<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html > <head><title>init — Initialize a preconditioner</title> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> <meta name="generator" content="TeX4ht (http://www.tug.org/tex4ht/)"> <meta name="originator" content="TeX4ht (http://www.tug.org/tex4ht/)"> <!-- html,3 --> <meta name="src" content="userhtml.tex"> <link rel="stylesheet" type="text/css" href="userhtml.css"> </head><body > <!--l. 26--><div class="crosslinks"><p class="noindent">[<a href="userhtmlsu89.html" >next</a>] [<a href="userhtmlsu82.html#tailuserhtmlsu84.html">tail</a>] [<a href="userhtmlsu86.html#userhtmlsu87.html" >up</a>] </p></div> <h4 class="subsectionHead"><span class="titlemark">10.1 </span> <a id="x99-13600010.1"></a>init — Initialize a preconditioner</h4> <div class="verbatim" id="verbatim-102"> call prec%init(icontxt,ptype, info) </div> <!--l. 30--><p class="nopar" > <!--l. 32--><p class="indent" > <dl class="description"><dt class="description"> <span class="cmbx-10">Type:</span> </dt><dd class="description">Asynchronous. </dd><dt class="description"> <span class="cmbx-10">On Entry</span> </dt><dd class="description"> </dd><dt class="description"> <span class="cmbx-10">icontxt</span> </dt><dd class="description">the communication context.<br class="newline" />Scope:<span class="cmbx-10">global</span>.<br class="newline" />Type:<span class="cmbx-10">required</span>.<br class="newline" />Intent: <span class="cmbx-10">in</span>.<br class="newline" />Specified as: an integer value. </dd><dt class="description"> <span class="cmbx-10">ptype</span> </dt><dd class="description">the type of preconditioner. Scope: <span class="cmbx-10">global </span><br class="newline" />Type: <span class="cmbx-10">required</span><br class="newline" />Intent: <span class="cmbx-10">in</span>.<br class="newline" />Specified as: a character string, see usage notes. </dd><dt class="description"> <span class="cmbx-10">On Exit</span> </dt><dd class="description"> </dd><dt class="description"> <span class="cmbx-10">prec</span> </dt><dd class="description">Scope: <span class="cmbx-10">local </span><br class="newline" />Type: <span class="cmbx-10">required</span><br class="newline" />Intent: <span class="cmbx-10">inout</span>.<br class="newline" />Specified as: a preconditioner data structure <a href="userhtmlsu8.html#precdata"><span class="cmtt-10">psb</span><span class="cmtt-10">_prec</span><span class="cmtt-10">_type</span></a>. </dd><dt class="description"> <span class="cmbx-10">info</span> </dt><dd class="description">Scope: <span class="cmbx-10">global </span><br class="newline" />Type: <span class="cmbx-10">required</span><br class="newline" />Intent: <span class="cmbx-10">out</span>.<br class="newline" />Error code: if no error, 0 is returned.</dd></dl> <!--l. 66--><p class="noindent" ><span class="cmbx-12">Notes </span>Legal inputs to this subroutine are interpreted depending on the <span class="cmmi-10">ptype </span>string as follows<span class="footnote-mark"><a href="userhtml100.html#fn4x0"><sup class="textsuperscript">4</sup></a></span><a id="x99-136001f4"></a> : <dl class="description"><dt class="description"> <span class="cmbx-10">NONE</span> </dt><dd class="description">No preconditioning, i.e. the preconditioner is just a copy operator. </dd><dt class="description"> <span class="cmbx-10">DIAG</span> </dt><dd class="description">Diagonal scaling; each entry of the input vector is multiplied by the reciprocal of the sum of the absolute values of the coefficients in the corresponding row of matrix <span class="cmmi-10">A</span>; </dd><dt class="description"> <span class="cmbx-10">BJAC</span> </dt><dd class="description">Precondition by a factorization of the block-diagonal of matrix <span class="cmmi-10">A</span>, where block boundaries are determined by the data allocation boundaries for each process; requires no communication. Only the incomplete factorization <span class="cmmi-10">ILU</span>(0) is currently implemented.</dd></dl> <!--l. 87--><div class="crosslinks"><p class="noindent">[<a href="userhtmlsu89.html" >next</a>] [<a href="userhtmlsu84.html" >front</a>] [<a href="userhtmlsu86.html#userhtmlsu87.html" >up</a>] </p></div> <!--l. 87--><p class="indent" > <a id="tailuserhtmlsu84.html"></a> </body></html>