Add appropriate size checkers for fft and format

Author: Anand

src/common/m_mpi_common.fpp

@@ -1165,7 +1165,7 @@ contains
             if (p > 0) then
 
 #ifdef MFC_POST_PROCESS
-                if(fft_wrt .and. (.not. file_per_process)) then 
+                if (fft_wrt .and. (.not. file_per_process)) then
 
                     ! Initial estimate of optimal processor topology
                     num_procs_x = 1
@@ -1269,7 +1269,7 @@ contains
                         end if
 
                     end do
-                end if    
+                end if
 #else
                 if (cyl_coord .and. p > 0) then
                     ! Implement pencil processor blocking if using cylindrical coordinates so

src/post_process/m_checker.fpp

@@ -17,7 +17,7 @@ module m_checker
 
     implicit none
 
-    private; public :: s_check_inputs
+    private; public :: s_check_inputs, s_check_inputs_fft
 
 contains
 
@@ -32,7 +32,6 @@ contains
         call s_check_inputs_flux_limiter
         call s_check_inputs_volume_fraction
         call s_check_inputs_vorticity
-        call s_check_inputs_fft
         call s_check_inputs_qm
         call s_check_inputs_liutex
         call s_check_inputs_schlieren
@@ -112,11 +111,19 @@ contains
         @:PROHIBIT(any(omega_wrt) .and. fd_order == dflt_int, "fd_order must be set for omega_wrt")
     end subroutine s_check_inputs_vorticity
 
-     !> Checks constraints on fft_wrt
+    !> Checks constraints on fft_wrt
     impure subroutine s_check_inputs_fft
+        integer :: num_procs_x, num_procs_y, num_procs_z
+
         @:PROHIBIT(fft_wrt .and. file_per_process, "Turn off file_per_process with fft_wrt")
         @:PROHIBIT(fft_wrt .and. (n == 0 .or. p == 0), "FFT WRT only in 3D")
         @:PROHIBIT(fft_wrt .and. (MOD(m+1,2) == 1 .or. MOD(n+1,2) == 1 .or. MOD(p+1,2) == 1), "FFT WRT requires local dimensions divisible by 2")
+        num_procs_x = (m_glb + 1)/(m + 1)
+        num_procs_y = (n_glb + 1)/(n + 1)
+        num_procs_z = (p_glb + 1)/(p + 1)
+        @:PROHIBIT(fft_wrt .and. (MOD(m_glb+1,num_procs_y) /= 0 .or. MOD(m_glb+1,num_procs_z) /= 0), "FFT WRT requires m_glb to be divisble by num_procs_y and num_procs_z")
+        @:PROHIBIT(fft_wrt .and. (MOD(n_glb+1,num_procs_y) /= 0 .or. MOD(n_glb+1,num_procs_z) /= 0), "FFT WRT requires n_glb to be divisble by num_procs_y and num_procs_z")
+        @:PROHIBIT(fft_wrt .and. (MOD(p_glb+1,num_procs_y) /= 0 .or. MOD(p_glb+1,num_procs_z) /= 0), "FFT WRT requires p_glb to be divisble by num_procs_y and num_procs_z")
     end subroutine s_check_inputs_fft
 
     !> Checks constraints on Q-criterion parameters