Configuring PETSc#

Important

Obtain PETSc via the repository or download the latest tarball: download documentation.

See quick-start tutorial for a step-by-step walk-through of the installation process.

Common Example Usages#

Attention

There are many example configure scripts at config/examples/*.py. These cover a wide variety of systems, and we use some of these scripts locally for testing. One can modify these files and run them in lieu of writing one yourself. For example:

$ ./config/examples/arch-ci-osx-dbg.py

If there is a system for which we do not yet have such a configure script and/or the script in the examples directory is outdated we welcome your feedback by submitting your recommendations to petsc-maint@mcs.anl.gov. See bug report documentation for more information.

  • If you do not have a Fortran compiler or MPICH installed locally (and want to use PETSc from C only).

    $ ./configure --with-cc=gcc --with-cxx=0 --with-fc=0 --download-f2cblaslapack --download-mpich

  • Same as above - but install in a user specified (prefix) location.

    $ ./configure --prefix=/home/user/soft/petsc-install --with-cc=gcc --with-cxx=0 --with-fc=0 --download-f2cblaslapack --download-mpich

  • If BLAS/LAPACK, MPI sources (in “-devel” packages in most Linux distributions) are already installed in default system/compiler locations and mpicc, mpif90, mpiexec are available via $PATH - configure does not require any additional options.

    $ ./configure

  • If BLAS/LAPACK, MPI are already installed in known user location use:

    $ ./configure --with-blaslapack-dir=/usr/local/blaslapack --with-mpi-dir=/usr/local/mpich

    or

    $ ./configure --with-blaslapack-dir=/usr/local/blaslapack --with-cc=/usr/local/mpich/bin/mpicc --with-mpi-f90=/usr/local/mpich/bin/mpif90 --with-mpiexec=/usr/local/mpich/bin/mpiexec

Note

Do not specify --with-cc, --with-fc etc for the above when using --with-mpi-dir - so that mpicc/ mpif90 will be picked up from mpi-dir!

  • Build Complex version of PETSc (using c++ compiler):

    $ ./configure --with-cc=gcc --with-fc=gfortran --with-cxx=g++ --with-clanguage=cxx --download-fblaslapack --download-mpich --with-scalar-type=complex

  • Install 2 variants of PETSc, one with gnu, the other with Intel compilers. Specify different $PETSC_ARCH for each build. See multiple PETSc install documentation for further recommendations:

    $ ./configure PETSC_ARCH=linux-gnu --with-cc=gcc --with-cxx=g++ --with-fc=gfortran --download-mpich
$ make PETSC_ARCH=linux-gnu all test
$ ./configure PETSC_ARCH=linux-gnu-intel --with-cc=icc --with-cxx=icpc --with-fc=ifort --download-mpich --with-blaslapack-dir=/usr/local/mkl
$ make PETSC_ARCH=linux-gnu-intel all test

Compilers#

Important

If no compilers are specified - configure will automatically look for available MPI or regular compilers in the user’s $PATH in the following order:

  1. mpicc/mpicxx/mpif90

  2. gcc/g++/gfortran

  3. cc/CC etc..

  • Specify compilers using the options --with-cc/--with-cxx/--with-fc for c, c++, and fortran compilers respectively:

    $ ./configure --with-cc=gcc --with-cxx=g++ --with-fc=gfortran

Important

It’s best to use MPI compiler wrappers 1. This can be done by either specifying --with-cc=mpicc or --with-mpi-dir (and not --with-cc=gcc)

$ ./configure --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90

or the following (but without --with-cc=gcc)

$ ./configure --with-mpi-dir=/opt/mpich2-1.1

See MPI for details on how to select specific MPI compiler wrappers or the specific compiler used by the MPI compiler wrapper.

  • If a Fortran compiler is not available or not needed - disable using:

    $ ./configure --with-fc=0

  • If a c++ compiler is not available or not needed - disable using:

    $ ./configure --with-cxx=0

configure defaults to building PETSc in debug mode. One can switch to optimized mode with the configure option --with-debugging=0 (we suggest using a different $PETSC_ARCH for debug and optimized builds, for example arch-debug and arch-opt, this way you can switch between debugging your code and running for performance by simply changing the value of $PETSC_ARCH). See multiple install documentation for further details.

Additionally one can specify more suitable optimization flags with the options COPTFLAGS, FOPTFLAGS, CXXOPTFLAGS. For example when using gnu compilers with corresponding optimization flags:

$ ./configure --with-cc=gcc --with-cxx=g++ --with-fc=gfortran --with-debugging=0 COPTFLAGS='-O3 -march=native -mtune=native' CXXOPTFLAGS='-O3 -march=native -mtune=native' FOPTFLAGS='-O3 -march=native -mtune=native' --download-mpich

Warning

configure cannot detect compiler libraries for certain set of compilers. In this case one can specify additional system/compiler libraries using the LIBS option:

$ ./configure --LIBS='-ldl /usr/lib/libm.a'

External Packages#

Note

BLAS/LAPACK is the only required external package (other than of course build tools such as compilers and make). PETSc may be built and run without MPI support if processing only in serial.

For any external packages used with PETSc we highly recommend you have PETSc download and install the packages, rather than you installing them separately first. This insures that:

  • The packages are installed with the same compilers and compiler options as PETSc so that they can work together.

  • A compatible version of the package is installed. A generic install of this package might not be compatible with PETSc (perhaps due to version differences - or perhaps due to the requirement of additional patches for it to work with PETSc).

  • Some packages have bug fixes, portability patches, and upgrades for dependent packages that have not yet been included in an upstream release, and hence may not play nice with PETSc.

PETSc provides interfaces to various external packages. One can optionally use external solvers like HYPRE, MUMPS, and others from within PETSc applications.

PETSc configure has the ability to download and install these external packages. Alternatively if these packages are already installed, then configure can detect and use them.

If you are behind a firewall and cannot use a proxy for the downloads or have a very slow network, use the additional option --with-packages-download-dir=/path/to/dir. This will trigger configure to print the URLs of all the packages you must download. You may then download the packages to some directory (do not uncompress or untar the files) and then point configure to these copies of the packages instead of trying to download them directly from the internet.

The following modes can be used to download/install external packages with configure.

  • --download-PACKAGENAME: Download specified package and install it, enabling PETSc to use this package. This is the recommended method to couple any external packages with PETSc:

    $ ./configure --download-fblaslapack --download-mpich

  • --download-PACKAGENAME=/path/to/PACKAGENAME.tar.gz: If configure cannot automatically download the package (due to network/firewall issues), one can download the package by alternative means (perhaps wget, curl, or scp via some other machine). Once the tarfile is downloaded, the path to this file can be specified to configure with this option. configure will proceed to install this package and then configure PETSc with it:

    $ ./configure --download-mpich=/home/petsc/mpich2-1.0.4p1.tar.gz

  • --with-PACKAGENAME-dir=/path/to/dir: If the external package is already installed - specify its location to configure (it will attempt to detect and include relevant library files from this location). Normally this corresponds to the top-level installation directory for the package:

    $ ./configure --with-mpi-dir=/home/petsc/software/mpich2-1.0.4p1

  • --with-PACKAGENAME-include=/path/to/include/dir and --with-PACKAGENAME-lib=LIBRARYLIST: Usually a package is defined completely by its include file location and library list. If the package is already installed one can use these two options to specify the package to configure. For example:

    $ ./configure --with-superlu-include=/home/petsc/software/superlu/include --with-superlu-lib=/home/petsc/software/superlu/lib/libsuperlu.a

    or

    $ ./configure --with-parmetis-include=/sandbox/balay/parmetis/include --with-parmetis-lib="-L/sandbox/balay/parmetis/lib -lparmetis -lmetis"

    or

    $ ./configure --with-parmetis-include=/sandbox/balay/parmetis/include --with-parmetis-lib=[/sandbox/balay/parmetis/lib/libparmetis.a,libmetis.a]

Note

  • Run ./configure --help to get the list of external packages and corresponding additional options (for example --with-mpiexec for MPICH).

  • Generally one would use either one of the above installation modes for any given package - and not mix these. (i.e combining --with-mpi-dir and --with-mpi-include etc. should be avoided).

  • Some packages might not support certain options like --download-PACKAGENAME or --with-PACKAGENAME-dir. Architectures like Microsoft Windows might have issues with these options. In these cases, --with-PACKAGENAME-include and --with-PACKAGENAME-lib options should be preferred.

  • --with-packages-build-dir=PATH: By default, external packages will be unpacked and the build process is run in $PETSC_DIR/$PETSC_ARCH/externalpackages. However one can choose a different location where these packages are unpacked and the build process is run.

BLAS/LAPACK#

These packages provide some basic numeric kernels used by PETSc. configure will automatically look for BLAS/LAPACK in certain standard locations, on most systems you should not need to provide any information about BLAS/LAPACK in the configure command.

One can use the following options to let configure download/install BLAS/LAPACK automatically:

  • When fortran compiler is present:

    $ ./configure --download-fblaslapack

  • Or when configuring without a Fortran compiler - i.e --with-fc=0:

    $ ./configure --download-f2cblaslapack

Alternatively one can use other options like one of the following:

$ ./configure --with-blaslapack-lib=libsunperf.a
$ ./configure --with-blas-lib=libblas.a --with-lapack-lib=liblapack.a
$ ./configure --with-blaslapack-dir=/soft/com/packages/intel/13/079/mkl

Intel MKL#

Intel provides BLAS/LAPACK via the MKL library. One can specify it to PETSc configure with --with-blaslapack-dir=$MKLROOT or --with-blaslapack-dir=/soft/com/packages/intel/13/079/mkl. If the above option does not work - one could determine the correct library list for your compilers using Intel MKL Link Line Advisor and specify with the configure option --with-blaslapack-lib

IBM ESSL#

Sadly, IBM’s ESSL does not have all the routines of BLAS/LAPACK that some packages, such as SuperLU expect; in particular slamch, dlamch and xerbla. In this case instead of using ESSL we suggest --download-fblaslapack. If you really want to use ESSL, see https://www.pdc.kth.se/hpc-services.

MPI#

The Message Passing Interface (MPI) provides the parallel functionality for PETSc.

MPI might already be installed. IBM, Intel, NVIDIA, and Cray provide their own and Linux and macOS package managers also provide open-source versions called MPICH and Open MPI. If MPI is not already installed use the following options to let PETSc’s configure download and install MPI.

  • For MPICH:

    $ ./configure --download-mpich

  • For Open MPI:

    $ ./configure --download-openmpi

  • To not use MPI:

    $ ./configure --with-mpi=0

  • To use an installed version of MPI

    $ ./configure --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90

  • The Intel MPI library provides MPI compiler wrappers with compiler specific names.

    GNU compilers: gcc, g++, gfortran:

    $ ./configure --with-cc=mpigcc --with-cxx=mpigxx --with-fc=mpif90

    “Old” Intel compilers: icc, icpc, and ifort:

    $ ./configure --with-cc=mpiicc --with-cxx=mpiicpc --with-fc=mpiifort

    they might not work with some Intel MPI library versions. In those cases, use

    $ export I_MPI_CC=icc && export I_MPI_CXX=icpc && export I_MPI_F90=ifort
$ ./configure --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90

  • “New” oneAPI Intel compilers: icx, icpx, and ifx:

    $ ./configure --with-cc=mpiicx --with-cxx=mpiicpx --with-fc=mpiifx

    they might not work with some Intel MPI library versions. In those cases, use

    $ export I_MPI_CC=icx && export I_MPI_CXX=icpx && export I_MPI_F90=ifx
$ ./configure --with-cc=mpicc --with-cxx=mpicxx --with-fc=mpif90

  • On Cray systems, after loading the appropriate MPI module, the regular compilers cc, CC, and ftn automatically become MPI compiler wrappers.

    $ ./configure --with-cc=cc --with-cxx=CC --with-fc=ftn

  • Instead of providing the MPI compiler wrappers, one can provide the MPI installation directory, where the MPI compiler wrappers are available in the bin directory, (without additionally specifying --with-cc etc.) using

    $  ./configure --with-mpi-dir=/absolute/path/to/mpi/install/directory

  • To control the compilers selected by mpicc, mpicxx, and mpif90 one may use environmental variables appropriate for the MPI libraries. For Intel MPI, MPICH, and Open MPI they are

    $ export I_MPI_CC=c_compiler && export I_MPI_CXX=c++_compiler && export I_MPI_F90=fortran_compiler
$ export MPICH_CC=c_compiler && export MPICH_CXX=c++_compiler && export MPICH_FC=fortran_compiler
$ export OMPI_CC=c_compiler && export OMPI_CXX=c++_compiler && export OMPI_FC=fortran_compiler

    Then, use

    $ ./configure --with-cc=mpicc --with-fc=mpif90 --with-cxx=mpicxx

    We recommend avoiding these environmental variables unless absolutely necessary. They are easy to forget or they may be set and then forgotten, thus resulting in unexpected behavior.

    And avoid using the syntax --with-cc="mpicc -cc=icx" - this can break some builds (for example: external packages that use CMake)

    Note

    The Intel environmental variables I_MPI_CC, I_MPI_CXX, and I_MPI_F90 also changing the behavior of the compiler-specific MPI compiler wrappers mpigcc, ``mpigxx, mpif90, mpiicx, mpiicpx, mpiifx, mpiicc, mpiicpc, and mpiifort. These variables may be automatically set by certain modules. So one must be careful to ensure they are using the desired compilers.

Installing With Open MPI With Shared MPI Libraries#

Open MPI defaults to building shared libraries for MPI. However, the binaries generated by MPI compiler wrappers mpicc/mpif90 etc. require $LD_LIBRARY_PATH to be set to the location of these libraries.

Due to this Open MPI restriction one has to set $LD_LIBRARY_PATH correctly (per Open MPI installation instructions), before running PETSc configure. If you do not set this environmental variables you will get messages when running configure such as:

UNABLE to EXECUTE BINARIES for config/configure.py
-------------------------------------------------------------------------------
Cannot run executables created with C. If this machine uses a batch system
to submit jobs you will need to configure using/configure.py with the additional option --with-batch.
Otherwise there is problem with the compilers. Can you compile and run code with your C/C++ (and maybe Fortran) compilers?

or when running a code compiled with Open MPI:

error while loading shared libraries: libmpi.so.0: cannot open shared object file: No such file or directory

Installing On macOS#

For development on macOS we recommend installing both the Apple Xcode GUI development system (install from the Apple macOS store) and the Xcode Command Line tools 2 install with

$ xcode-select --install

The Apple compilers are clang and clang++ 3. Apple also provides /usr/bin/gcc, which is, confusingly, a link to the clang compiler, not the GNU compiler.

We also recommend installing the package manager homebrew. To install gfortran one can use

$ brew update
$ brew list            # Show all packages installed through brew
$ brew upgrade         # Update packages already installed through brew
$ brew install gcc

This installs gfortran, gcc, and g++ with the compiler names gfortran-version (also available as gfortran), gcc-version and g++-version, for example gfortran-12, gcc-12, and g++-12.

After upgrading macOS, you generally need to update the Xcode GUI development system (using the standard Apple software update system), and the Xcode Command Line tools (run xcode-select --install again).

Its best to update brew after all macOS or Xcode upgrades (use brew upgrade). Sometimes gfortran will not work correctly after an upgrade. If this happens it is best to reinstall all brew packages using, for example,

$ brew leaves > list.txt         # save list of formulae to re-install
$ brew list --casks >> list.txt  # save list of casks to re-install
$ emacs list.txt                 # edit list.txt to remove any unneeded formulae or casks
$ brew uninstall `brew list`     # delete all installed formulae and casks
$ brew cleanup
$ brew update
$ brew install `cat list.txt`    # install needed formulae and casks

Installation Location: In-place or Out-of-place#

By default, PETSc does an in-place installation, meaning the libraries are kept in the same directories used to compile PETSc. This is particularly useful for those application developers who follow the PETSc git repository main or release branches since rebuilds for updates are very quick and painless.

Note

The libraries and include files are located in $PETSC_DIR/$PETSC_ARCH/lib and $PETSC_DIR/$PETSC_ARCH/include

Out-of-place Installation With --prefix#

To install the libraries and include files in another location use the --prefix option

$ ./configure --prefix=/home/userid/my-petsc-install --some-other-options

The libraries and include files will be located in /home/userid/my-petsc-install/lib and /home/userid/my-petsc-install/include.

Installs For Package Managers: Using DESTDIR (Very uncommon)#

$ ./configure --prefix=/opt/petsc/my-root-petsc-install
$ make
$ make install DESTDIR=/tmp/petsc-pkg

Package up /tmp/petsc-pkg. The package should then be installed at /opt/petsc/my-root-petsc-install

Multiple Installs Using --prefix (See DESTDIR)#

Specify a different --prefix location for each configure of different options - at configure time. For example:

$ ./configure --prefix=/opt/petsc/petsc-3.21.0-mpich --with-mpi-dir=/opt/mpich
$ make
$ make install [DESTDIR=/tmp/petsc-pkg]
$ ./configure --prefix=/opt/petsc/petsc-3.21.0-openmpi --with-mpi-dir=/opt/openmpi
$ make
$ make install [DESTDIR=/tmp/petsc-pkg]

In-place Installation#

The PETSc libraries and generated included files are placed in the sub-directory off the current directory $PETSC_ARCH which is either provided by the user with, for example:

$ export PETSC_ARCH=arch-debug
$ ./configure
$ make
$ export PETSC_ARCH=arch-opt
$ ./configure --some-optimization-options
$ make

or

$ ./configure PETSC_ARCH=arch-debug
$ make
$ ./configure --some-optimization-options PETSC_ARCH=arch-opt
$ make

If not provided configure will generate a unique value automatically (for in-place non --prefix configurations only).

$ ./configure
$ make
$ ./configure --with-debugging=0
$ make

Produces the directories (on an Apple macOS machine) $PETSC_DIR/arch-darwin-c-debug and $PETSC_DIR/arch-darwin-c-opt.

Installing On Machine Requiring Cross Compiler Or A Job Scheduler#

On systems where you need to use a job scheduler or batch submission to run jobs use the configure option --with-batch. On such systems the make check option will not work.

  • You must first ensure you have loaded appropriate modules for the compilers etc that you wish to use. Often the compilers are provided automatically for you and you do not need to provide --with-cc=XXX etc. Consult with the documentation and local support for such systems for information on these topics.

  • On such systems you generally should not use --with-blaslapack-dir or --download-fblaslapack since the systems provide those automatically (sometimes appropriate modules must be loaded first).

  • Some package’s --download-package options do not work on these systems, for example HDF5. Thus you must use modules to load those packages and --with-package to configure with the package.

  • Since building external packages on these systems is often troublesome and slow we recommend only installing PETSc with those configuration packages that you need for your work, not extras.

Installing With TAU Instrumentation Package#

TAU package and the prerequisite PDT packages need to be installed separately (perhaps with MPI). Now use tau_cc.sh as compiler to PETSc configure:

$ export TAU_MAKEFILE=/home/balay/soft/linux64/tau-2.20.3/x86_64/lib/Makefile.tau-mpi-pdt
$ ./configure CC=/home/balay/soft/linux64/tau-2.20.3/x86_64/bin/tau_cc.sh --with-fc=0 PETSC_ARCH=arch-tau

Installing PETSc To Use GPUs And Accelerators#

PETSc is able to take adavantage of GPU’s and certain accelerator libraries, however some require additional configure options.

CUDA#

Important

An NVIDIA GPU is required to use CUDA-accelerated code. Check that your machine has a CUDA enabled GPU by consulting https://developer.nvidia.com/cuda-gpus.

On Linux - make sure you have compatible NVIDIA driver installed.

On Microsoft Windows - Use either Cygwin or WSL the latter of which is entirely untested right now. If you have experience with WSL and/or have successfully built PETSc on Microsoft Windows for use with CUDA we welcome your input at petsc-maint@mcs.anl.gov. See the bug-reporting documentation for more details.

In most cases you need only pass the configure option --with-cuda; check config/examples/arch-ci-linux-cuda-double.py for example usage.

CUDA build of PETSc currently works on Mac OS X, Linux, Microsoft Windows with Cygwin.

Examples that use CUDA have the suffix .cu; see $PETSC_DIR/src/snes/tutorials/ex47.cu

Kokkos#

In most cases you need only pass the configure option --download-kokkos --download-kokkos-kernels and one of --with-cuda, --with-openmp, or --with-pthread (or nothing to use sequential Kokkos). See the CUDA installation documenation, Open MPI installation documentation for further reference on their respective requirements.

Examples that use Kokkos at user-level have the suffix .kokkos.cxx; see src/snes/tutorials/ex3k.kokkos.cxx. More examples use Kokkos through options database; search them with grep -r -l "requires:.*kokkos_kernels" src/.

OpenCL/ViennaCL#

Requires the OpenCL shared library, which is shipped in the vendor graphics driver and the OpenCL headers; if needed you can download them from the Khronos Group directly. Package managers on Linux provide these headers through a package named ‘opencl-headers’ or similar. On Apple systems the OpenCL drivers and headers are always available and do not need to be downloaded.

Always make sure you have the latest GPU driver installed. There are several known issues with older driver versions.

Run configure with --download-viennacl; check config/examples/arch-ci-linux-viennacl.py for example usage.

OpenCL/ViennaCL builds of PETSc currently work on Mac OS X, Linux, and Microsoft Windows.

Installing To Run in Browser with Emscripten#

PETSc can be used to run applications in the browser using https://emscripten.org, see https://emscripten.org/docs/getting_started/downloads.html, for instructions on installing Emscripten. Run

$  ./configure --with-cc=emcc --with-cxx=0 --with-fc=0 --with-ranlib=emranlib --with-ar=emar --with-shared-libraries=0 --download-f2cblaslapack=1 --with-mpi=0 --with-batch

Applications may be compiled with, for example,

$  make ex19.html

The rule for linking may be found in lib/petsc/conf/rules

Installing On Large Scale DOE Systems#

There are some notes on our GitLab Wiki which may be helpful in installing and running PETSc on large scale systems. Also note the configuration examples in config/examples.

Footnotes

1

All MPI implementations provide convenience scripts for compiling MPI codes that internally call regular compilers, they are commonly named mpicc, mpicxx, and mpif90. We call these “MPI compiler wrappers”.

2

The two packages provide slightly different (though largely overlapping) functionality which can only be fully used if both packages are installed.

3

Apple provides customized clang and clang++ for its system. To use the unmodified LLVM project clang and clang++ install them with brew.