fftw_complex in[N], out[N];
        fftw_plan plan;

        plan = fftw_plan_dft_1d(N,in,out,FFTW_FORWARD,FFTW_ESTIMATE);
        fftw_execute(plan);
        fftw_destroy_plan(plan);

        double complex in, out
        dimension in(N), out(N)
        integer*8 plan

        call dfftw_plan_dft_1d(plan,N,in,out,FFTW_FORWARD,FFTW_ESTIMATE)
        call dfftw_execute_dft(plan, in, out)
        call dfftw_destroy_plan(plan)