OpenGL vs. OpenCL, which to choose and why?

Question

What features make OpenCL unique to choose over OpenGL with GLSL for calculations? Despite the graphic related terminology and inpractical datatypes, is there any real caveat to

Answer 1

Another major reason is that OpenGL\GLSL are supported only on graphics cards. Although multi-core usage started with using graphics hardware there are many hardware vendors working on multi-core hardware platform targeted for computation. For example see Intels Knights Corner.

Developing code for computation using OpenGL\GLSL will prevent you from using any hardware that is not a graphics card.