The actual version of Open MPI compile and run under Windows. The simplest
way to get access to a windows distribution is to download one from the
download section on the Open MPI web site (http://www.open-mpi.org) or to
check it out via SVN (information on the above mentioned web-site).

The rest of the document is divided on 2. The first section is for an easy setup,
based on some files we distribute (32 and 64 bits versions). The second one is
only for advanced users, who want to deeply dig into the software.

First approach: Simple and strait-forward

Step 1: untar in the root directory of the Open MPI distribution one of our tgz
        file from contrib/platform/win32/

Step 2: go in ompi/datatype and copy
        datatype_pack.c   to datatype_pack_checksum.c
        datatype_unpack.c to datatype_unpack_checksum.c
        
Step 3: Add the following to ompi/tools/ompi_info/ompi_info.h after you
        change the relevant information inside (replace everything between @).

#define OMPI_CONFIGURE_USER "@USER_NAME@"
#define OMPI_CONFIGURE_HOST "@HOST_NAME@"
#define OMPI_CONFIGURE_DATE "@TODAY_DATE@"
#define OMPI_BUILD_USER OMPI_CONFIGURE_USER
#define OMPI_BUILD_HOST OMPI_CONFIGURE_HOST
#define OMPI_BUILD_DATE OMPI_CONFIGURE_DATE
#define OMPI_BUILD_CFLAGS "/Od /Gm /EHsc /RTC1 /MDd"
#define OMPI_BUILD_CPPFLAGS "-I${HOME}/ompi-trunk -I${HOME}/opal/include -I${HOME}/ompi-trunk/orte/include -I${HOME}/ompi-trunk/ompi/include"
#define OMPI_BUILD_CXXFLAGS "/Od /Gm /EHsc /RTC1 /MDd"
#define OMPI_BUILD_CXXCPPFLAGS "-I${HOME}/ompi-trunk -I../../.. -I$(HOME}/ompi-trunk/opal/include -I${HOME}/ompi-trunk/orte/include -I${HOME}/ompi-trunk/ompi/include"
#define OMPI_BUILD_FFLAGS ""
#define OMPI_BUILD_FCFLAGS ""
#define OMPI_BUILD_LDFLAGS " "
#define OMPI_BUILD_LIBS " "
#define OMPI_CC_ABSOLUTE "cl"
#define OMPI_CXX_ABSOLUTE "cl"
#define OMPI_F77_ABSOLUTE "none"
#define OMPI_F90_ABSOLUTE "none"
#define OMPI_F90_BUILD_SIZE "small"

Step 4: Open the Open MPI project (.sln file) from the root directory of the distribution
Step 5: Choose which version you want to build (from the project manager)
Step 6: Add the build directory to your PATH
Step *: Have fun ...
Step *+1: If you have any problems, find any bugs please feel free to report to
          users@open-mpi.org

Second approach: Confirmed users

The rest of this document is only for confirmed developers, who has spare
time or an urgent necessity to compile their own windows version.

Compiling Open MPI natively on Windows require several tools. Of course
one need the Microsoft Visual Studio for their C/C++ compiler as well as
for the ml (assembler compiler) and the link utilities. But the current
version require some GNU tools as well. Here is the list of such tools:
1. Download any Unix for Windows environment. I have successfully used
  cygwin and minGW.
2. Make the default shell ash.exe (install it if it's not installed by
  default) as it will highly decrease the configuration and compilation
  time.
3. Download a very recent libtool (I'm using the pre 2.0 from their CVS HEAD).

Now you should be set. The most difficult part is done. Just use your favorite
shell to get a window, go in the ompi directory and ... do like in any
UNIX environments: configure and make.

All questions, complaints and requests about the Windows port should be sent 
by email to bosilca at open-mpi dot org.