===================== ScaLAPACK README FILE

VERSION 1.0 : February 28, 1995

VERSION 1.1 : March 20, 1995

VERSION 1.2 : May 10, 1996

VERSION 1.3 : June 5, 1996

VERSION 1.4 : November 17, 1996

VERSION 1.5 : May 1, 1997

VERSION 1.6 : November 15, 1997

VERSION 1.7 : August, 2001

VERSION 1.8 : April 2007

VERSION 2.0 : November, 2011 VERSION 2.0.1 : January, 2012 VERSION 2.0.2 : May, 2012

VERSION 2.1 : Nov, 2019

VERSION 2.2 : Feb 2022

ScaLAPACK, or Scalable LAPACK, is a library of high performance linear algebra routines for distributed memory computers supporting MPI.

The complete ScaLAPACK package is freely available on netlib and can be obtained via the World Wide Web or anonymous ftp.

http://www.netlib.org/scalapack/

=============== GitHub Repository ================

https://github.com/Reference-ScaLAPACK/scalapack/

==================================================

ScaLAPACK, version 2.0, includes routines for the solution of dense, band, and tridiagonal linear systems of equations, condition estimation and iterative refinement, for LU and Cholesky factorization, matrix inversion, full-rank linear least squares problems, orthogonal and generalized orthogonal factorizations, orthogonal transformation routines, reductions to upper Hessenberg, bidiagonal and tridiagonal form, reduction of a symmetric-definite/ Hermitian-definite generalized eigenproblem to standard form, the symmetric/Hermitian, divide-and-conquer symmetric/Hermitian, generalized symmetric/Hermitian and the nonsymmetric eigenproblem, and the singular value decomposition. With the exception of the singular value decomposition, most routines are available in four types: single precision real, double precision real, single precision complex, and double precision complex.

New in version 2.0:

• ScaLAPACK now only supports MPI.

• The BLACS is now part of ScaLAPACK, and is compiled into the ScaLAPACK library. It is no longer necessary to link against BLACS libraries.

• Building ScaLAPACK using cmake is now supported.

• New MRRR Symmetric Eigenvalue Problem routines are included: pssyevr, pdsyevr, pcheevr and pzheevr.

• New Nonsymmetric Eigenvalue Problem QR routines for computing eigenvalues of a Hessenberg matrix are included for real matrices:
  pshseqr and pdhseqr.

Unless otherwise noted, the current scalapack.tgz on netlib contains all available updates.

Errata for ScaLAPACK (source code and documentation) can be found at:

http://www.netlib.org/scalapack/errata.html

ScaLAPACK example programs can be found at:

http://www.netlib.org/scalapack/examples/

A basic example is included in the EXAMPLE directory.

The ScaLAPACK User's Guide for ScaLAPACK version 1.5 is available from SIAM at:

http://www.ec-securehost.com/SIAM/SE04.html

To view an HTML version of the Users' Guide for version 1.5, see:

http://www.netlib.org/scalapack/slug/

A number of technical reports were written during the development of ScaLAPACK and published as LAPACK Working Notes by the University of Tennessee. These working notes are available at:

http://www.netlib.org/lapack/lawns/

All questions/comments should be directed to [email protected].

The Makefiles in ScaLAPACK and its support libraries assume the basic directory structure below:

                           SCALAPACK/

/ | _________ / | | | <library.a> | SLmake.inc | | |
| | | | | | | | | | | | | | BLACS/ EXAMPLE/ PBLAS/ REDIST/ SRC/ TESTING/ TOOLS/ / Input \
/ Files &
/Executables\

NOTE: It is assumed that the BLAS and LAPACK libraries (and MPI) are available on your machine. These libraries are NOT included with this distribution, and may be obtained at the sites below.

   http://www.netlib.org/blas/
   http://www.netlib.org/lapack/
   http://www.mcs.anl.gov/mpi/mpich/
   http://www.lam-mpi.org/
   http://www.open-mpi.org/

All ScaLAPACK routines -- driver, computational, and auxiliary -- can be found in the SRC/ directory. Testing routines and input files can be found in the TESTING/ directory. All machine-specific parameters and the locations of BLAS and LAPACK libraries are specified in the SCALAPACK/SLmake.inc file. This include file is then referenced in all subdirectory Makefiles. Once the include file has been modified, the entire installation process (including the building of testing executables) can be performed by typing ``make'' in the top-level ScaLAPACK directory.

ScaLAPACK uses the default (typically 4-byte) integers. With compilers that support it, the library can be compiled with long (8-byte) integers instead. This can be achived by providing the flag "-DInt=long" to the C compiler (or with another corresponding C type) and, simultaneously, the appropriate integer promotion flag (e.g. "-fdefault-integer-8" or "-i8") to the Fortran compiler. It is expected that the BLAS/LAPACK library linked to ScaLAPACK uses the 8-byte integers as well. Note that in order to run the test suite with long integers, it is necessary to replace the hardcoded byte sizes in the tests before the compilation using

sed -i 's/INTSZ = 4/INTSZ = 8/g'   TESTING/EIG/* TESTING/LIN/*
sed -i 's/INTGSZ = 4/INTGSZ = 8/g' TESTING/EIG/* TESTING/LIN/*

Even then, the tests "xssep", "xsgsep" and "xssyevr" will fail, because they are already written with the assumption that an integer fits into memory occupied by a real number, which is mostly not true for combination of default Fortran real numbers and long integers.

ScaLAPACK Library Versioning

From v2.2.1, the ScaLAPACK library is generated with a versioned name (i.e. with a shared library ABI soname) according to the following pattern:

• We assume that the ABI updates with each MINOR release.
• An API update (and therefore an ABI update) will be expected with any MAJOR release.
• No ABI update should occur between PATCH releases.

Hence with the full version in triplet form as MAJOR.MINOR.PATCH, the shared library soname will be libscalapack.so.MAJOR.MINOR.