calc_fftw3 Subroutine

public subroutine calc_fftw3(sens, tab_in, tab_ou, long, larg)

Note

Subroutine that transforms forward or backward a double complex array. For speed reasons FFTW will always work on the same memory area, until the plans are destroyed of course. 1 FFT distributed on several threads

Arguments

Type IntentOptional Attributes Name
integer(kind=I4), intent(in) :: sens

=FORWARD or =BACKWARD
complex(kind=R8), intent(in), dimension(1:long, 1:larg) :: tab_in

array to transform
complex(kind=R8), intent(out), dimension(1:long, 1:larg) :: tab_ou

transformed array
integer(kind=I4), intent(in) :: long

first 2D array dimension
integer(kind=I4), intent(in) :: larg

second 2D array dimension

Calls

proc~~calc_fftw3~~CallsGraph proc~calc_fftw3 calc_fftw3 interface~fftw_execute_dft fftw_execute_dft proc~calc_fftw3->interface~fftw_execute_dft interface~fftw_plan_with_nthreads fftw_plan_with_nthreads proc~calc_fftw3->interface~fftw_plan_with_nthreads omp_get_num_procs omp_get_num_procs proc~calc_fftw3->omp_get_num_procs proc~end_fftw3 end_fftw3 proc~calc_fftw3->proc~end_fftw3 proc~init_fftw3 init_fftw3 proc~calc_fftw3->proc~init_fftw3 proc~desalloc_fftw3 desalloc_fftw3 proc~end_fftw3->proc~desalloc_fftw3 proc~destroy_plan_fftw3 destroy_plan_fftw3 proc~end_fftw3->proc~destroy_plan_fftw3 proc~alloc_fftw3 alloc_fftw3 proc~init_fftw3->proc~alloc_fftw3 proc~make_plan_fftw3 make_plan_fftw3 proc~init_fftw3->proc~make_plan_fftw3 interface~fftw_alloc_complex fftw_alloc_complex proc~alloc_fftw3->interface~fftw_alloc_complex interface~fftw_free fftw_free proc~desalloc_fftw3->interface~fftw_free interface~fftw_destroy_plan fftw_destroy_plan proc~destroy_plan_fftw3->interface~fftw_destroy_plan interface~fftw_plan_dft_2d fftw_plan_dft_2d proc~make_plan_fftw3->interface~fftw_plan_dft_2d

Called by

proc~~calc_fftw3~~CalledByGraph proc~calc_fftw3 calc_fftw3 program~test_fftw3 test_fftw3 program~test_fftw3->proc~calc_fftw3

Source Code

   subroutine calc_fftw3(sens, tab_in, tab_ou, long, larg)
   implicit none
   integer(kind=I4), intent(in )                            :: sens     !! *```=FORWARD``` or ```=BACKWARD```*
   integer(kind=I4), intent(in )                            :: long     !! *first  2D array dimension*
   integer(kind=I4), intent(in )                            :: larg     !! *second 2D array dimension*
   complex(kind=R8), dimension(1:long, 1:larg), intent(in ) :: tab_in   !! *array to transform*
   complex(kind=R8), dimension(1:long, 1:larg), intent(out) :: tab_ou   !! *transformed array*

      if ( any( FFT_DIM(1:2) /= [long, larg] ) ) then

         if ( sum(FFT_DIM(1:2)) /= 0 ) call end_fftw3()

         call fftw_plan_with_nthreads(nthreads = omp_get_num_procs())
         call init_fftw3(long = long, larg = larg)

      endif

      select case(sens)

         case(FORWARD)
            cmp_f_i(1:long, 1:larg) = tab_in(1:long, 1:larg)
            call fftw_execute_dft(plan_f, cmp_f_i(1:long, 1:larg), cmp_f_o(1:long, 1:larg))
            tab_ou(1:long, 1:larg) = cmp_f_o(1:long, 1:larg)/sqrt(real(long*larg, kind=r8))

         case(BACKWARD)
            cmp_f_i(1:long, 1:larg) = tab_in(1:long, 1:larg)
            call fftw_execute_dft(plan_b, cmp_f_i(1:long, 1:larg), cmp_f_o(1:long, 1:larg))
            tab_ou(1:long, 1:larg) = cmp_f_o(1:long, 1:larg)/sqrt(real(long*larg, kind=r8))

      endselect

   return
   endsubroutine calc_fftw3