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<H1><A NAME="SECTION00080000000000000000"></A><A NAME="sec:userinterface"></A>
<BR>
User Interface
</H1><BIG CLASS="LARGE"><BIG CLASS="LARGE"></BIG></BIG>
<P>
<BIG CLASS="LARGE"><BIG CLASS="LARGE"><BIG CLASS="LARGE">The basic user interface of MLD2P4 consists of eight methods. The six
methods <code>init</code>, <code>set</code>, <code>build</code>,
<code>hierarchy_build</code>, <code>smoothers_build</code> and <code>apply</code>
encapsulate all the functionalities for the setup and the application
of any multilevel and one-level preconditioner implemented in the
package.
The method <code>free</code> deallocates the preconditioner data structure, while
<code>descr</code> prints a description of the preconditioner setup by the user.
For backward compatibility, methods are also accessible as
stand-alone subroutines.
</BIG></BIG></BIG>
<P>
<BIG CLASS="LARGE"><BIG CLASS="LARGE"><BIG CLASS="LARGE">For each method, the same user interface is overloaded with
respect to the real/ complex case and the single/double precision;
arguments with appropriate data types must be passed to the method,
i.e.,
</BIG></BIG></BIG>
<UL>
<LI>the sparse matrix data structure, containing the matrix to be
preconditioned, must be of type <code>psb_</code><SPAN CLASS="textit">x</SPAN><code>spmat_type</code>
with <SPAN CLASS="textit">x</SPAN> = <code>s</code> for real single precision, <SPAN CLASS="textit">x</SPAN> = <code>d</code>
for real double precision, <SPAN CLASS="textit">x</SPAN> = <code>c</code> for complex single precision,
<SPAN CLASS="textit">x</SPAN> = <code>z</code> for complex double precision;
</LI>
<LI>the preconditioner data structure must be of type
<code>mld_</code><SPAN CLASS="textit">x</SPAN><code>prec_type</code>, with <SPAN CLASS="textit">x</SPAN> =
<code>s</code>, <code>d</code>, <code>c</code>, <code>z</code>, according to the sparse
matrix data structure;
</LI>
<LI>the arrays containing the vectors <SPAN CLASS="MATH"><IMG
WIDTH="14" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
SRC="img72.png"
ALT="$v$"></SPAN> and <SPAN CLASS="MATH"><IMG
WIDTH="17" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
SRC="img73.png"
ALT="$w$"></SPAN> involved in
the preconditioner application <SPAN CLASS="MATH"><IMG
WIDTH="82" HEIGHT="21" ALIGN="BOTTOM" BORDER="0"
SRC="img23.png"
ALT="$w=B^{-1}v$"></SPAN> must be of type
<code>psb_</code><SPAN CLASS="textit">x</SPAN><code>vect_type</code> with <SPAN CLASS="textit">x</SPAN> =
<code>s</code>, <code>d</code>, <code>c</code>, <code>z</code>, in a manner completely
analogous to the sparse matrix type;
</LI>
<LI>real parameters defining the preconditioner must be declared
according to the precision of the sparse matrix and preconditioner
data structures (see Section <A HREF="node20.html#sec:precset">6.2</A>).
</LI>
</UL><BIG CLASS="LARGE"><BIG CLASS="LARGE"><BIG CLASS="LARGE">
A description of each method is given in the remainder of this section.
</BIG></BIG></BIG>
<P>
<BIG CLASS="LARGE"><BIG CLASS="LARGE"></BIG></BIG>
<P>
<BIG CLASS="LARGE"><BIG CLASS="LARGE"></BIG></BIG>
<BR><HR>
<!--Table of Child-Links-->
<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></A>
<UL CLASS="ChildLinks">
<LI><A NAME="tex2html308"
HREF="node19.html">Method init</A>
<LI><A NAME="tex2html309"
HREF="node20.html">Method set</A>
<LI><A NAME="tex2html310"
HREF="node21.html">Method hierarchy_build</A>
<LI><A NAME="tex2html311"
HREF="node22.html">Method smoothers_build</A>
<LI><A NAME="tex2html312"
HREF="node23.html">Method build</A>
<LI><A NAME="tex2html313"
HREF="node24.html">Method apply</A>
<LI><A NAME="tex2html314"
HREF="node25.html">Method free</A>
<LI><A NAME="tex2html315"
HREF="node26.html">Method descr</A>
<LI><A NAME="tex2html316"
HREF="node27.html">Auxiliary Methods</A>
<UL>
<LI><A NAME="tex2html317"
HREF="node28.html">Method: dump</A>
<LI><A NAME="tex2html318"
HREF="node29.html">Method: clone</A>
<LI><A NAME="tex2html319"
HREF="node30.html">Method: sizeof</A>
<LI><A NAME="tex2html320"
HREF="node31.html">Method: allocate_wrk</A>
<LI><A NAME="tex2html321"
HREF="node32.html">Method: free_wrk</A>
</UL></UL>
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