How to transpose a matrix in an optimal way using blas?

c cuda blas cublas
Martin Kristiansen picture Martin Kristiansen · Oct 16, 2011 · Viewed 9.9k times · Source

I'm doing some calculations, and doing some analysis on the forces and weakness of different BLAS implementations. however I have come across a problem.

I'm testing cuBlas, doing linAlg on the GPU would seem like a good idea, but there is one problem.

The cuBlas implementation using column-major format, and since this is not what I need in the end, I'm curious if there is a way in with one can make BLAS do matrix-transpose?

Answer

talonmies picture talonmies · Oct 16, 2011

BLAS doesn't have a matrix transpose routine built in. The CUDA SDK includes a matrix transpose example with a paper which discusses optimal strategy for performing a transpose. Your best strategy is probably to use row major inputs to CUBLAS with the transpose input version of the calls, then perform the intermediate calculations in column major, and lastly perform a transpose operation afterwards using the SDK transpose kernel.

Edited to add that CUBLAS added a transpose routine in CUBLAS version 5, geam, which can performed matrix transposition in GPU memory and should be regarded as optimal for whatever architecture you are using.

Related questions

printf inside CUDA __global__ function

I am currently writing a matrix multiplication on a GPU and would like to debug my code, but since I can not use printf inside a device function, is there something else I can do to see what is going …

Read More
Fortran vs C++, does Fortran still hold any advantage in numerical analysis these days?

With the rapid development of C++ compilers,especially the intel ones, and the abilities of directly applying SIMD functions in your C/C++ codes, does Fortran still hold any real advantage in the world of numerical computations? I am from …

Read More
Use of cudamalloc(). Why the double pointer?

I am currently going through the tutorial examples on http://code.google.com/p/stanford-cs193g-sp2010/ to learn CUDA. The code which demostrates __global__ functions is given below. It simply creates two arrays, one on the CPU and one on …

Read More