You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
122 lines
4.1 KiB
HTML
122 lines
4.1 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
|
|
|
|
<!--Converted with LaTeX2HTML 2017.2 (Released Jan 23, 2017) -->
|
|
<HTML>
|
|
<HEAD>
|
|
<TITLE>Programming model</TITLE>
|
|
<META NAME="description" CONTENT="Programming model">
|
|
<META NAME="keywords" CONTENT="userhtml">
|
|
<META NAME="resource-type" CONTENT="document">
|
|
<META NAME="distribution" CONTENT="global">
|
|
|
|
<META NAME="Generator" CONTENT="LaTeX2HTML v2017.2">
|
|
<META HTTP-EQUIV="Content-Style-Type" CONTENT="text/css">
|
|
|
|
<LINK REL="STYLESHEET" HREF="userhtml.css">
|
|
|
|
<LINK REL="previous" HREF="node6.html">
|
|
<LINK REL="up" HREF="node3.html">
|
|
<LINK REL="next" HREF="node9.html">
|
|
</HEAD>
|
|
|
|
<BODY >
|
|
|
|
<DIV CLASS="navigation"><!--Navigation Panel-->
|
|
<A NAME="tex2html287"
|
|
HREF="node9.html">
|
|
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A>
|
|
<A NAME="tex2html283"
|
|
HREF="node3.html">
|
|
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A>
|
|
<A NAME="tex2html279"
|
|
HREF="node7.html">
|
|
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A>
|
|
<A NAME="tex2html285"
|
|
HREF="node1.html">
|
|
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A>
|
|
<BR>
|
|
<B> Next:</B> <A NAME="tex2html288"
|
|
HREF="node9.html">Data Structures and Classes</A>
|
|
<B> Up:</B> <A NAME="tex2html284"
|
|
HREF="node3.html">General overview</A>
|
|
<B> Previous:</B> <A NAME="tex2html280"
|
|
HREF="node7.html">User-defined index mappings</A>
|
|
<B> <A NAME="tex2html286"
|
|
HREF="node1.html">Contents</A></B>
|
|
<BR>
|
|
<BR></DIV>
|
|
<!--End of Navigation Panel-->
|
|
|
|
<H2><A NAME="SECTION00034000000000000000">
|
|
Programming model</A>
|
|
</H2>
|
|
|
|
<P>
|
|
The PSBLAS librarary is based on the Single Program Multiple Data
|
|
(SPMD) programming model: each process participating in the
|
|
computation performs the same actions on a chunk of data. Parallelism
|
|
is thus data-driven.
|
|
|
|
<P>
|
|
Because of this structure, many subroutines coordinate their action
|
|
across the various processes, thus providing an implicit
|
|
synchronization point, and therefore <SPAN CLASS="textit">must</SPAN> be
|
|
called simultaneously by all processes participating in the
|
|
computation. This is certainly true for the data allocation and
|
|
assembly routines, for all the computational routines and for some of
|
|
the tools routines.
|
|
|
|
<P>
|
|
However there are many cases where no synchronization, and indeed no
|
|
communication among processes, is implied; for instance, all the routines in
|
|
sec. <A HREF="node9.html#sec:datastruct">3</A> are only acting on the local data structures,
|
|
and thus may be called independently. The most important case is that
|
|
of the coefficient insertion routines: since the number of
|
|
coefficients in the sparse and dense matrices varies among the
|
|
processors, and since the user is free to choose an arbitrary order in
|
|
builiding the matrix entries, these routines cannot imply a
|
|
synchronization.
|
|
|
|
<P>
|
|
Throughout this user's guide each subroutine will be clearly indicated
|
|
as:
|
|
<DL>
|
|
<DT><STRONG>Synchronous:</STRONG></DT>
|
|
<DD>must be called simultaneously by all the
|
|
processes in the relevant communication context;
|
|
</DD>
|
|
<DT><STRONG>Asynchronous:</STRONG></DT>
|
|
<DD>may be called in a totally independent manner.
|
|
</DD>
|
|
</DL>
|
|
|
|
<P>
|
|
|
|
<DIV CLASS="navigation"><HR>
|
|
<!--Navigation Panel-->
|
|
<A NAME="tex2html287"
|
|
HREF="node9.html">
|
|
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A>
|
|
<A NAME="tex2html283"
|
|
HREF="node3.html">
|
|
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A>
|
|
<A NAME="tex2html279"
|
|
HREF="node7.html">
|
|
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A>
|
|
<A NAME="tex2html285"
|
|
HREF="node1.html">
|
|
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A>
|
|
<BR>
|
|
<B> Next:</B> <A NAME="tex2html288"
|
|
HREF="node9.html">Data Structures and Classes</A>
|
|
<B> Up:</B> <A NAME="tex2html284"
|
|
HREF="node3.html">General overview</A>
|
|
<B> Previous:</B> <A NAME="tex2html280"
|
|
HREF="node7.html">User-defined index mappings</A>
|
|
<B> <A NAME="tex2html286"
|
|
HREF="node1.html">Contents</A></B> </DIV>
|
|
<!--End of Navigation Panel-->
|
|
|
|
</BODY>
|
|
</HTML>
|