This library provides a Testing and Timing code to asses the performance of your FFT, estimate the scalability and the size of your simulation. To compile the test program, once you have properly configure QE, go inside the directory FFTXlib and type: make TEST Then you can run your FFT tests using command like: mpirun -np 4 ./fft_test.x -ecutwfc 80 -alat 20 -nbnd 128 -ntg 4 or, in case of serial build ./fft_test.x -ecutwfc 80 -alat 20 -nbnd 128 -ntg 4 Command line arguments: -ecutwfc Plane wave energy cut off -alat Lattice parameter -nbnd Number of bands (fft cycles) -ntg Number of task groups