Performance of FORTRAN and C GPU Extensions for a Benchmark Suite of   Fourier Pseudospectral Algorithms
  A comparison of PGI OpenACC, FORTRAN CUDA, and Nvidia CUDA pseudospectral methods on a single GPU and GCC FORTRAN on single and multiple CPU cores is reported. The GPU implementations use CuFFT and the CPU implementations use FFTW. Porting pre-existing FORTRAN codes to utilize a GPUs is efficient and easy to implement with OpenACC and CUDA FORTRAN. Example programs are provided. 
B. Cloutier and B. K. Muite and P. Rigge
physics.comp-ph cs.MS