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Fixed dates in docs.

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Salvatore Filippone
2017-07-24 11:11:25 +01:00
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@@ -54,15 +54,14 @@ original version by: Nikos Drakos, CBLU, University of Leeds
<H1><A NAME="SECTION00090000000000000000"></A><A NAME="sec:adding"></A>
<BR>
Adding new smoother and solver objects to MLD2P4
</H1>
</H1><FONT SIZE="+1"><FONT SIZE="+1"></FONT></FONT>
<P>
Developers can add completely new smoother and/or solver classes
<FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1">Developers can add completely new smoother and/or solver classes
derived from the base objects in the library (see Remark&nbsp;2 in Section&nbsp;<A HREF="node17.html#sec:precset">6.2</A>),
without recompiling the library itself.
</FONT></FONT></FONT>
<P>
To do so, it is necessary first to select the base type to be extended.
<FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1">To do so, it is necessary first to select the base type to be extended.
In our experience, it is quite likely that the new application needs
only the definition of a ``solver'' object, which is almost
always acting only on the local part of the distributed matrix.
@@ -71,11 +70,11 @@ are most often already provided by the block-Jacobi or the additive
Schwarz smoothers. To define a new solver, the developer will then
have to define its components and methods, perhaps taking one of the
predefined solvers as a starting point, if possible.
</FONT></FONT></FONT>
<P>
Once the new smoother/solver class has been developed, to use it in
<FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1">Once the new smoother/solver class has been developed, to use it in
the context of the multilevel preconditioners it is necessary to:
</FONT></FONT></FONT>
<UL>
<LI>declare in the application program a variable of the new type;
</LI>
@@ -89,21 +88,21 @@ following:
</LI>
<LI>link the code implementing the various methods into the application executable.
</LI>
</UL>
</UL><FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1">
The new solver object is then dynamically included in the
preconditioner structure, and acts as a <I>mold</I> to which the
preconditioner will conform, even though the MLD2P4 library has not
been modified to account for this new development.
</FONT></FONT></FONT>
<P>
It is possible to define new values for the keyword <code>WHAT</code> in the
<FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1">It is possible to define new values for the keyword <code>WHAT</code> in the
<code>set</code> routine; if the library code does not recognize a keyword,
it passes it down the composition hierarchy (levels containing
smoothers containing in turn solvers), so that it can be eventually caught by
the new solver.
</FONT></FONT></FONT>
<P>
An example is provided in the source code distribution under the
<FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1">An example is provided in the source code distribution under the
folder <code>tests/newslv</code>. In this example we are implementing a new
incomplete factorization variant (which is simply the ILU(0)
factorization under a new name). Because of the specifics of this case, it is
@@ -111,32 +110,36 @@ possible to reuse the basic structure of the ILU solver, with its
L/D/U components and the methods needed to apply the solver; only a
few methods, such as the description and most importantly the build,
need to be ovverridden (rewritten).
</FONT></FONT></FONT>
<P>
The interfaces for the calls shown above are defined using
<DIV ALIGN="CENTER">
<TABLE CELLPADDING=3>
<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=40><code>smoother</code></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><code>class(mld_x_base_smoother_type)</code></TD>
<FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1">The interfaces for the calls shown above are defined using
</FONT></FONT></FONT>
<DIV ALIGN="CENTER"><FONT SIZE="+1"><FONT SIZE="+1"></FONT></FONT><TABLE CELLPADDING=3>
<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=40><FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1">
<code>smoother</code> </FONT></FONT></FONT></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1"> <code>class(mld_x_base_smoother_type)</code> </FONT></FONT></FONT></TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=40>&nbsp;</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>The user-defined new smoother to be employed in the
preconditioner.</TD>
<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=40><FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1">
</FONT></FONT></FONT></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1"> The user-defined new smoother to be employed in the
preconditioner.</FONT></FONT></FONT></TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=40><code>solver</code></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><code>class(mld_x_base_solver_type)</code></TD>
<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=40><FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1">
<code>solver</code> </FONT></FONT></FONT></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1"> <code>class(mld_x_base_solver_type)</code> </FONT></FONT></FONT></TD>
</TR>
<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=40>&nbsp;</TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>The user-defined new solver to be employed in the
preconditioner.</TD>
<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=40><FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1">
</FONT></FONT></FONT></TD>
<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1"> The user-defined new solver to be employed in the
preconditioner.
</FONT></FONT></FONT></TD>
</TR>
</TABLE>
</DIV>
</TABLE><FONT SIZE="+1"><FONT SIZE="+1"></FONT></FONT></DIV><FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1">
The other arguments are defined in the way described in
Sec.&nbsp;<A HREF="node17.html#sec:precset">6.2</A>. As an example, in the <code>tests/newslv</code>
code we define a new object of type <code>mld_d_tlu_solver_type</code>, and
we pass it as follows:
<PRE>
</FONT></FONT></FONT><PRE>
! sparse matrix and preconditioner
type(psb_dspmat_type) :: a
type(mld_dprec_type) :: prec
@@ -152,8 +155,8 @@ we pass it as follows:
nlv = prec%get_nlevs()
call prec%set(tlusv, info,ilev=1,ilmax=max(1,nlv-1))
call prec%smoothers_build(a,desc_a,info)
</PRE>
<HR>
</PRE><FONT SIZE="+1"><FONT SIZE="+1"><FONT SIZE="+1">
</FONT></FONT></FONT><HR>
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