This directory contains  the PSBLAS library, version 2.2

 
Version 1.0 of the library was described in:
S. Filippone, M. Colajanni
PSBLAS: A library for parallel linear algebra computation on sparse matrices
ACM Trans. on Math. Software, 26(4), Dec. 2000, pp. 527-550.

PLATFORMS: 

The compilation process relies on the choice of an appropriate
Make.inc file; we have tested with AIX XLF, Intel ifort/Linux,  Nag
f95/Linux, GNU Fortran/Linux, Sun Forte 6.2. If you succeed in
compiling with  other compiler/operating systems please let us know. 


LINUX:

On Linux we work with the GCC compiler; note that we require version
4.2.0 (or later) as it contains support for ALLOCATABLEs (as
specified  in TR15581). 

For the Intel compilers, we recommend version 9.1 or later.

IBM SP.
The library has been tested on an IBM SP5, with XLC and XLF 
version 10.1 and the IBM ESSL/PESSL versions of the BLAS and the
BLACS. 
The  setting 
F90=xlf95 -qsuffix=f=f90:cpp=F90
in Make.inc.sp5 takes care of the f90/F90 extensions. 


UTILITIES
The test/util directory contains some utilities to convert to/from
Harwell-Boeing and MatrixMarket file formats. 


DOCUMENTATION

See userguide.pdf 
Please consult the sample programs, especially test/pargen/ppde.f90. 


OTHER SOFTWARE CREDITS 

We include our modified implementation of some of the Sparker (serial
sparse BLAS)  material,  e.g. Jagged diagonal, plus a number of
extensions of our own design. The original file spblas.f can be
downloaded from matisa.cc.rl.ac.uk; of course any bugs in our
implementation are our own to fix.  The main reference for the serial
sparse BLAS is: 
Duff, I., Marrone, M., Radicati, G., and Vittoli, C.
Level 3 basic linear algebra subprograms for sparse matrices: a user 
level interface
ACM Trans. Math. Softw., 23(3), 379-401, 1997.

In the multilevel preconditioners we use SMMP by Randolph E. Bank and
Craig C. Douglas  na.bank@na-net.ornl.gov and
na.cdouglas@na-net.ornl.gov;  we wrapped  it in a Fortran 95 interface
with dynamic memory allocation. 

INSTALLING

To compile and run our software you will need the following
prerequisites (see also SERIAL below):

1. A working version of MPI

2. The MPI version of the BLACS; some systems (e.g. IBM SP) provide
   a specific version, otherwise you can find it at
   http://www.netlib.org/blacs/index.html 

3. A version of the BLAS; if you don't have a specific version for
   your platform you may try ATLAS available from
   http://math-atlas.sourceforge.net/ 

4. We have had good results with  the METIS library, from 
   http://www-users.cs.umn.edu/~karypis/metis/metis/main.html 
   This is optional; it is  used in the util and test/fileread
   directories but only if you define the HAVE_METIS directive.

We offer an experimental configure script: if everything works well,
it will generate a Make.inc file suitable for building the library. 
The script is capable of recognizing the needed libraries with their
default names; if they are in unusual places consider adding the paths
with --with-lib, or explicitly specifying the names in --with-blas,
--with-blacs etc. 
Please note that a common way for the configure script to fail is to
specify inconsistent MPI vs. plain compilers, either directly or
indirectly via environment variables; e.g. specifying the Intel
compiler with FC=ifort and the default MPIFC=mpif90 which points to
GNU Fortran 4.1. The best way to avoid this situation is (in our
opinion) to use the environment modules package (see
http://modules.sourceforge.net/), and load the relevant variables with
(e.g.)  
module load gnu42 mpich 
This will delegate to the modules setup to make sure that the version
of mpich in use is the one compiled with the gnu42 compilers. 
After the configure script has completed you can always tweak the
Make.inc  file yourself. 

An annoying problem exists with some versions of MPICH: the configure
script will set -DMPI_MOD, which is to say, the MPI call interfaces
will be resolved by using the MPI Fortran module. However usage of the
module may cause compilation to fail if coupled with the debugging
option -ggdb, because the compiler complains that it cannot find any
matching interface. 
The solution: either take out the -ggdb option, or, if you really need
to debug, force -DMPI_H in place of -DMPI_MOD.


As a backup alternative, you can always choose a Make.inc.XXX file in
directory Make that fits your compilers, modify the paths to libraries
to  match your installation and copy it to Make.inc in the top
directory. 

After you have Make.inc fixed,  run 
 make 
to  compile the library; go to the test directory and its
subdirectories to get test programs done.   
If you specify --prefix=/path you can do make install and the
libraries will be installed under /path/lib, while the module files
will be installed under /path/include.


KNOWN ISSUES.

An annoying problem exists with some versions of MPI: if the configure
script sets -DMPI_MOD the MPI call interfaces will be resolved by
using the MPI Fortran module. 
However usage of the  module may cause compilation to fail when
coupled with the debugging option -g, because the compiler complains
that it cannot find a matching interface for some of the
communication routines.
The solution: either take out the -g option, or, if you really need to
debug, force -DMPI_H in place of -DMPI_MOD. 




SERIAL: We now provide an (experimental) option to run in serial
	mode. This has only been tested with GCC but it should work
	with the others as well. In serial mode you don't need the
	prereqs 1 and 2 above, and you need to use the -serialmpi
	Make.inc. BEWARE: we only provide a VERY minimal set of fake mpi
	routines that is known to work with our codes; specifically, we
	do not handle a process doing send/receives to itself, neither
	do we handle user defined data types. 

TODO:
Fix all reamining bugs. Bugs? We dont' have any ! ;-)
Work on a single precision version if there is sufficient demand for
it.

The PSBLAS team. 


Contact: Salvatore Filippone     salvatore.filippone@uniroma2.it

Credits for version 2.2:
Michele Martone contributed the configure machinery. 

Credits for version 2.0:
Salvatore  Filippone
Alfredo    Buttari


In a sister package called MLD2P4 we are going to provide a library of
more sophisticated preconditioners, including parallel multilevel ones
that were  developed with the contribution of:  
Pasqua     D'Ambra
Daniela    di Serafino

In that package we will provide interfaces to the following software
packages: 
   --  SuperLU 3.0        http://crd.lbl.gov/~xiaoye/SuperLU/
   --  UMFPACK 4.4        http://www.cise.ufl.edu/research/sparse/umfpack/ 
These are optional, you only need to install them if you actually want
to use them.  
The MLD2P4 package will be published soon, watch this space!. 

Credits for version 1.0:

Salvatore  Filippone
Michele    Colajanni
Fabio      Cerioni
Stefano    Maiolatesi
Dario      Pascucci