single/double precision version of MLD2P4 under use.</TD> </TR> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34><code>desc_a</code></TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><code>type(psb_desc_type), intent(in)</code>.</TD> </TR> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34> </TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>The communication descriptor associated to the matrix to be preconditioned.</TD> </TR> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34><code>info</code></TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><code>integer, intent(out)</code>.</TD> </TR> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34> </TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>Error code. If no error, 0 is returned. See Section <A HREF="node23.html#sec:errors">7</A> for details.</TD> </TR> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34><code>trans</code></TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><code>character(len=1), optional, intent(in).</code></TD> </TR> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34> </TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>If <code>trans</code> = <code>'N','n'</code> then <!-- MATH $op(M^{-1}) = M^{-1}$ --> <IMG WIDTH="132" HEIGHT="39" ALIGN="MIDDLE" BORDER="0" SRC="img100.png" ALT="$op(M^{-1}) = M^{-1}$">; if <code>trans</code> = <code>'T','t'</code> then <!-- MATH $op(M^{-1}) = M^{-T}$ --> <IMG WIDTH="135" HEIGHT="40" ALIGN="MIDDLE" BORDER="0" SRC="img101.png" ALT="$op(M^{-1}) = M^{-T}$"> (transpose of <IMG WIDTH="48" HEIGHT="39" ALIGN="MIDDLE" BORDER="0" SRC="img102.png" ALT="$M^{-1})$">; if <code>trans</code> = <code>'C','c'</code> then <!-- MATH $op(M^{-1}) = M^{-C}$ --> <IMG WIDTH="136" HEIGHT="40" ALIGN="MIDDLE" BORDER="0" SRC="img103.png" ALT="$op(M^{-1}) = M^{-C}$"> (conjugate transpose of <IMG WIDTH="48" HEIGHT="39" ALIGN="MIDDLE" BORDER="0" SRC="img102.png" ALT="$M^{-1})$">.</TD> </TR> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34><code>work</code></TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><I>type</I><code>(</code><I>kind_parameter</I><code>), dimension(:), optional, target</code>.</TD> </TR> <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34> </TD> <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>Workspace. Its size should be at least <code>4 * psb_cd_get_local_</code> <code>cols(desc_a)</code> (see the PSBLAS User's Guide). Note that <I>type</I> and <I>kind_parameter</I> must be chosen according to the real/complex, single/double precision version of MLD2P4 under use.</TD> </TR> </TABLE> <P> <P> <HR> <!--Navigation Panel--> <A NAME="tex2html308" HREF="node21.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="file:/usr/share/latex2html/icons/next.png"></A> <A NAME="tex2html304" HREF="node16.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="file:/usr/share/latex2html/icons/up.png"></A> <A NAME="tex2html298" HREF="node19.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="file:/usr/share/latex2html/icons/prev.png"></A> <A NAME="tex2html306" HREF="node2.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="file:/usr/share/latex2html/icons/contents.png"></A> <BR> <B> Next:</B> <A NAME="tex2html309" HREF="node21.html">Subroutine mld_precfree</A> <B> Up:</B> <A NAME="tex2html305" HREF="node16.html">User Interface</A> <B> Previous:</B> <A NAME="tex2html299" HREF="node19.html">Subroutine mld_precbld</A> <B> <A NAME="tex2html307" HREF="node2.html">Contents</A></B> <!--End of Navigation Panel--> </BODY> </HTML>