|
|
|
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
|
|
|
|
|
|
|
|
|
|
<!--Converted with LaTeX2HTML 2018 (Released Feb 1, 2018) -->
|
|
|
|
|
<HTML>
|
|
|
|
|
<HEAD>
|
|
|
|
|
<TITLE>psb_nrm2 -- Global 2-norm reduction</TITLE>
|
|
|
|
|
<META NAME="description" CONTENT="psb_nrm2 -- Global 2-norm reduction">
|
|
|
|
|
<META NAME="keywords" CONTENT="userhtml">
|
|
|
|
|
<META NAME="resource-type" CONTENT="document">
|
|
|
|
|
<META NAME="distribution" CONTENT="global">
|
|
|
|
|
|
|
|
|
|
<META NAME="Generator" CONTENT="LaTeX2HTML v2018">
|
|
|
|
|
<META HTTP-EQUIV="Content-Style-Type" CONTENT="text/css">
|
|
|
|
|
|
|
|
|
|
<LINK REL="STYLESHEET" HREF="userhtml.css">
|
|
|
|
|
|
|
|
|
|
<LINK REL="next" HREF="node115.html">
|
|
|
|
|
<LINK REL="previous" HREF="node113.html">
|
|
|
|
|
<LINK REL="up" HREF="node99.html">
|
|
|
|
|
<LINK REL="next" HREF="node115.html">
|
|
|
|
|
</HEAD>
|
|
|
|
|
|
|
|
|
|
<BODY >
|
|
|
|
|
|
|
|
|
|
<DIV CLASS="navigation"><!--Navigation Panel-->
|
|
|
|
|
<A NAME="tex2html1685"
|
|
|
|
|
HREF="node115.html">
|
|
|
|
|
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A>
|
|
|
|
|
<A NAME="tex2html1681"
|
|
|
|
|
HREF="node99.html">
|
|
|
|
|
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A>
|
|
|
|
|
<A NAME="tex2html1675"
|
|
|
|
|
HREF="node113.html">
|
|
|
|
|
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A>
|
|
|
|
|
<A NAME="tex2html1683"
|
|
|
|
|
HREF="node1.html">
|
|
|
|
|
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A>
|
|
|
|
|
<BR>
|
|
|
|
|
<B> Next:</B> <A NAME="tex2html1686"
|
|
|
|
|
HREF="node115.html">psb_snd Send</A>
|
|
|
|
|
<B> Up:</B> <A NAME="tex2html1682"
|
|
|
|
|
HREF="node99.html">Parallel environment routines</A>
|
|
|
|
|
<B> Previous:</B> <A NAME="tex2html1676"
|
|
|
|
|
HREF="node113.html">psb_amn Global</A>
|
|
|
|
|
<B> <A NAME="tex2html1684"
|
|
|
|
|
HREF="node1.html">Contents</A></B>
|
|
|
|
|
<BR>
|
|
|
|
|
<BR></DIV>
|
|
|
|
|
<!--End of Navigation Panel-->
|
|
|
|
|
|
|
|
|
|
<H2><A NAME="SECTION000815000000000000000">
|
|
|
|
|
psb_nrm2 -- Global 2-norm reduction</A>
|
|
|
|
|
</H2>
|
|
|
|
|
|
|
|
|
|
<P>
|
|
|
|
|
<PRE>
|
|
|
|
|
call psb_nrm2(icontxt, dat, root)
|
|
|
|
|
</PRE>
|
|
|
|
|
|
|
|
|
|
<P>
|
|
|
|
|
This subroutine implements a 2-norm value reduction
|
|
|
|
|
operation based on the underlying communication library.
|
|
|
|
|
<DL>
|
|
|
|
|
<DT><STRONG>Type:</STRONG></DT>
|
|
|
|
|
<DD>Synchronous.
|
|
|
|
|
</DD>
|
|
|
|
|
<DT><STRONG><B>On Entry </B></STRONG></DT>
|
|
|
|
|
<DD>
|
|
|
|
|
</DD>
|
|
|
|
|
<DT><STRONG>icontxt</STRONG></DT>
|
|
|
|
|
<DD>the communication context identifying the virtual
|
|
|
|
|
parallel machine.
|
|
|
|
|
<BR>
|
|
|
|
|
Scope: <B>global</B>.
|
|
|
|
|
<BR>
|
|
|
|
|
Type: <B>required</B>.
|
|
|
|
|
<BR>
|
|
|
|
|
Intent: <B>in</B>.
|
|
|
|
|
<BR>
|
|
|
|
|
Specified as: an integer variable.
|
|
|
|
|
</DD>
|
|
|
|
|
<DT><STRONG>dat</STRONG></DT>
|
|
|
|
|
<DD>The local contribution to the global minimum.
|
|
|
|
|
<BR>
|
|
|
|
|
Scope: <B>local</B>.
|
|
|
|
|
<BR>
|
|
|
|
|
Type: <B>required</B>.
|
|
|
|
|
<BR>
|
|
|
|
|
Intent: <B>inout</B>.
|
|
|
|
|
<BR>
|
|
|
|
|
Specified as: a real variable, which may be a
|
|
|
|
|
scalar, or a rank 1 array. Kind, rank and size must agree on all processes.
|
|
|
|
|
</DD>
|
|
|
|
|
<DT><STRONG>root</STRONG></DT>
|
|
|
|
|
<DD>Process to hold the final value, or <SPAN CLASS="MATH"><IMG
|
|
|
|
|
WIDTH="24" HEIGHT="30" ALIGN="MIDDLE" BORDER="0"
|
|
|
|
|
SRC="img82.png"
|
|
|
|
|
ALT="$-1$"></SPAN> to make it available
|
|
|
|
|
on all processes.
|
|
|
|
|
<BR>
|
|
|
|
|
Scope: <B>global</B>.
|
|
|
|
|
<BR>
|
|
|
|
|
Type: <B>optional</B>.
|
|
|
|
|
<BR>
|
|
|
|
|
Intent: <B>in</B>.
|
|
|
|
|
<BR>
|
|
|
|
|
Specified as: an integer value <!-- MATH
|
|
|
|
|
$-1<= root <= np-1$
|
|
|
|
|
-->
|
|
|
|
|
<SPAN CLASS="MATH"><IMG
|
|
|
|
|
WIDTH="165" HEIGHT="30" ALIGN="MIDDLE" BORDER="0"
|
|
|
|
|
SRC="img141.png"
|
|
|
|
|
ALT="$-1<= root <= np-1$"></SPAN>, default -1.
|
|
|
|
|
<BR></DD>
|
|
|
|
|
</DL>
|
|
|
|
|
|
|
|
|
|
<P>
|
|
|
|
|
<DL>
|
|
|
|
|
<DT><STRONG><B>On Return</B></STRONG></DT>
|
|
|
|
|
<DD>
|
|
|
|
|
</DD>
|
|
|
|
|
<DT><STRONG>dat</STRONG></DT>
|
|
|
|
|
<DD>On destination process(es), the result of the 2-norm reduction.
|
|
|
|
|
<BR>
|
|
|
|
|
Scope: <B>global</B>.
|
|
|
|
|
<BR>
|
|
|
|
|
Type: <B>required</B>.
|
|
|
|
|
<BR>
|
|
|
|
|
Intent: <B>inout</B>.
|
|
|
|
|
<BR>
|
|
|
|
|
Specified as: a real variable, which may be a
|
|
|
|
|
scalar, or a rank 1 array.
|
|
|
|
|
<BR>
|
|
|
|
|
Kind, rank and size must agree on all processes.
|
|
|
|
|
</DD>
|
|
|
|
|
</DL>
|
|
|
|
|
|
|
|
|
|
<P>
|
|
|
|
|
<BIG CLASS="LARGE"><B>Notes</B></BIG>
|
|
|
|
|
|
|
|
|
|
<OL>
|
|
|
|
|
<LI>This reduction is appropriate to compute the results of multiple
|
|
|
|
|
(local) NRM2 operations at the same time.
|
|
|
|
|
</LI>
|
|
|
|
|
<LI>Denoting by <SPAN CLASS="MATH"><IMG
|
|
|
|
|
WIDTH="32" HEIGHT="30" ALIGN="MIDDLE" BORDER="0"
|
|
|
|
|
SRC="img142.png"
|
|
|
|
|
ALT="$dat_i$"></SPAN> the value of the variable <SPAN CLASS="MATH"><IMG
|
|
|
|
|
WIDTH="26" HEIGHT="14" ALIGN="BOTTOM" BORDER="0"
|
|
|
|
|
SRC="img143.png"
|
|
|
|
|
ALT="$dat$"></SPAN> on process
|
|
|
|
|
<SPAN CLASS="MATH"><IMG
|
|
|
|
|
WIDTH="9" HEIGHT="17" ALIGN="BOTTOM" BORDER="0"
|
|
|
|
|
SRC="img4.png"
|
|
|
|
|
ALT="$i$"></SPAN>, the output <SPAN CLASS="MATH"><IMG
|
|
|
|
|
WIDTH="27" HEIGHT="13" ALIGN="BOTTOM" BORDER="0"
|
|
|
|
|
SRC="img29.png"
|
|
|
|
|
ALT="$res$"></SPAN> is equivalent to the computation of
|
|
|
|
|
<BR><P></P>
|
|
|
|
|
<DIV ALIGN="CENTER" CLASS="mathdisplay">
|
|
|
|
|
<!-- MATH
|
|
|
|
|
\begin{displaymath}
|
|
|
|
|
res = \sqrt{\sum_i dat_i^2},
|
|
|
|
|
\end{displaymath}
|
|
|
|
|
-->
|
|
|
|
|
|
|
|
|
|
<IMG
|
|
|
|
|
WIDTH="119" HEIGHT="55" BORDER="0"
|
|
|
|
|
SRC="img144.png"
|
|
|
|
|
ALT="\begin{displaymath}res = \sqrt{\sum_i dat_i^2},\end{displaymath}">
|
|
|
|
|
</DIV>
|
|
|
|
|
<BR CLEAR="ALL">
|
|
|
|
|
<P></P>
|
|
|
|
|
with care taken to avoid unnecessary overflow.
|
|
|
|
|
</LI>
|
|
|
|
|
<LI>The <code>dat</code> argument is both input and output, and its
|
|
|
|
|
value may be changed even on processes different from the final
|
|
|
|
|
result destination.
|
|
|
|
|
</LI>
|
|
|
|
|
</OL>
|
|
|
|
|
|
|
|
|
|
<P>
|
|
|
|
|
|
|
|
|
|
<DIV CLASS="navigation"><HR>
|
|
|
|
|
<!--Navigation Panel-->
|
|
|
|
|
<A NAME="tex2html1685"
|
|
|
|
|
HREF="node115.html">
|
|
|
|
|
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A>
|
|
|
|
|
<A NAME="tex2html1681"
|
|
|
|
|
HREF="node99.html">
|
|
|
|
|
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A>
|
|
|
|
|
<A NAME="tex2html1675"
|
|
|
|
|
HREF="node113.html">
|
|
|
|
|
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A>
|
|
|
|
|
<A NAME="tex2html1683"
|
|
|
|
|
HREF="node1.html">
|
|
|
|
|
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A>
|
|
|
|
|
<BR>
|
|
|
|
|
<B> Next:</B> <A NAME="tex2html1686"
|
|
|
|
|
HREF="node115.html">psb_snd Send</A>
|
|
|
|
|
<B> Up:</B> <A NAME="tex2html1682"
|
|
|
|
|
HREF="node99.html">Parallel environment routines</A>
|
|
|
|
|
<B> Previous:</B> <A NAME="tex2html1676"
|
|
|
|
|
HREF="node113.html">psb_amn Global</A>
|
|
|
|
|
<B> <A NAME="tex2html1684"
|
|
|
|
|
HREF="node1.html">Contents</A></B> </DIV>
|
|
|
|
|
<!--End of Navigation Panel-->
|
|
|
|
|
|
|
|
|
|
</BODY>
|
|
|
|
|
</HTML>
|
