<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <!--Converted with LaTeX2HTML 2018 (Released Feb 1, 2018) --> <HTML> <HEAD> <TITLE>psb_spall -- Allocates a sparse matrix</TITLE> <META NAME="description" CONTENT="psb_spall -- Allocates a sparse matrix"> <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="node79.html"> <LINK REL="previous" HREF="node77.html"> <LINK REL="up" HREF="node71.html"> <LINK REL="next" HREF="node79.html"> </HEAD> <BODY > <DIV CLASS="navigation"><!--Navigation Panel--> <A NAME="tex2html1238" HREF="node79.html"> <IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A> <A NAME="tex2html1234" HREF="node71.html"> <IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A> <A NAME="tex2html1228" HREF="node77.html"> <IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A> <A NAME="tex2html1236" HREF="node1.html"> <IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A> <BR> <B> Next:</B> <A NAME="tex2html1239" HREF="node79.html">psb_spins Insert</A> <B> Up:</B> <A NAME="tex2html1235" HREF="node71.html">Data management routines</A> <B> Previous:</B> <A NAME="tex2html1229" HREF="node77.html">psb_cdbldext Build</A> <B> <A NAME="tex2html1237" HREF="node1.html">Contents</A></B> <BR> <BR></DIV> <!--End of Navigation Panel--> <H2><A NAME="SECTION00077000000000000000"> psb_spall -- Allocates a sparse matrix</A> </H2> <P> <PRE> call psb_spall(a, desc_a, info, nnz) </PRE> <P> <DL> <DT><STRONG>Type:</STRONG></DT> <DD>Synchronous. </DD> <DT><STRONG><B>On Entry</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>in</B>. <BR> Specified as: a structured data of type descdata<TT>psb_desc_type</TT>. </DD> <DT><STRONG>nnz</STRONG></DT> <DD>An estimate of the number of nonzeroes in the local part of the assembled matrix. <BR> Scope: <B>global</B>. <BR> Type: <B>optional</B>. <BR> Intent: <B>in</B>. <BR> Specified as: an integer value. </DD> </DL> <P> <DL> <DT><STRONG><B>On Return</B></STRONG></DT> <DD> </DD> <DT><STRONG>a</STRONG></DT> <DD>the matrix to be allocated. <BR> Scope:<B>local</B> <BR> Type:<B>required</B> <BR> Intent: <B>out</B>. <BR> Specified as: a structured data of type spdata<TT>psb_Tspmat_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> <BIG CLASS="LARGE"><B>Notes</B></BIG> <OL> <LI>On exit from this routine the sparse matrix is in the build state. </LI> <LI>The descriptor may be in either the build or assembled state. </LI> <LI>Providing a good estimate for the number of nonzeroes <SPAN CLASS="MATH"><IMG WIDTH="32" HEIGHT="13" ALIGN="BOTTOM" BORDER="0" SRC="img107.png" ALT="$nnz$"></SPAN> in the assembled matrix may substantially improve performance in the matrix build phase, as it will reduce or eliminate the need for (potentially multiple) data reallocations. </LI> </OL> <P> <BR><HR> </BODY> </HTML>