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95 lines
3.6 KiB
Plaintext
95 lines
3.6 KiB
Plaintext
This directory contains the MLD2P4 set of preconditioners, version 2.1
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WHAT'S NEW
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Version 2.1
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1. The multigrid preconditioner now include fully general V- and W-
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cycles. We also support K-cycles, intended to be used in
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conjunction with Flexible CG available in PSBLAS 3.5.
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2. The smoothers now include popular
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variants such as Jacobi, forward and backward hybrid
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Gauss-Seidel (intra-process Gauss-Seidel, inter-process
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block-Jacobi).
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3. The PRE and POST specification for smoothers can now be
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specified independently of each other: you can even specify
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different smoothers for PRE and POST (e.g. forward Gauss-Seidel
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PRE with backward Gauss-Seidel POST). The default is to
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have the specs apply to both PRE and POST.
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Version 2.0.
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Finally moved to F2003, with the support of PSBLAS3.
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There are a few minor differences at user level:
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1. In the configure step, you should specify the INSTALL directory
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of PSBLAS version 3.4, not the source directory;
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2. In the various makefiles, libmld_prec.a should now be used in
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addition (and in front of) libpsb_prec.a, and no longer in
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place of it.
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3. As for the basic usage, this is practically identical to the
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previous version(s).
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You should use the same MPI/serial compilers that were used for the
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PSBLAS installation.
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The Fortran 2003 support means that it is far easier to develop and
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integrate new solvers and smoothers; you need to take one of the
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existing solvers/smoothers as a model, develop your own by
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changing/replacing the model contents, and then pass the new object
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to the PREC%SET() method which will copy into the internals, as per
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the PROTOTYPE design pattern. Take a look at the test/newslv
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directory to see an example. It's easier done than said!
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Versions known to work:
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UMFPACK: 5.4
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SuperLU: 4.3 and 5.0
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SuperLU_Dist: 3.3 and 4.2
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Note that with SuperLU_Dist you will probably need to add further
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link options, e.g. the ParMetis library or the openmp runtime;
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you can do this using the configure option --with-extra-libs
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In version 1.1:
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- The MLD_SIZEOF() function has been redefined to be INTEGER(8), so
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as to be able to measure large data sets.
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- The internals of the multilevel preconditioner have been repackaged
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in a more structured fashion; no changes are needed in the user
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code.
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- Note that we now need version 2.3.1 of PSBLAS.
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TO COMPILE
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0. Unpack the tar file in a directory of your choice (preferrably
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outside the main PSBLAS directory).
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1. run configure --with-psblas=<ABSOLUTE path of the PSBLAS install directory>
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adding the options for SuperLU, SuperLU_Dist, UMFPACK as desired.
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See MLD2P4 User's and Reference Guide (Section 3) for details.
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2. Tweak Make.inc if you are not satisfied.
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3. make;
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4. Go into the test subdirectory and build the examples of your choice.
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NOTES
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- The single precision version is supported only by SuperLU; thus, even
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if you specify at configure to use UMFPACK or SuperLU_Dist, the
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corresponding preconditioner options will be available only from the
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double precision version.
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- A program that was using the PSBLAS precoditioners needs no source
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code changes, but should be recompiled. If the new preconditioner
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(or preconditioner options, such as ILU(N) factorization) are
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required, only the type of the preconditioner object and its
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setup/build/free calls should be updated; the rest of the
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application continues to make use of the PSBLAS existing
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interfaces.
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CREDITS
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developed by
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Salvatore Filippone
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Pasqua D'Ambra
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Daniela di Serafino
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Alfredo Buttari
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