Changes between Version 3 and Version 4 of 2021WP/KNL-02_Jerome_RK3_stage1_tsplit

Timestamp:

2021-03-04T08:33:50+01:00 (3 years ago)

Author:

jchanut

Comment:

--

2021WP/KNL-02_Jerome_RK3_stage1_tsplit

@@ -23 +23 @@
 1) Simplify/clean the actual split-explicit procedure: 
 - Remove " centred integration" of barotropic mode (ln_bt_fw=F), which is only relevant with LF-RA and not compatible with AGRIF. 
-- Set initialization of filtering weights at initialization step (maybe not relevant to do so if any adaptive time stepping procedure is ever implemented).
-- Add time indexes (4 levels) to barotropic instantaneous arrays (AB3-AM4 time stepping)
+- Set initialization of filtering weights at initialization step (maybe not relevant to do so if any adaptive time stepping procedure is ever implemented - one would like to change the number of barotropic iterations  online).
+- Add time indexes (4 levels) to barotropic instantaneous arrays (AB3-AM4 time stepping) to match baroclinic mode syntax
+- We agreed (with Gurvan) to keep the barotropic filtering option (ln_bt_ave=T) even if it complicates a bit the integration. It will be useful for comparison with Demange's diffusive time stepping approach.
 
 2) Refactorize dynspg_ts module:
@@ -30 +31 @@
 - Same for barotropic to baroclinic forcing term: prep_stp_2D
 
+The second part should ease a possible transition to the coupling at each barotropic time step. The philosophy behind this is to be able to insert the external loop within the main time stepping routine and possibly cycle the stp routine over nstep x icycle steps, i.e. the total number of sub-steps. The integration of agrif should then be trivial, swapping grids at each parent sub cycle.
 
+Even if this task won't go up the AGRIF implementation itself, the idea is to have the following flowchart at the end:
 {{{
-! Set barotropic forcing (incl. 3d to 2d forcing)
-! Initialize instantaneous barotropic arrays
-CALL prep_stp_2D( kstp, Nbb, Nbb, Naa, Nrhs )
-
-DO kstp_e = 1, icycle
-   CALL stp_2D(kstp, kstp_e, ll_init, Nbbb_e, Nbb_e, Nnn_e, uu_e, vv_e, ssh_e, Naa_e)
-   ! Swap external arrays:
-   Nbbb_e =  Nbb_e
-   Nbb_e  =  Nnn_e
-   Nnn_e  =  Naa_e   
+DO WHILE( istp <= nitend  )
+   DO iit = 1, icycle
+      CALL stp   
+           | 
+           kstp = nit000 + MOD(Agrif_Nb_Step(), icycle)                   ! internal mode time step
+           kit = Agrif_Nb_Step() - icycle * MOD(Agrif_Nb_Step(), icycle)  ! external mode time step
+           |
+           do_bef_stp2D = (kit == 1)
+           do_aft_stp2D = (kit == icycle)                
+           |
+           IF ( do_bef_stp2D ) THEN
+              ! ... do stuff
+              ! Set barotropic forcing (incl. 3d to 2d forcing)
+              !  and initialize instantaneous barotropic arrays
+              CALL prep_stp_2D( kstp, Nbb, Nbb, Naa, Nrhs )
+           END IF
+           |
+           CALL stp_2D(kstp, kit, ll_init, Nbbb_e, Nbb_e, Nnn_e, uu_e, vv_e, ssh_e, Naa_e)
+           ! Swap external mode arrays:
+           Nbbb_e =  Nbb_e
+           Nbb_e  =  Nnn_e
+           Nnn_e  =  Naa_e
+           |
+           IF ( do_aft_stp2D ) THEN
+              ! ... do stuff
+           END IF 
+           |
+           CALL Agrif_Integrate_ChildGrids( stp ) 
+           |
+   END DO
+   istp = istp + 1
 END DO
 }}}