Quick and dirty test with transposing the data for allowing batch FFT over entire domain in y-direction.
Cleanup, and added transpose for non-square grids
y-direction FFT with transpose on non-square grids working
Unfortunately the speedup by doing a transpose before the y-direction FFT only works (very well) for small grid sized, tipping point is somewhere around 128-256 grid points
Calculate dimensions thread block from grid dimensions. For small grid (an my slow home gpu) another factor ~2 faster
Quick check if cufftplan failed.
minor cleanup
Minor cleanup of unused FFT plans
Moved forward and backward FFTs to their own routines to cleanup the pressure exec function