Special mathematical functions implemented in GPU hardware

Question

I learnt today that in NVIDIA GPUs there are in the vertex unit special hardware functions for calculating linear interpolation in a 3D regular grid. I wonder if there are more of this kind and more important, if people really use them when they do GPGPU to accelerate codes

Answer 1

There are a number of functions that are implemented in hardware. The term you're looking for are "CUDA intrinsic functions." The linear interpolation is handled by textures, which is something similar.

See here: http://developer.download.nvidia.com/compute/DevZone/docs/html/C/doc/CUDA_C_Programming_Guide.pdf

The intrinsic functions are typically spelled with leading double underscores, like __sin, or enabled globally with the --use_fast_math nvcc option.

And yes, they're actually used quite often. :) They are slightly more inaccurate from a numerical perspective, so passing the results of one intrinsic into another repeatedly can have unacceptable error, depending on your use case. Testing is key.