Docs: Installation: Configure

PETSc's New Configure

For version 2.1.5, we have rewritten the standard configure script in Python. This greatly increased its modularity and extensibility. All standard autoconf functionality is replicated, so that there is no division between the generation and execution of the configuration script.

This Python configure outputs files identical to those in the current PETSc bmake system. Thus, the user may edit these after configuration if necessary, and all current bmake configurations will continue to function properly. The Python Configure is currently a beta product and we do expect problems on some architectures. Please report all failures to petsc-maint@mcs.anl.gov along with the configure.log file from the directory in which configure was run, usually ${PETSC_DIR}. Please note that this configure requires python version 2.2 or newer.

Installing PETSc with Python Configure

setenv PETSC_DIR path_to_petsc_localtion
cd $PETSC_DIR
setenv PETSC_ARCH `bin/configarch`
./config/configure.py --help
./config/configure.py [configure options]
make BOPT=g all

To install PETSc with python configure - one has to set the PETSC_ARCH to the value detected by $PETSC_DIR/bin/configarch script. It is recommended to run the Python configure script from ${PETSC_DIR}. Options can be specified to this script exactly as with the familiar configure. config/configure.py will create files in bmake/$PETSC_ARCH dir. With these files, PETSc can now be build as usual with the command: make BOPT=g all

Notes

You must specify the PETSC_ARCH environment variable using $PETSC_DIR/bin/configarch , before running configure. You may also specify this variable as an argument to configure itself. The value of PETSC_ARCH must contain the configure guess for the architecture as a prefix, in order to prevent clashes with existing PETSc bmake files. If it does not, you will receive and error message like the following:

PETSC_ARCH (linux) does not have our guess (linux-gnu) as a prefix!

To output the full list of configure options, use configure.py --help. All options are valid with single or double dashes, so -help would also work.

In order to simplify this process, PETSc provides helper scripts for several architectures in the config directory. These scripts are intended as templates, for which you fill in the appropriate variables for your own system. For instance, on a Linux system, you might use config/configure.linux-gnu, changing the arguments in the script to reflect the locations of BLAS, LAPACK, and MPI on your system.

Specifying Packages

Currenlty configure can detect BLAS, LAPACK, MPI. Configure will look for standard packages in many well-known locations, however exhaustive searches are not only impractical, but can often locate an inappropriate version of the package. Therefore, it is often necessary to indicate the location of a given package on the system. We will take MPI as our example. Most packages can be specified by giving the include directory and a library, as in

configure.py --with-mpi-include=/usr/local/mpich/include --with-mpi-lib=/usr/local/mpich/lib/libmpich.a

Notice that the library argument indicates the actual library file rather than the directory. In the case of MPI, we also need an additional argument to indicate that it is active:

configure.py --with-mpi --with-mpi-include=/usr/local/mpich/include --with-mpi-lib=/usr/local/mpich/lib/libmpich.a

In addition, MPI installations often have a predictable interior structure, in which case it is enough to specify the root directory of the installation:

configure.py --with-mpi --with-mpi-dir=/usr/local/mpich

Some packages, such as BLAS and LAPACK, are primarily Fortran and thus have no include directory.

Maintaining Multiple Configurations

You may maintain multiple configurations in the same way as the current PETSc. Each configuration is assigned a different PETSC_ARCH, and stored in a different bmake directory. For instance:

cd $PETSC_DIR
./config/configure_linux-gnu.py -PETSC_ARCH=linux-gnu
./config/configure_linux-gnu.py -PETSC_ARCH=linux-gnu-intel --with-cc=icc

Coping with Failures

It will not be unusual in this beta phase of the Python configure for configuration failures to occur. The most important source of information in these instances is the configure.log file, written in the directory from which configure was run. This file is always appended to, so make sure to first locate the banner corresponding to the last configure run. This banner contains the time of the run, configure options, and current working directory. Each test begins with a separator line. Then its name and module are given, followed by a general documentation line. Afterwards can be several lines of specific information, such as shell actions, specific headers, libraries, or functions involved, and so on. If a compile or link fails, we attempt to provide the error message in this log.

Additional Notes

The core modules exist in the BuildSystem.config package, whereas the custom PETSc configuration is present in the PETSc.Configure module. Users may augment the system with custom modules specified using the -configModules flag.