FFT exercise 3

Make a parallel program that computes the Fourier Transform of a 3D set of data, using the following specifications:

- Use Fortran or C.

- Use MPI and MPI version of FFTW.

- Input array: Complex array of 128x128x128 points.

- Input function: 3D-Top Hat function centered in (63,63,63) (or (64,64,64) for Fortran users) and radius 32 points.

- Output array: Complex array of 128x128x128 points.

- Using the results, compute the anti-transform, and compare the results.

- For FFTW commands you can use the FFTW on line manual at http://www.fftw.org/doc/

- Use MPI_WTIME function: MPI_Wtime.html

- Compare the times of execution obtained using 2,4, 8, 16, 32, 48 cores.