PETSc Debian Package Description -------------------------------- INTRODUCTION This source package is distributed in five binary packages: the shared libraries are in libpetsc-real3.18; header files, static libraries and important files for building examples are in libpetsc-real3.18-dev, this also sets up various alternatives links; debugging libraries are in libpetsc-real3.18-dbg; extensive documentation and source code from "tests" and "tutorials" directories are in petsc3.18-doc. Standard packages are configured for real numbers. Complex numbers are configured in the libpetsc-complex* packages. The preferred default configuration may be set using alternatives (petsc and libpetsc.so.3.18). The preferred PETSc installation is located at /usr/lib/petsc. This is a symlink to the actual installation, managed by Debian alternatives (see below). The standard installation is located at /usr/lib/petscdir/petsc/-real e.g. /usr/lib/petscdir/petsc3.18/x86_64-linux-gnu-real Preferred minor patch versions of each major version (e.g. 3.18) are linked via /usr/lib/petscdir/3.18 (also, preferred versions of 3.18-real and 3.18-complex). These links are controlled by alternatives. libpetsc.so is also controlled by alternatives (libpetsc.so.3.18) With libpetsc3.18-dev installed, you can build programs against it two ways: 1. Standard build convention: use -I/usr/include/petsc for headers and link to optimized libraries in /usr/lib, so your resulting binaries will only depend on libpetsc3.18.0. 2. PETSc build convention: adapt a makefile from one of their tests or tutorial directories and build with make PETSC_DIR=/usr/lib/petsc 3. Use pkg-config (via /usr/lib//pkgconfig/PETSC.pc). Of these, the latter two are probably easier, as they automatically set up all of the include paths and library linkages for PETSc and its various dependencies. EXAMPLES For your testing convenience, petsc3.18-doc comes with the source code of the full PETSc test and tutorial suite. Just do: tar xzf /usr/share/doc/petsc3.18-doc/src.tar.gz then cd src, and use the PETSc build convention make command above with target testexamples or testfortran (add _uni to the target name for single-processor operation). This will build and run the entire suite. Then choose an appropriate example to modify for your own purposes, and you're off. NOTE: not all of the examples work! If one fails for you, please try to patch it to make it work; you can often use a similar example in the same directory to do this. You may be able to get some help from the upstream maintainers for this, see the homepage for details, but the examples do not seem to be consistently maintained. If you file a bug report because of a failed example, I will forward it upstream and leave it open until it's fixed, but can't promise I'll try to fix it. DEBUGGING LIBRARY With libpetsc-real3.18-dbg installed, a debug version is available at /usr/lib/petscdir/petsc3.18/x86_64-linux-gnu-real-debug This library includes unstripped symbols and also has internal PETSc debugging switched on. It may be accessed 1) by setting PETSC_DIR 2) via the pkg-config file in /usr/lib/petscdir/petsc3.18/x86_64-linux-gnu-real-debug/lib/pkgconfig 3) or by configuring as preferred alternative with update-alternatives. REPORTING BUGS and BUILDING FROM SOURCE Also, upstream does not maintain old versions of PETSc. If you have trouble with the version in stable, you should file a bug report (see http://bugs.debian.org/ for directions), then try building the version in unstable, by adding an unstable source code line to /etc/apt/sources.list, then typing (as a normal user): fakeroot apt-get --compile source petsc This will download and build everything for you. If the unstable version does not solve your problem, or the customizations below don't meet your needs, file a bug report, and if your problem is not specific to the Debian package then I'll forward it upstream. CUSTOMIZING THE DEBIAN PETSC PACKAGE There are several ways to customize this package: 1) To use a different PETSC_ARCH variable (e.g. linux_alpha_dec to use the Compaq compilers on an Alpha), do: apt-get source petsc cd petsc-3.18.0.dsfg1 fakeroot debian/rules PETSC_ARCH=linux_alpha_dec binary Note that this will only build architecture-dependent packages, and with different package names, different directory names (still linked from /usr/lib/petsc), and different shared library sonames. 2) You can also build the libraries to use the lam or mpich MPI implementation instead of the default openmpi by setting PETSC_MPI=lam (or mpich) and PETSC_MPI_DIR=/usr/lib/lam (or mpich, or mpich-mpd or mpich-shmem) and build as with the Compaq compilers above. This will also result in only architecture-dependent packages with different package names, directory names, and shared library sonames. If needed, you can change the soname of your custom library by using the configure flag --shared-library-extension=, which changes the library and soname to libpetsc.so Note that individual users can build against non-default installed versions of PETSc simply by setting the PETSC_DIR environment variable to the target directory instead of /usr/lib/petsc, for example to build against the lam version a user might set PETSC_DIR=/usr/lib/petscdir/petsc3.18/x86_64-linux-gnu-lam-real . NOTE ON SYMBOLIC LINKS THROUGH /etc/alternatives Because it is possible and often desirable to have multiple versions of PETSc installed at the same time, this package facilitates the process by setting up multiple symbolic links through /etc/alternatives. To switch the default symbolic links from one installed version to another, you should use the update-alternatives Debian script (in /usr/sbin). For example: update-alternatives --display petsc will show you the current symlink from /usr/lib/petsc, and all of its accompanying "slave" links, as well as all of the other possible values of links if you have multiple versions of PETSc installed. The command: update-alternatives --config petsc (as root) will present you with a list of possible values to choose from, if there is more than one. When setting your preference for /usr/lib/petsc via "update-alternatives --config petsc", it is important for consistency to also update your preference for the main shared library files provided by libpetsc-real3.18 or libpetsc-complex3.18. These alternative links are controlled by libpetsc.so.3.18: update-alternatives --config libpetsc.so.3.18 The preferred alternative for the major petsc version (e.g. 3.18) is linked in /usr/lib/petscdir/3.18 and set by update-alternatives --config petsc3.18 To maintain the consistency of the master and slave symlinks, it is very important that you use the Debian update-alternatives command, and do NOT hand-edit the symbolic links yourself. The full set of PETSc alternatives is: petsc - set the default version (real or complex) of PETSc (/usr/lib/petsc) libpetsc_real.so - set the default PETSc shared library with real number support libpetsc_complex.so - set the default PETSc shared library with complex number support petsc3.18 - set the preferred version (real or complex, or debug) of PETSc 3.18 (/usr/lib/petscdir/3.18) libpetsc.so.3.18 - set the preferred version (real or complex) for the shared library of PETSc 3.18 ===== 64-bit indexing ===== Support for 64-bit indexing is provided in libpetsc64* packages. These enables PETSc to be used on larger systems with more than 2 billion elements. Suitesparse does not support 64-bit indexing on 32-bit platforms (armel armhf i386 powerpc x32) and Suitesparse support has therefore been dropped from the 64-bit builds on these architectures. -- Drew Parsons , Sat, 20 June 2020 10:00:00 +0800