# Installing PETSc On Microsoft Windows#

Are You Sure?

Are you sure you want to use Microsoft Windows? We recommend using Linux if possible (and minimize troubleshooting Microsoft Windows related issues).

## Installation With Microsoft/Intel Windows Compilers#

Microsoft Windows does not provide the same Unix shell environment as the other OSes. Also the default Microsoft/Intel compilers behave differently than other Unix compilers. So to install PETSc on Microsoft Windows - one has to install Cygwin (for the Unix environment) and use win32fe 1 (located at $PETSC_DIR/lib/petsc/bin/win32fe, to interface to Microsoft/Intel compilers). 1. Install Cygwin: Download and install Cygwin from http://www.cygwin.com and make sure the following components are installed: Note Make sure the following Cygwin components are installed: • python3 • make • (default selection should already have diff and other tools) Additional Cygwin components like git and CMake can be useful for installing external packages. 2. Remove Cygwin link.exe: Cygwin link.exe can conflict with Intel ifort compiler. If you are using ifort - do (from Cygwin terminal/bash-shell): $ mv /usr/bin/link.exe /usr/bin/link-cygwin.exe

3. Setup Cygwin terminal/bash-shell with Working Compilers:

We require the compilers to be setup properly in a Cygwin bash command shell, so that cl foo.c or ifort foo.f works from this shell. For example - if using VS2005 C and Intel 10 Fortran one can do:

1. Start > Programs > Intel Software Development Tools > Intel Fortran Compiler 10 > Visual Fortran Build Environment (32bit or 64bit depending on your usage). This should start a “dos cmd” shell.

2. Within this shell - run Cygwin terminal/bash-shell mintty.exe as:

$C:\cygwin\bin\mintty.exe  3. Verify if the compilers are useable (by running cl, ifort in this Cygwin terminal/bash-shell). 4. Now run configure with win32fe 1 and then build the libraries with make (as per the usual instructions) ### Example Configure Usage With Microsoft Windows Compilers# Use configure with VC2005 C and Intel Fortran 10 (without MPI): $ ./configure --with-cc='win32fe cl' --with-fc='win32fe ifort' --with-cxx='win32fe cl' --with-mpi=0 --download-fblaslapack


If fortran, c++ usage is not required, use:

$./configure --with-cc='win32fe cl' --with-fc=0 --with-cxx=0 --download-f2cblaslapack  #### Using MPI# We support both MS-MPI [64-bit] and Intel MPI on Microsoft Windows (MPICH2 does not work, do not use it). For example usages, check $PETSC_DIR/config/examples/arch-mswin*.py

Warning

Avoid spaces in $PATH Its best to avoid spaces or similar special chars when specifying configure options. On Microsoft Windows - this usually affects specifying MPI or MKL. Microsoft Windows supports dos short form for dir names - so its best to use this notation. Cygwin tool cygpath can be used to get paths in this notation. For example: $ cygpath -u cygpath -ms '/cygdrive/c/Program Files (x86)/Microsoft SDKs/MPI'
/cygdrive/c/PROGRA~2/MICROS~2/MPI
$cygpath -u cygpath -ms '/cygdrive/c/Program Files (x86)/IntelSWTools/compilers_and_libraries/windows/mkl/lib/intel64' /cygdrive/c/PROGRA~2/INTELS~1/COMPIL~2/windows/mkl/lib/intel64  Then use in configure as follows: $ ./configure --with-cc='win32fe cl' --with-fc='win32fe ifort' --with-cxx='win32fe cl' \
--with-shared-libraries=0 \
--with-mpi-include='[/cygdrive/c/PROGRA~2/MICROS~2/MPI/Include,/cygdrive/c/PROGRA~2/MICROS~2/MPI/Include/x64]' \
--with-mpi-lib='-L/cygdrive/c/PROGRA~2/MICROS~2/MPI/lib/x64 msmpifec.lib msmpi.lib' \
--with-mpiexec=/cygdrive/c/PROGRA~1/MICROS~2/Bin/mpiexec \
--with-blaslapack-lib='-L/cygdrive/c/PROGRA~2/INTELS~1/COMPIL~2/windows/mkl/lib/intel64 mkl_intel_lp64_dll.lib mkl_sequential_dll.lib mkl_core_dll.lib'


#### External Packages#

The --download-package option works with many external packages on Microsoft Windows, but there may be some portability issues with others. Let us know your experience and we will either try to fix them or report them upstream.

#### Project Files#

We cannot provide Microsoft Visual Studio project files for users as they are specific to the configure options, location of external packages, compiler versions etc. used for any given build of PETSc, so they are potentially different for each build of PETSc. So if you need a project file for use with PETSc - do the following.

1. Create an empty project file with one of the examples say $PETSC_DIR/src/ksp/ksp/tutorials/ex2.c 2. Try compiling the example from Cygwin bash shell - using makefile - i.e.: $ cd $PETSC_DIR/src/ksp/ksp/tutorials$ make ex2

3. If the above works - then make sure all the compiler/linker options used by make are also present in the project file in the correct notation.

4. If errors - redo the above step. If all the options are correctly specified, the example should compile from MSDev.

#### Debugger#

Running PETSc probrams with -start_in_debugger is not supported on this platform, so debuggers will need to be initiated manually. Make sure your environment is properly configured to use the appropriate debugger for your compiler. The debuggers can be initiated using Microsoft Visual Studio 6:

$msdev ex1.exe  Microsoft Visual Studio .NET: $ devenv ex1.exe


Intel Enhanced Debugger:

$edb ex1.exe  or GNU Debugger $ gdb ex1.exe


### Notes On Using Other Systems Besides Cygwin To Compile With Microsoft/Intel Compilers#

For any alternate system, we would have to redo win32fe 1 functionality for that system. This includes:

• Marshal Unix type compiler options to Cl (Microsoft compiler).

• Convert paths in some of these options from this system (for example Cygwin paths) to Microsoft Windows paths.

• Have python that works with system path notation.

• Have the ability equivalent to Microsoft Windows process spawning; Cygwin process spawning produces Microsoft Windows processes. WSL1 lacked this.

## Installation With MSYS2 and MinGW Compilers#

This allows one to build standalone Microsoft Windows libraries and applications that are compatible with the Microsoft and Intel compilers.

1. Install MSYS2 and MS-MPI:

Download and install MSYS2 from https://www.msys2.org. If you want to use MPI, we recommend you use MS-MPI from https://learn.microsoft.com/en-us/message-passing-interface/microsoft-mpi.

2. Update MSYS2 and install base packages:

First, launch a MSYS2 MinGW x64 shell. Double-check this is the proper type of shell by typing

$echo$MINGW_PREFIX
/mingw64


If you see something else, e.g., /clang64, this is not the correct type of shell, it may still work, but this is less tested. Then, update your installation using pacman (you may be asked to quit and re-open your shell).

$pacman -Syu  Install the following packages that are needed by some PETSc dependencies. $  pacman -S autoconf automake-wrapper bison bsdcpio make git \
mingw-w64-x86_64-toolchain patch python flex \
pkg-config pkgfile tar unzip mingw-w64-x86_64-cmake \
mingw-w64-x86_64-msmpi mingw-w64-x86_64-openblas mingw-w64-x86_64-jq

3. Configuring:

The two difficulties here are: 1) make sure PETSc configure picks up the proper Python installation, as there are more than one available in a MSYS2 MinGW shell and 2) tell PETSc where is MS-MPI mpiexec. We also recommend not to use shared libraries as it is easier to create standalone binaries that way.

$/usr/bin/python ./configure --with-mpiexec='/C/Program\ Files/Microsoft\ MPI/Bin/mpiexec' \ --with-shared-libraries=0  Footnotes 1(1,2,3,4) PETSc win32 front end (win32fe): This tool is used as a wrapper to Microsoft and Intel compilers and associated tools - to enable building PETSc libraries using Cygwin make and other Unix tools. For additional info, run ${PETSC_DIR}/lib/petsc/bin/win32/win32fe without any options.