<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"> <!--Converted with LaTeX2HTML 2012 (1.2) 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>psb_cdall -- Allocates a communication descriptor</TITLE> <META NAME="description" CONTENT="psb_cdall -- Allocates a communication descriptor"> <META NAME="keywords" CONTENT="userhtml"> <META NAME="resource-type" CONTENT="document"> <META NAME="distribution" CONTENT="global"> <META NAME="Generator" CONTENT="LaTeX2HTML v2012"> <META HTTP-EQUIV="Content-Style-Type" CONTENT="text/css"> <LINK REL="STYLESHEET" HREF="userhtml.css"> <LINK REL="next" HREF="node70.html"> <LINK REL="previous" HREF="node68.html"> <LINK REL="up" HREF="node68.html"> <LINK REL="next" HREF="node70.html"> </HEAD> <BODY > <!--Navigation Panel--> <A NAME="tex2html1118" HREF="node70.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html1114" HREF="node68.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html1108" HREF="node68.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <A NAME="tex2html1116" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> <BR> <B> Next:</B> <A NAME="tex2html1119" HREF="node70.html">psb_cdins Communication</A> <B> Up:</B> <A NAME="tex2html1115" HREF="node68.html">Data management routines</A> <B> Previous:</B> <A NAME="tex2html1109" HREF="node68.html">Data management routines</A> <B> <A NAME="tex2html1117" HREF="node1.html">Contents</A></B> <BR> <BR> <!--End of Navigation Panel--> <H2><A NAME="SECTION00071000000000000000"> psb_cdall -- Allocates a communication descriptor</A> </H2> <P> <PRE> call psb_cdall(icontxt, desc_a, info,mg=mg,parts=parts) call psb_cdall(icontxt, desc_a, info,vg=vg,[mg=mg,flag=flag]) call psb_cdall(icontxt, desc_a, info,vl=vl,[nl=nl,globalcheck=.true.,lidx=lidx]) call psb_cdall(icontxt, desc_a, info,nl=nl) call psb_cdall(icontxt, desc_a, info,mg=mg,repl=.true.) </PRE> <P> This subroutine initializes the communication descriptor associated with an index space. One of the optional arguments <code>parts</code>, <code>vg</code>, <code>vl</code>, <code>nl</code> or <code>repl</code> must be specified, thereby choosing the specific initialization strategy. <DL> <DT><STRONG><B>On Entry </B></STRONG></DT> <DD> </DD> <DT><STRONG>Type:</STRONG></DT> <DD>Synchronous. </DD> <DT><STRONG>icontxt</STRONG></DT> <DD>the communication context. <BR> Scope:<B>global</B>. <BR> Type:<B>required</B>. <BR> Intent: <B>in</B>. <BR> Specified as: an integer value. </DD> <DT><STRONG>vg</STRONG></DT> <DD>Data allocation: each index <!-- MATH $i\in \{1\dots mg\}$ --> <IMG WIDTH="98" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" SRC="img82.png" ALT="$i\in \{1\dots mg\}$"> is allocated to process <IMG WIDTH="39" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" SRC="img83.png" ALT="$vg(i)$">. <BR> Scope:<B>global</B>. <BR> Type:<B>optional</B>. <BR> Intent: <B>in</B>. <BR> Specified as: an integer array. </DD> <DT><STRONG>flag</STRONG></DT> <DD>Specifies whether entries in <IMG WIDTH="20" HEIGHT="30" ALIGN="MIDDLE" BORDER="0" SRC="img84.png" ALT="$vg$"> are zero- or one-based. <BR> Scope:<B>global</B>. <BR> Type:<B>optional</B>. <BR> Intent: <B>in</B>. <BR> Specified as: an integer value <IMG WIDTH="27" HEIGHT="30" ALIGN="MIDDLE" BORDER="0" SRC="img85.png" ALT="$0,1$">, default <IMG WIDTH="12" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" SRC="img86.png" ALT="$0$">. <P> </DD> <DT><STRONG>mg</STRONG></DT> <DD>the (global) number of rows of the problem. <BR> Scope:<B>global</B>. <BR> Type:<B>optional</B>. <BR> Intent: <B>in</B>. <BR> Specified as: an integer value. It is required if <code>parts</code> or <code>repl</code> is specified, it is optional if <code>vg</code> is specified. </DD> <DT><STRONG>parts</STRONG></DT> <DD>the subroutine that defines the partitioning scheme. <BR> Scope:<B>global</B>. <BR> Type:<B>required</B>. <BR> Specified as: a subroutine. </DD> <DT><STRONG>vl</STRONG></DT> <DD>Data allocation: the set of global indices <IMG WIDTH="66" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" SRC="img87.png" ALT="$vl(1:nl)$"> belonging to the calling process. <BR> Scope:<B>local</B>. <BR> Type:<B>optional</B>. <BR> Intent: <B>in</B>. <BR> Specified as: an integer array. </DD> <DT><STRONG>nl</STRONG></DT> <DD>Data allocation: in a generalized block-row distribution the number of indices belonging to the current process. <BR> Scope:<B>local</B>. <BR> Type:<B>optional</B>. <BR> Intent: <B>in</B>. <BR> Specified as: an integer value. May be specified together with <code>vl</code>. </DD> <DT><STRONG>repl</STRONG></DT> <DD>Data allocation: build a replicated index space (i.e. all processes own all indices). <BR> Scope:<B>global</B>. <BR> Type:<B>optional</B>. <BR> Intent: <B>in</B>. <BR> Specified as: the logical value <code>.true.</code> </DD> <DT><STRONG>globalcheck</STRONG></DT> <DD>Data allocation: do global checks on the local index lists <code>vl</code> <BR> Scope:<B>global</B>. <BR> Type:<B>optional</B>. <BR> Intent: <B>in</B>. <BR> Specified as: a logical value, default: <code>.true.</code> </DD> <DT><STRONG>lidx</STRONG></DT> <DD>Data allocation: the set of local indices <IMG WIDTH="80" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" SRC="img88.png" ALT="$lidx(1:nl)$"> to be assigned to the global indices <IMG WIDTH="18" HEIGHT="15" ALIGN="BOTTOM" BORDER="0" SRC="img89.png" ALT="$vl$">. <BR> Scope:<B>local</B>. <BR> Type:<B>optional</B>. <BR> Intent: <B>in</B>. <BR> Specified as: an integer array. </DD> </DL> <P> <DL> <DT><STRONG><B>On Return</B></STRONG></DT> <DD> </DD> <DT><STRONG>desc_a</STRONG></DT> <DD>the communication descriptor. <BR> Scope:<B>local</B>. <BR> Type:<B>required</B>. <BR> Intent: <B>out</B>. <BR> Specified as: a structured data of type descdata<TT>psb_desc_type</TT>. </DD> <DT><STRONG>info</STRONG></DT> <DD>Error code. <BR> Scope: <B>local</B> <BR> Type: <B>required</B> <BR> Intent: <B>out</B>. <BR> An integer value; 0 means no error has been detected. </DD> </DL> <P> <FONT SIZE="+1"><B>Notes</B></FONT> <OL> <LI>One of the optional arguments <code>parts</code>, <code>vg</code>, <code>vl</code>, <code>nl</code> or <code>repl</code> must be specified, thereby choosing the initialization strategy as follows: <DL> <DT><STRONG>parts</STRONG></DT> <DD>In this case we have a subroutine specifying the mapping between global indices and process/local index pairs. If this optional argument is specified, then it is mandatory to specify the argument <code>mg</code> as well. The subroutine must conform to the following interface: <PRE> interface subroutine psb_parts(glob_index,mg,np,pv,nv) integer, intent (in) :: glob_index,np,mg integer, intent (out) :: nv, pv(*) end subroutine psb_parts end interface </PRE> The input arguments are: <DL> <DT><STRONG>glob_index</STRONG></DT> <DD>The global index to be mapped; </DD> <DT><STRONG>np</STRONG></DT> <DD>The number of processes in the mapping; </DD> <DT><STRONG>mg</STRONG></DT> <DD>The total number of global rows in the mapping; </DD> </DL> The output arguments are: <DL> <DT><STRONG>nv</STRONG></DT> <DD>The number of entries in <code>pv</code>; </DD> <DT><STRONG>pv</STRONG></DT> <DD>A vector containing the indices of the processes to which the global index should be assigend; each entry must satisfy <!-- MATH $0\le pv(i) < np$ --> <IMG WIDTH="106" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" SRC="img90.png" ALT="$0\le pv(i) < np$">; if <IMG WIDTH="51" HEIGHT="30" ALIGN="MIDDLE" BORDER="0" SRC="img91.png" ALT="$nv>1$"> we have an index assigned to multiple processes, i.e. we have an overlap among the subdomains. </DD> </DL> </DD> <DT><STRONG>vg</STRONG></DT> <DD>In this case the association between an index and a process is specified via an integer vector <code>vg(1:mg)</code>; each index <!-- MATH $i \in \{1\dots mg\}$ --> <IMG WIDTH="98" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" SRC="img82.png" ALT="$i\in \{1\dots mg\}$"> is assigned to process <IMG WIDTH="39" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" SRC="img83.png" ALT="$vg(i)$">. The vector <code>vg</code> must be identical on all calling processes; its entries may have the ranges <IMG WIDTH="93" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" SRC="img92.png" ALT="$(0\dots np-1)$"> or <IMG WIDTH="66" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" SRC="img93.png" ALT="$(1\dots np)$"> according to the value of <code>flag</code>. The size <IMG WIDTH="26" HEIGHT="30" ALIGN="MIDDLE" BORDER="0" SRC="img94.png" ALT="$mg$"> may be specified via the optional argument <code>mg</code>; the default is to use the entire vector <code>vg</code>, thus having <code>mg=size(vg)</code>. </DD> <DT><STRONG>vl</STRONG></DT> <DD>In this case we are specifying the list of indices <code>vl(1:nl)</code> assigned to the current process; thus, the global problem size <IMG WIDTH="26" HEIGHT="30" ALIGN="MIDDLE" BORDER="0" SRC="img94.png" ALT="$mg$"> is given by the range of the aggregate of the individual vectors <code>vl</code> specified in the calling processes. The size may be specified via the optional argument <code>nl</code>; the default is to use the entire vector <code>vl</code>, thus having <code>nl=size(vl)</code>. If <code>globalcheck=.true.</code> the subroutine will check how many times each entry in the global index space <IMG WIDTH="71" HEIGHT="32" ALIGN="MIDDLE" BORDER="0" SRC="img95.png" ALT="$(1\dots mg)$"> is specified in the input lists <code>vl</code>, thus allowing for the presence of overlap in the input, and checking for ``orphan'' indices. If <code>globalcheck=.false.</code>, the subroutine will not check for overlap, and may be significantly faster, but the user is implicitly guaranteeing that there are neither orphan nor overlap indices. </DD> <DT><STRONG>lidx</STRONG></DT> <DD>The optional argument <code>lidx</code> is available for those cases in which the user has already established a global-to-local mapping; if it is specified, each index in <code>vl(i)</code> will be mapped to the corresponding local index <code>lidx(i)</code>. When specifying the argument <code>lidx</code> the user would also likely employ <code>lidx</code> in calls to <code>psb_cdins</code> and <code>local</code> in calls to <code>psb_spins</code> and <code>psb_geins</code>; see also sec. <A HREF="node7.html#sec:usermaps">2.3.1</A>. </DD> <DT><STRONG>nl</STRONG></DT> <DD>If this argument is specified alone (i.e. without <code>vl</code>) the result is a generalized row-block distribution in which each process <IMG WIDTH="12" HEIGHT="14" ALIGN="BOTTOM" BORDER="0" SRC="img96.png" ALT="$I$"> gets assigned a consecutive chunk of <IMG WIDTH="60" HEIGHT="30" ALIGN="MIDDLE" BORDER="0" SRC="img97.png" ALT="$N_I=nl$"> global indices. </DD> <DT><STRONG>repl</STRONG></DT> <DD>This arguments specifies to replicate all indices on all processes. This is a special purpose data allocation that is useful in the construction of some multilevel preconditioners. </DD> </DL> </LI> <LI>On exit from this routine the descriptor is in the build state. </LI> <LI>Calling the routine with <code>vg</code> or <code>parts</code> implies that every process will scan the entire index space to figure out the local indices. </LI> <LI>Overlapped indices are possible with both <code>parts</code> and <code>vl</code> invocations. </LI> <LI>When the subroutine is invoked with <code>vl</code> in conjunction with <code>globalcheck=.true.</code>, it will perform a scan of the index space to search for overlap or orphan indices. </LI> <LI>When the subroutine is invoked with <code>vl</code> in conjunction with <code>globalcheck=.false.</code>, no index space scan will take place. Thus it is the responsibility of the user to make sure that the indices specified in <code>vl</code> have neither orphans nor overlaps; if this assumption fails, results will be unpredictable. </LI> <LI>Orphan and overlap indices are impossible by construction when the subroutine is invoked with <code>nl</code> (alone), or <code>vg</code>. </LI> </OL> <P> <HR> <!--Navigation Panel--> <A NAME="tex2html1118" HREF="node70.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html1114" HREF="node68.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html1108" HREF="node68.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <A NAME="tex2html1116" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> <BR> <B> Next:</B> <A NAME="tex2html1119" HREF="node70.html">psb_cdins Communication</A> <B> Up:</B> <A NAME="tex2html1115" HREF="node68.html">Data management routines</A> <B> Previous:</B> <A NAME="tex2html1109" HREF="node68.html">Data management routines</A> <B> <A NAME="tex2html1117" HREF="node1.html">Contents</A></B> <!--End of Navigation Panel--> </BODY> </HTML>