Oscar's blog gives you also a lot of informations about the differences in AMD OpenCL, Apple OpenCL, IBM OpenCL and NVIDIA OpenCL

OpenCL-z by oscarbg3 November 2009
Notes
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Works with Nvidia 195.39 OpenCL ICD or higher
Works with CPUs and AMDs GPUs with AMD Stream 2.0beta4 and Catalyst 9.11 or higher
Autodetects in displays info of AMD and Nvidia OpenCL drivers in a single launch in current form..
For detecting AMD drivers you need to define the enviroment variable ATISTREAMSDKROOT where the SDK is ..
I think in Windows this is done in the installer in Linux use something as
export ATISTREAMSDKROOT..