Compiling FFTW-2.1.5 for MPI and OpenMP

[Izaak_Beekman]

I was wondering if any one has experience compiling FFTW-2.1.5 with icc 11.1.046. When I run the ./configure script with the following flags I get the message: 'configure: error: don't know how to enable OpenMP'.

./configure --enable-mpi --enable-threads --with-openmp --prefix=

Now I *think* I just need to add the -openmp flag to icc to enable this. Does anyone know how i can tell the configure script that openmp can be enabled with this compiler flag? The script just dies when when it can't figure out openmp.

Also, it complains about not being able to use the following compiler flags:

-fno-schedule-insns -fschedule-insns2 -fstrict-aliasing

From looking through the icc documentation it looks as though -fstrict-aliasing can be replaced with the -ansi-alias flag. I am not sure what to do to replace the other flags.

-Z

[TimP]

If you are using icc, but not ifort, the C++ forum would be more appropriate.
For the Intel compilers, you are correct, -openmp is equivalent to gnu -fopenmp, and you have figured out the icc equivalent on aliasing. The gnu schedule-insns flags usage is probably not even portable among different major versions of gcc, and should be ignored.

[Izaak_Beekman]

Thanks Tim. Also how do I "tell" the ./configure script that I know how to solve the issue? I have only limited experience using autoconf, etc.

[TimP]

It's hard to give advice if an autoconfigure is set up to depend on a narrow range of gcc compilers. If you can't get help from the developers, or from Intel papers on fftw, you might allow it to configure against the gcc which you intend to have active under icc, then make necessary edits yourself to the resulting Makefile to change to icc. Isn't there already an fftw in the icc installation?

[Izaak_Beekman]

No fftw in the installation that I can find, but haven't looked at the MKL documentation, it might be hiding in there. The bottom line though is that I need MPI and OpenMP enabled FFTW, and with the old 2.x API.