Using MPI and FFTW with LAMMPS under Windows
from Timothy Lau <ttl@MIT.EDU>
(the referenced step #'s refer to the notes.2 document)

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If the user would like to use FFT with LAMMPS, he can download the source code
for FFTW 2.1.5 and dump all the files into the same directory as LAMMPS. Then
he can add to the project all the .c and .h files of FFTW as though those were
LAMMPS files.  Instead of following step 3 of the instructions, however, the
following should be added to fft3d.h:

#ifndef FFT_FFTW
#define FFT_FFTW
#endif

The user must take care to check for a Visual Studio compile that the "WIN32"
variable is defined although it is likely that Visual Studio would
automatically define this. Refer to line 137 of fftw.h that comes with FFTW
2.1.5.

If the user would like to use MPI with his Microsoft Visual Studio compile for
use on a multicore processor or for use on a Windows cluster, it has been
observed that MPICH 2 (at least the IA32 version) is known to compile with
LAMMPS in Visual Studio. Instead of following step 5 of the instructions, the
user could add the MPICH2\include as an additional include directory for MSVS
to find "mpi.h" and also add the MPICH2\lib as an additional link directory. He
should add mpi.lib to be specifically linked to.

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To compile LAMMPS with MPI-2 (e.g. MPICH 2) on Windows, you need
to use the MPICH_IGNORE_CXX_SEEK preprocessor definition.
