mld2p4-2:

docs/html/img100.png docs/html/img101.png docs/html/img102.png docs/html/img103.png docs/html/img104.png docs/html/img105.png docs/html/img106.png docs/html/img107.png docs/html/img108.png docs/html/img93.png docs/html/img94.png docs/html/img95.png docs/html/img96.png docs/html/img97.png docs/html/img98.png docs/html/img99.png docs/html/node17.html docs/html/node18.html docs/html/node20.html docs/html/node26.html docs/mld2p4-2.1-guide.pdf docs/src/userinterface.tex tests/pdegen/runs/ppde.inp Update docs with new aggregation and solvers.
2026-10-06 14:44:55 +00:00 · 2016-05-23 08:44:34 +00:00
parent 111313d3c6
commit f6d0f6de23
23 changed files with 597 additions and 387 deletions
@@ -100,9 +100,12 @@ according to the preconditioner type chosen by the user.
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><code>integer, optional, intent(in)</code>.</TD>
 </TR>
 <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34>&nbsp;</TD>
-<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>The number of levels of the multilevel preconditioner.
-                If <code>nlev</code> is not present and <code>ptype</code>=<code>'ML'</code>, <code>'ml'</code>, 
-                then <code>nlev</code>=2 is assumed. Otherwise, <code>nlev</code> is ignored.</TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>The number of levels of the multilevel
+                preconditioner. This optional argument is deprecated,
+                new codes should set the number of levels with <code>mld_precset</code>.</TD>
+</TR>
+<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34></TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>&nbsp;</TD>
 </TR>
 </TABLE>

@@ -85,7 +85,7 @@ variable of the new  type in the main program, it is possible to pass
 the new smoother/solver variable  to the setup routine as follows:
 <DIV ALIGN="CENTER">
 <code>call p%set(smoother,info [,ilev ,pos])</code>
-<BR><code>call p%set(solver,info [,ilev ,poss])</code>
+<BR><code>call p%set(solver,info [,ilev ,pos])</code>

 </DIV>
 In this way, the variable will act as a <I>mold</I> to which the
@@ -147,6 +147,13 @@ modified, and thus has no direct knowledge about the new type.
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>Error code. If no error, 0 is returned. See Section&nbsp;<A HREF="node23.html#sec:errors">7</A>
                for details.</TD>
 </TR>
+<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34><code>pos</code></TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340><code>charater(len=*), intent(in)</code>.</TD>
+</TR>
+<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34>&nbsp;</TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>Whether the other arguments apply to the <code>'PRE'</code>
+                or to the <code>'POST'</code> smoothers.</TD>
+</TR>
 </TABLE>

 <P>
@@ -202,7 +209,7 @@ according to their needs.

 <P>
 <BR><P></P>
-<DIV ALIGN="CENTER"><A NAME="1306"></A>
+<DIV ALIGN="CENTER"><A NAME="1312"></A>
 <TABLE>
 <CAPTION><STRONG>Table 2:</STRONG>
 Parameters defining the type of multi-level preconditioner.
@@ -246,7 +253,7 @@ Parameters defining the type of multi-level preconditioner.

 <P>
 <BR><P></P>
-<DIV ALIGN="CENTER"><A NAME="1308"></A>
+<DIV ALIGN="CENTER"><A NAME="1314"></A>
 <TABLE>
 <CAPTION><STRONG>Table 3:</STRONG>
 Parameters defining the one-level preconditioner used as smoother.
@@ -366,7 +373,7 @@ Parameters defining the one-level preconditioner used as smoother.

 <P>
 <BR><P></P>
-<DIV ALIGN="CENTER"><A NAME="1310"></A>
+<DIV ALIGN="CENTER"><A NAME="1316"></A>
 <TABLE>
 <CAPTION><STRONG>Table 4:</STRONG>
 Parameters defining the aggregation algorithm.
@@ -383,21 +390,54 @@ Parameters defining the aggregation algorithm.
 <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=142><code>mld_coarse_aggr_size_</code>  <BR><code>COARSE_AGGR_SIZE</code></TD>
 <TD ALIGN="LEFT"><code>integer</code></TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68>A positive number</TD>
-<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68>0, meaning that the size is fixed at
-                         <code>precinit</code> time</TD>
-<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=170>Coarse size threshold. Disregard the
-                         original specification of number of levels in
-                         <code>precinit</code> and continue aggregation
-                         until either the global number of variables
-                         is below this threshold, or the aggregation
-                         does not reduce the size any longer.</TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68>The  cubic root of 
+                           the matrix size at the fine level.</TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=170>Coarse size threshold. Aggregation will
+                           proceed  until either the global number of
+                           variables is below this threshold, or the
+                           aggregation  does not reduce the size any
+                           longer, or the maximum number of levels is
+                           reached.</TD>
+</TR>
+<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=142><code>mld_min_aggr_ratio</code>  <BR><code>MIN_AGGR_RATIO</code></TD>
+<TD ALIGN="LEFT"><code>real</code></TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68>A number greater than one</TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68>1.5</TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=170>Minimum aggregation ratio. Aggregation will
+                           stop if the ratio between the matrix sizes
+                           at two consecutive levels drops below this
+                           threshold.</TD>
+</TR>
+<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=142><code>mld_n_prec_levs_</code>  <BR><code>N_PREC_LEVS</code></TD>
+<TD ALIGN="LEFT"><code>integer</code></TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68>A number greater than 1, or -1.</TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68>-1</TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=170>Number of levels; if set to a positive
+                           number greater than 1, it will force the
+                           aggregation algorithm to use this many
+                           levels (unless there is no reduction in the
+                           coarse matrix size).</TD>
+</TR>
+<TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=142><code>mld_max_prec_levs_</code>  <BR><code>MAX_PREC_LEVS</code></TD>
+<TD ALIGN="LEFT"><code>integer</code></TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68>A positive number</TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68>20</TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=170>Maximum number of levels: irrespective of
+                           the other settings, do not use more than
+                           this many levels.</TD>
 </TR>
 <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=142><code>mld_aggr_alg_</code>  <BR><code>AGGR_ALG</code></TD>
 <TD ALIGN="LEFT"><code>character(len=*)</code></TD>
-<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68><TT>'DEC'</TT></TD>
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68><TT>'DEC'</TT>, <TT>'SYMDEC'</TT></TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68><TT>'DEC'</TT></TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=170>Aggregation algorithm. Currently, only the
-                         decoupled aggregation is available.</TD>
+                         decoupled aggregation is available; the
+                           <code>SYMDEC</code> option  applies decoupled
+                           aggregation to  the sparsity pattern
+                           of <IMG
+ WIDTH="62" HEIGHT="40" ALIGN="MIDDLE" BORDER="0"
+ SRC="img93.png"
+ ALT="$A+A^T$">.</TD>
 </TR>
 <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=142><code>mld_aggr_ord_</code>  <BR><code>AGGR_ORD</code></TD>
 <TD ALIGN="LEFT"><code>character(len=*)</code></TD>
@@ -420,28 +460,28 @@ Parameters defining the aggregation algorithm.
 <TD ALIGN="LEFT"><code>real(</code><I>kind_parameter</I><code>)</code></TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68>Any&nbsp;real&nbsp;num. <IMG
 WIDTH="56" HEIGHT="36" ALIGN="MIDDLE" BORDER="0"
- SRC="img93.png"
+ SRC="img94.png"
 ALT="$\in [0, 1]$"></TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68>0.05</TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=170>Threshold <IMG
 WIDTH="13" HEIGHT="16" ALIGN="BOTTOM" BORDER="0"
- SRC="img94.png"
+ SRC="img95.png"
 ALT="$\theta$"> in the aggregation algorithm.</TD>
 </TR>
 <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=142><code>mld_aggr_scale_</code> <BR><code>AGGR_SCALE</code></TD>
 <TD ALIGN="LEFT"><code>real(</code><I>kind_parameter</I><code>)</code></TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68>Any&nbsp;real&nbsp;num. <IMG
 WIDTH="56" HEIGHT="36" ALIGN="MIDDLE" BORDER="0"
- SRC="img93.png"
+ SRC="img94.png"
 ALT="$\in [0, 1]$"></TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=68>1.0</TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=170>Scale factor applied to the threshold going
- from level <IMG
+                           from level <IMG
 WIDTH="33" HEIGHT="16" ALIGN="BOTTOM" BORDER="0"
- SRC="img95.png"
+ SRC="img96.png"
 ALT="$ilev$"> to level <IMG
 WIDTH="63" HEIGHT="34" ALIGN="MIDDLE" BORDER="0"
- SRC="img96.png"
+ SRC="img97.png"
 ALT="$ilev+1$">.</TD>
 </TR>
 <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=142><code>mld_aggr_omega_alg_</code>  <BR><code>AGGR_OMEGA_ALG</code></TD>
@@ -452,13 +492,13 @@ Parameters defining the aggregation algorithm.
 WIDTH="16" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
 SRC="img86.png"
 ALT="$\omega$"> in the
-                         smoothed aggregation should be computed:
-                         either via an estimate of the spectral radius of
-                         <IMG
+                           smoothed aggregation should be computed:
+                           either via an estimate of the spectral radius of
+                           <IMG
 WIDTH="50" HEIGHT="21" ALIGN="BOTTOM" BORDER="0"
 SRC="img87.png"
 ALT="$D^{-1}A$">, or explicily
-                         specified by the user.</TD>
+                           specified by the user.</TD>
 </TR>
 <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=142><code>mld_aggr_eig_</code>  <BR><code>AGGR_EIG</code></TD>
 <TD ALIGN="LEFT"><code>character(len=*)</code></TD>
@@ -479,7 +519,7 @@ Parameters defining the aggregation algorithm.
 -->
 <IMG
 WIDTH="113" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
- SRC="img97.png"
+ SRC="img98.png"
 ALT="$4/(3\rho(D^{-1}A))$"></TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=170>Damping parameter <IMG
 WIDTH="16" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
@@ -491,7 +531,7 @@ Parameters defining the aggregation algorithm.
                           otherwise it is computed by the library, using the
                           selected estimate of the spectral radius <IMG
 WIDTH="73" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
- SRC="img98.png"
+ SRC="img99.png"
 ALT="$\rho(D^{-1}A)$"> of
                           <IMG
 WIDTH="50" HEIGHT="21" ALIGN="BOTTOM" BORDER="0"
@@ -507,7 +547,7 @@ Parameters defining the aggregation algorithm.

 <P>
 <BR><P></P>
-<DIV ALIGN="CENTER"><A NAME="1313"></A>
+<DIV ALIGN="CENTER"><A NAME="1319"></A>
 <TABLE>
 <CAPTION><STRONG>Table 5:</STRONG>
 Parameters defining the coarse-space correction at the coarsest
@@ -530,21 +570,25 @@ level.</CAPTION>
 </TR>
 <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=99><code>mld_coarse_solve_</code> <BR><code>COARSE_SOLVE</code></TD>
 <TD ALIGN="LEFT"><code>character(len=*)</code></TD>
-<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=91><TT>'BJAC'</TT>   <TT>'UMF'</TT>  
+<TD ALIGN="LEFT" VALIGN="TOP" WIDTH=91><TT>'BJAC'</TT>   
+                           <TT>'UMF'</TT>   <TT>'MUMPS'</TT>  
                           <TT>'SLU'</TT>   <TT>'SLUDIST'</TT></TD>
 <TD ALIGN="LEFT"><TT>'BJAC'</TT></TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=142>Solver used at the coarsest level: block Jacobi, sequential
                           LU from UMFPACK, sequential LU from SuperLU, 
-                           distributed LU from SuperLU_Dist.
-                           <TT>'SLUDIST'</TT> requires the coarsest 
-                           matrix to be distributed, while <TT>'UMF'</TT> and
-                           <TT>'SLU'</TT> require it to be replicated.</TD>
+                           distributed LU from SuperLU_Dist or MUMPS.
+                           <TT>'SLUDIST'</TT> and <TT>'MUMPS'</TT>
+                           require the coarsest  matrix to be distributed, while
+                           <TT>'UMF'</TT> and  <TT>'SLU'</TT> require
+                           it to be replicated.</TD>
 </TR>
 <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=99><code>mld_coarse_subsolve_</code> <BR><code>COARSE_SUBSOLVE</code></TD>
 <TD ALIGN="LEFT"><code>character(len=*)</code></TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=91><TT>'ILU'</TT>   <TT>'MILU'</TT>
                             <TT>'ILUT'</TT>
-                             <TT>'UMF'</TT>   <TT>'SLU'</TT></TD>
+                             <TT>'UMF'</TT>
+                             <TT>'SLU'</TT>
+                             <TT>'MUMPS'</TT></TD>
 <TD ALIGN="LEFT">See note</TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=142>Solver for the diagonal blocks of the coarse matrix,
                           in case the block Jacobi solver
@@ -565,7 +609,7 @@ level.</CAPTION>
 <TD ALIGN="LEFT"><code>integer</code></TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=91>Any&nbsp;int.&nbsp;num.&nbsp;<IMG
 WIDTH="31" HEIGHT="31" ALIGN="MIDDLE" BORDER="0"
- SRC="img99.png"
+ SRC="img100.png"
 ALT="$&gt; 0$"></TD>
 <TD ALIGN="LEFT">4</TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=142>Number of Block-Jacobi sweeps when 'BJAC' is used as
@@ -601,9 +645,9 @@ level.</CAPTION>
 <TR><TD ALIGN="LEFT" COLSPAN=5><B>Note:</B> defaults for
  <TT>m</TT>ld_coarse_subsolve_ are chosen as</TD>
 </TR>
-<TR><TD ALIGN="LEFT" COLSPAN=5>single precision version: 'SLU' if installed, 'ILU' otherwise</TD>
+<TR><TD ALIGN="LEFT" COLSPAN=5>single precision version: 'MUMPS' if installed, 'SLU' if installed, 'ILU' otherwise</TD>
 </TR>
-<TR><TD ALIGN="LEFT" COLSPAN=5>double precision version: 'UMF' if installed,
+<TR><TD ALIGN="LEFT" COLSPAN=5>double precision version: 'MUMPS' if installed, 'UMF' if installed,
  else 'SLU' if installed, 'ILU' otherwise</TD>
 </TR>
 </TABLE>
@@ -69,14 +69,14 @@ This routine computes <!-- MATH
 -->
 <IMG
 WIDTH="118" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
- SRC="img100.png"
+ SRC="img101.png"
 ALT="$y = op(M^{-1})  x$">, where <IMG
 WIDTH="23" HEIGHT="15" ALIGN="BOTTOM" BORDER="0"
 SRC="img60.png"
 ALT="$M$"> is a previously built
 preconditioner, stored into <code>p</code>, and <IMG
 WIDTH="21" HEIGHT="31" ALIGN="MIDDLE" BORDER="0"
- SRC="img101.png"
+ SRC="img102.png"
 ALT="$op$">
 denotes the preconditioner itself or its transpose, according to
 the value of <code>trans</code>.
@@ -106,7 +106,7 @@ and hence it is completely transparent to the user.
 <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34>&nbsp;</TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>The local part of the vector <IMG
 WIDTH="15" HEIGHT="18" ALIGN="BOTTOM" BORDER="0"
- SRC="img102.png"
+ SRC="img103.png"
 ALT="$x$">. Note that <I>type</I> and   
                <I>kind_parameter</I> must be chosen according
                to the real/complex, single/double precision version of MLD2P4 under use.</TD>
@@ -117,7 +117,7 @@ and hence it is completely transparent to the user.
 <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34>&nbsp;</TD>
 <TD ALIGN="LEFT" VALIGN="TOP" WIDTH=340>The local part of the vector <IMG
 WIDTH="13" HEIGHT="31" ALIGN="MIDDLE" BORDER="0"
- SRC="img103.png"
+ SRC="img104.png"
 ALT="$y$">. Note that <I>type</I> and
                <I>kind_parameter</I> must be chosen according
                to the real/complex, single/double precision version of MLD2P4 under use.</TD>
@@ -144,28 +144,28 @@ and hence it is completely transparent to the user.
 -->
 <IMG
 WIDTH="132" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
- SRC="img104.png"
+ SRC="img105.png"
 ALT="$op(M^{-1}) = M^{-1}$">;
                if <code>trans</code> = <code>'T','t'</code> then <!-- MATH
 $op(M^{-1}) = M^{-T}$
 -->
 <IMG
 WIDTH="135" HEIGHT="40" ALIGN="MIDDLE" BORDER="0"
- SRC="img105.png"
+ SRC="img106.png"
 ALT="$op(M^{-1}) = M^{-T}$">
                (transpose of <IMG
 WIDTH="48" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
- SRC="img106.png"
+ SRC="img107.png"
 ALT="$M^{-1})$">;  if <code>trans</code> = <code>'C','c'</code> then <!-- MATH
 $op(M^{-1}) = M^{-C}$
 -->
 <IMG
 WIDTH="136" HEIGHT="40" ALIGN="MIDDLE" BORDER="0"
- SRC="img107.png"
+ SRC="img108.png"
 ALT="$op(M^{-1}) = M^{-C}$">
                (conjugate transpose of <IMG
 WIDTH="48" HEIGHT="39" ALIGN="MIDDLE" BORDER="0"
- SRC="img106.png"
+ SRC="img107.png"
 ALT="$M^{-1})$">.</TD>
 </TR>
 <TR><TD ALIGN="LEFT" VALIGN="TOP" WIDTH=34><code>work</code></TD>
@@ -63,7 +63,7 @@ Mathematics Department, Macquarie University, Sydney.
 The command line arguments were: <BR>
 <STRONG>latex2html</STRONG> <TT>-local_icons -noaddress -dir ../../html userhtml.tex</TT>
 <P>
-The translation was initiated by Salvatore Filippone on 2016-05-18
+The translation was initiated by Salvatore Filippone on 2016-05-23
 <BR><HR>

 </BODY>
@@ -63,9 +63,11 @@ according to the preconditioner type chosen by the user.
 \verb|info|   & \verb|integer, intent(out)|.\\
              & Error code. If no error, 0 is returned. See Section~\ref{sec:errors} for details.\\
 \verb|nlev|   & \verb|integer, optional, intent(in)|.\\
-              & The number of levels of the multilevel preconditioner.
-                If \verb|nlev| is not present and \verb|ptype|=\verb|'ML'|, \verb|'ml'|, 
-                then \verb|nlev|=2 is assumed. Otherwise, \verb|nlev| is ignored.\\
+              & The number of levels of the multilevel
+                preconditioner. This optional argument is deprecated,
+                new codes should set the number of levels with \verb|mld_precset|.\\
+                % If \verb|nlev| is not present and \verb|ptype|=\verb|'ML'|, \verb|'ml'|, 
+                % then \verb|nlev|=2 is assumed. Otherwise, \verb|nlev| is ignored.\\
 \end{tabular}

 \clearpage
@@ -96,7 +98,7 @@ variable of the new  type in the main program, it is possible to pass
 the new smoother/solver variable  to the setup routine as follows:
 \begin{center}
 \verb|call p%set(smoother,info [,ilev ,pos])|\\
-\verb|call p%set(solver,info [,ilev ,poss])|
+\verb|call p%set(solver,info [,ilev ,pos])|
 \end{center}
 In this way, the variable will act as a \emph{mold} to which the
 preconditioner will conform, even though the MLD2P4 library is not
@@ -133,6 +135,10 @@ modified, and thus has no direct knowledge about the new type.
 \verb|info|   & \verb|integer, intent(out)|.\\
              & Error code. If no error, 0 is returned. See Section~\ref{sec:errors}
                for details.\\
+\verb|pos|   & \verb|charater(len=*), intent(in)|.\\
+              & Whether the other arguments apply to the \verb|'PRE'|
+                or to the \verb|'POST'| smoothers.\\
+
 %
 %\verb|ilev|   & \verb|integer, optional, intent(in)|.\\
 %              & For the multilevel preconditioner, the level at which the
@@ -297,19 +303,43 @@ according to their needs.
 %\multicolumn{5}{|c|}{\emph{aggregation algorithm}} \\ \hline
 \verb|mld_coarse_aggr_size_|  \break \verb|COARSE_AGGR_SIZE| & \verb|integer|
                         & A positive number
-                         & 0, meaning that the size is fixed at
-                         \verb|precinit| time
-                         & Coarse size threshold. Disregard the
-                         original specification of number of levels in
-                         \verb|precinit| and continue aggregation
-                         until either the global number of variables
-                         is below this threshold, or the aggregation
-                         does not reduce the size any longer. \\ \hline 
+                         &  The  cubic root of 
+                           the matrix size at the fine level.
+                         & Coarse size threshold. Aggregation will
+                           proceed  until either the global number of
+                           variables is below this threshold, or the
+                           aggregation  does not reduce the size any
+                           longer, or the maximum number of levels is
+                           reached.  \\ \hline  
+\verb|mld_min_aggr_ratio|  \break \verb|MIN_AGGR_RATIO| & \verb|real|
+                         & A number greater than one
+                         & 1.5
+                         & Minimum aggregation ratio. Aggregation will
+                           stop if the ratio between the matrix sizes
+                           at two consecutive levels drops below this
+                           threshold.\\ \hline   
+\verb|mld_n_prec_levs_|  \break \verb|N_PREC_LEVS| & \verb|integer|
+                         & A number greater than 1, or -1.
+                         & -1
+                         & Number of levels; if set to a positive
+                           number greater than 1, it will force the
+                           aggregation algorithm to use this many
+                           levels (unless there is no reduction in the
+                           coarse matrix size). \\ \hline  
+\verb|mld_max_prec_levs_|  \break \verb|MAX_PREC_LEVS| & \verb|integer|
+                         & A positive number
+                         & 20
+                         & Maximum number of levels: irrespective of
+                           the other settings, do not use more than
+                           this many levels. \\ \hline  
 \verb|mld_aggr_alg_|  \break \verb|AGGR_ALG|  & \verb|character(len=*)|
-                         & \texttt{'DEC'}
+                         & \texttt{'DEC'}, \texttt{'SYMDEC'}
                         & \texttt{'DEC'}
                         & Aggregation algorithm. Currently, only the
-                         decoupled aggregation is available. \\ \hline 
+                         decoupled aggregation is available; the
+                           \verb|SYMDEC| option  applies decoupled
+                           aggregation to  the sparsity pattern
+                           of $A+A^T$.\\ \hline 
 \verb|mld_aggr_ord_|  \break \verb|AGGR_ORD|  & \verb|character(len=*)|
                         & \texttt{'NATURAL'}
                         & \texttt{'DEGREE'}
@@ -331,15 +361,15 @@ according to their needs.
                         & Any~real~num. $\in [0, 1]$
                         & 1.0
                         & Scale factor applied to the threshold going
- from level $ilev$ to level $ilev+1$. \\ \hline
+                           from level $ilev$ to level $ilev+1$. \\ \hline
 \verb|mld_aggr_omega_alg_|  \break \verb|AGGR_OMEGA_ALG|& \verb|character(len=*)|
                         & \texttt{'EIG\_EST'} \hspace{2.5cm} \texttt{'USER\_CHOICE'}
                         & \texttt{'EIG\_EST'}
                         & How the damping parameter $\omega$ in the
-                         smoothed aggregation should be computed:
-                         either via an estimate of the spectral radius of
-                         $D^{-1}A$, or explicily
-                         specified by the user. \\ \hline
+                           smoothed aggregation should be computed:
+                           either via an estimate of the spectral radius of
+                           $D^{-1}A$, or explicily
+                           specified by the user. \\ \hline
 \verb|mld_aggr_eig_|  \break \verb|AGGR_EIG|    & \verb|character(len=*)|
                         & \texttt{'A\_NORMI'}
                         & \texttt{'A\_NORMI'}
@@ -376,19 +406,23 @@ according to their needs.
                         & Coarsest matrix: distributed among the processors or
                           replicated on each of them. \\ \hline
 \verb|mld_coarse_solve_| \break \verb|COARSE_SOLVE| & \verb|character(len=*)|
-                         & \texttt{'BJAC'} \hspace{2.5cm} \texttt{'UMF'} \hspace{2.5cm}
+                         & \texttt{'BJAC'} \hspace{2.5cm} 
+                           \texttt{'UMF'} \hspace{2.5cm} \texttt{'MUMPS'} \hspace{2.5cm}
                           \texttt{'SLU'} \hspace{2.5cm} \texttt{'SLUDIST'}
                         & \texttt{'BJAC'}
                         & Solver used at the coarsest level: block Jacobi, sequential
                           LU from UMFPACK, sequential LU from SuperLU, 
-                           distributed LU from SuperLU\_Dist.
-                           \texttt{'SLUDIST'} requires the coarsest 
-                           matrix to be distributed, while \texttt{'UMF'} and
-                           \texttt{'SLU'} require it to be replicated. \\ \hline
+                           distributed LU from SuperLU\_Dist or MUMPS.
+                           \texttt{'SLUDIST'} and \texttt{'MUMPS'}
+                           require the coarsest  matrix to be distributed, while
+                           \texttt{'UMF'} and  \texttt{'SLU'} require
+                           it to be replicated. \\ \hline 
 \verb|mld_coarse_subsolve_| \break \verb|COARSE_SUBSOLVE| & \verb|character(len=*)|
                         & \texttt{'ILU'} \hspace{2.5cm} \texttt{'MILU'}
                           \hspace{2.5cm} \texttt{'ILUT'}
-                           \hspace{2.5cm} \texttt{'UMF'} \hspace{2.5cm} \texttt{'SLU'}
+                           \hspace{2.5cm} \texttt{'UMF'}
+                           \hspace{2.5cm} \texttt{'SLU'}
+                           \hspace{2.5cm} \texttt{'MUMPS'}
                         & See note
                         & Solver for the diagonal blocks of the coarse matrix,
                           in case the block Jacobi solver
@@ -411,8 +445,8 @@ according to their needs.
 \hline
 \multicolumn{5}{|l|}{{\bfseries Note:} defaults for
  {\texttt mld\_coarse\_subsolve\_} are chosen as }\\ 
-\multicolumn{5}{|l|}{single precision version: 'SLU' if installed, 'ILU' otherwise}\\
-\multicolumn{5}{|l|}{double precision version: 'UMF' if installed,
+\multicolumn{5}{|l|}{single precision version: 'MUMPS' if installed, 'SLU' if installed, 'ILU' otherwise}\\
+\multicolumn{5}{|l|}{double precision version: 'MUMPS' if installed, 'UMF' if installed,
  else 'SLU' if installed, 'ILU' otherwise}\\
 \hline
 \end{tabular}
@@ -1,6 +1,6 @@
 BICGSTAB                    ! Iterative method: BiCGSTAB BiCG CGS RGMRES BiCGSTABL CG
 CSR                         ! Storage format CSR COO JAD 
-0100                        ! IDIM; domain size is idim**3
+0030                        ! IDIM; domain size is idim**3
 2                           ! ISTOPC
 2000                        ! ITMAX
 10                          ! ITRACE
@@ -17,7 +17,7 @@ GS                          ! Subdomain solver DSCALE ILU MILU ILUT UMF SLU GS M
 1.d-4                       ! Threshold T for ILU(T,P) 
 4                           ! Smoother/Jacobi  sweeps 
 BJAC                        ! Smoother type  JACOBI BJAC AS; ignored for non-ML
-2                           ! Number of levels in a multilevel preconditioner
+3                           ! Number of levels in a multilevel preconditioner
 SMOOTHED                    ! Kind of aggregation: SMOOTHED, NONSMOOTHED, MINENERGY
 SYMDEC                      ! Type of aggregation DEC SYMDEC 
 NATURAL                     ! Ordering of aggregation NATURAL DEGREE
@@ -30,4 +30,4 @@ ILU                         ! Coarse level: subsolver DSCALE GS ILU UMF SLU  SLU
 1.d-4                       ! Coarse level: Threshold T for ILU(T,P) 
 4                           ! Coarse level: Number of Jacobi sweeps 
 -0.10d0                     ! Smoother Aggregation Threshold: >= 0.0 default if <0
-1000                        ! Coarse size limit to determine levels. If <0, then use NL
+-010                        ! Coarse size limit to determine levels. If <0, then use NL