title: In CUDA, what is memory coalescing, and how is it achieved?
body: <p>What is "coalesced" in CUDA global memory transaction? I couldn't understand even after going through my CUDA guide. How to do it? In CUDA programming guide matrix example, accessing the matrix row by row is called "coalesced" or col.. by col.. is called coalesced?
  Which is correct and why?</p>