Technically, GROMACS can be compiled on any platform with an ANSI C99
and C++98 compiler, and their respective standard C/C++ libraries.
+We use only a few C99 features, but note that the C++ compiler also needs to
+support these C99 features (notably, int64_t and related things), which are not
+part of the C++98 standard.
Getting good performance on an OS and architecture requires choosing a
good compiler. In practice, many compilers struggle to do a good job
optimizing the GROMACS architecture-optimized SIMD kernels.
cmake .. -DCMAKE_C_COMPILER=mpicc \
-DCMAKE_CXX_COMPILER=mpicxx \
- -DCMAKE_TOOLCHAIN_FILE=Platform/BlueGeneQ-static-XL-CXX \
+ -DCMAKE_TOOLCHAIN_FILE=Platform/BlueGeneQ-static-XL-CXX.cmake \
-DCMAKE_PREFIX_PATH=/your/fftw/installation/prefix \
-DGMX_MPI=ON \
-DGMX_BUILD_MDRUN_ONLY=ON
This is the architecture of the K computer, which uses Fujitsu
`Sparc64VIIIfx` chips. On this platform, GROMACS @PROJECT_VERSION@ has
-accelerated group kernels, no accelerated Verlet kernels, and a custom
-build toolchain.
+accelerated group kernels using the HPC-ACE instructions, no
+accelerated Verlet kernels, and a custom build toolchain. Since this
+particular chip only does double precision SIMD, the default setup
+is to build Gromacs in double. Since most users only need single, we have added
+an option GMX_RELAXED_DOUBLE_PRECISION to accept single precision square root
+accuracy in the group kernels; unless you know that you really need 15 digits
+of accuracy in each individual force, we strongly recommend you use this. Note
+that all summation and other operations are still done in double.
+
+The recommended configuration is to use
+
+ cmake .. -DCMAKE_TOOLCHAIN_FILE=Toolchain-Fujitsu-Sparc64-mpi.cmake \
+ -DCMAKE_PREFIX_PATH=/your/fftw/installation/prefix \
+ -DCMAKE_INSTALL_PREFIX=/where/gromacs/should/be/installed \
+ -DGMX_MPI=ON \
+ -DGMX_BUILD_MDRUN_ONLY=ON \
+ -DGMX_RELAXED_DOUBLE_PRECISION=ON
+ make
+ make install
### Intel Xeon Phi ###