Portability

Enabled compiling CUDA device code with clang

clang can be used as a device compiler by setting GMX_CLANG_CUDA=ON. A CUDA toolkit (>=7.0) is also needed. Note that the resulting runtime performance is usually worse than that of binaries compiled by the official NVIDIA CUDA compiler (nvcc).

Increased the oldest cmake, compiler and CUDA versions required

We now require gcc-4.8.1, clang-3.3 and icc-15, so we can rely on full C++11 support. We now also require CUDA-6.5 and CMake-3.4.3.

Added check that CUDA available hardware and compiled code are compatible

Added an early check to detect when the gmx mdrun binary does not embed code compatible with the GPU device it tries to use nor does it have PTX that could have been just-in-time compiled.

Additionally, if the user manually sets GMX_CUDA_TARGET_COMPUTE=20 and no later SM or COMPUTE but runs on >2.0 hardware, we’d be executing just-in-time-compiled Fermi kernels with incorrect host-side code assumptions (e.g amount of shared memory allocated or texture type). This change also prevents such cases.

Fixes Issue 2273

Disabled ARM Neon native rsqrt iteration used in short-ranged interactions

Fixes Issue 2261

Avoided FTZ triggering simd test failures

For very small arguments on platforms without FMA support, the Intel compiler’s default usage of flush-to-zero for denormal values can lead to slight deviations. Since this is a range we really don’t care about, and non-FMA platforms are anyway a thing of the past, just avoid testing a very small range around that threshold for non-FMA SIMD platforms.

Issue 2335

Fixed OpenCL compiles on Mac OS

Confirmed to work on Mac OS 10.13.2 running on a Macbook Pro with Radeon Pro 560.

Issue 2369

Tested that nvcc/host compiler combination works

We now compile a trivial CUDA program during a run of CMake to catch both unsupported nvcc/host compiler version combinations and other unknown errors.

Issue 1616

Added AVX_512 and KNC symbols to FFTW SIMD test

Otherwise the CMake code might complain loudly about FFTW not being accelerated on KNC or KNL hosts.

Implemented changes for CMake policy 0068

CMake-3.9 introduced a changed behavior for RPATH vs. install_name options on OS X. This avoids relying on functionality that will be removed in future CMake versions.