InstallingclAmdFft

Important note: clAmdFft (used by ADDA v.1.3b4) is no more available for download. However, the most recent source of ADDA is already using its predecessor clFFT. Unfortunately, we have not yet completed the detailed procedure for its installation, but it should be similar to the one described below. See also issue 204.

clAmdFft library provides the default way to perform the FFTs in OpenCL version of ADDA. This library already significantly outperforms the built-in Apple clFFT routines and is expected to develop further. Therefore, its use on any system with GPU is highly recommended. The following guidelines are based on clAmdFft version 1.10.274 (or 321).

Unix

• Download(broken) the package of clAmdFft for Linux and install it. The default installation directory is /opt/clAmdFft-<version>. It is also possible to specify any other directory, for example, inside the home directory of a particular user.

• Either

  • specify paths to include and lib64 (or lib32) subdirectories of the install directory in file src/ocl/Makefile, as described in CompilingADDA.
  • or add .../include to environmental variable C_INCLUDE_PATH and .../lib64 (or lib32) - to LIBRARY_PATH and LD_LIBRARY_PATH (for linking and runtime). Setting LD_LIBRARY_PATH can be replaced by modifying /etc/ld.so.conf or by sourcing appmlEnv.sh in the installation directory.

• There is a known bug when using clAmdFft together with libOpenCL.so provided by Nvidia GPU driver. During linking spurious errors appear, like:

  ...libclAmdFft.Runtime.so: undefined reference to `cl...@OPENCL_1.0'
  

  It has been discussed in a few places (1, 2, 3). Currently, the simplest workaround seems to uncomment the line

  LDFLAGS +=-Wl,--unresolved-symbols=ignore-in-shared-libs
  

  in src/ocl/Makefile. On Unix it is even better to switch to open-source implementation of libOpenCL.so (see OpenCL#Headers_and_libraries)

• Also on Unix clAmdFft may need pthread library, which is not linked by default. One way to fix this problem is to uncomment the following line in src/ocl/Makefile.

  LDLIBS += -lpthread
  

Windows

If you just want to use ADDA executables for Windows, do not worry about clAmdFft at all. An appropriate DLL is included in the corresponding package.

If you want to compile adda_ocl on Windows yourself, proceed further:

• Download(broken) the installer of clAmdFft for Windows and install it. The default installation directory is C:\Program Files (x86)\AMD\clAmdFft or C:\Program Files\AMD\clAmdFft.
• Add bin64 or bin32 (depending on the Windows bitness) subdirectory in the installation directory to Windows environmental variable PATH
• Either
  • specify paths to include and bin64 (or bin32) subdirectories of the install directory in file src/ocl/Makefile, as described in CompilingADDA. The compiler will link directly to *.dll (instead of *.lib).
  • or copy contents of include folder and clAmdFft.Runtime.dll of bin folder to corresponding include and lib folders of the MinGW/MSYS environment.