program speedtest
	use kind_defs
	use FourierTransform
	implicit none
	integer, parameter :: Nmax = 18
	integer :: N, i
	real(dbl) :: t1, t2, x(2**Nmax)
	complex(dbl) :: c(2**Nmax)

	! Read data:
	call random_number(x)

	do i = 4,Nmax
		N = 2**i
	
		call cpu_time(t1)
		c(1:N) = fft(x(1:N))
		call cpu_time(t2)
	
		print *, N, (t2-t1)*1000
	enddo

end program