Are there any public OpenCL C libraries?

Question

The title says it all, but to be even clearer: I'm looking for libs / collections of OpenCL C (kernel) code, not libs that use / provide an interface to OpenCL. Also, my interest is not restricted to a specific use case. Therefore the question is intentionally vague. Ideally, answers provide a name, description and link to projects that provide useful OpenCL C code snippets.

Edit: I will try to consolidate all answers here

• Samples from the AMD APP SDK
• Samples by NVIDIA
• Samples from the Intel FPGA OpenCL SDK

Answer 1

AMD used to have good code examples. They did work quite well on older AMD GPUs. Here is what I have found:

AMD APP SDK

Answer 2

This link Intel FPGA OpenCL SDK says that you can get OpenCL design examples inside Intel SDK.