Porting from PDAF2 to PDAF3

PDAF V3.0 is not fully backward compatible with PDAF2. Modernizing the PDAF code motivated us to allow some changes which require code changes by the PDAF users. Thus, when switching from using PDAF2 to PDAF3, it is not possible to just compile the new PDAF library and link it with your code (in contrast to many previous releases).

Here we explain the steps required to adapt your code to PDAF 3.

Using PDAF3 with existing codes

To use existing assimilation code, we recommend the following steps. This relates for Fortran code.

• Include
  USE PDAF
  in all routines that call PDAF routines (e.g. in init_pdaf and assimilate_pdaf).
• If you used USE PDAF_interface_module in your code, replace this by USE PDAF.
• You might need to adapt the Makefile of your program to include
  -IPATH_TO_PDAF_INCLUDE,
  where PATH_TO_PDAF_INCLUDE is the directory include/ of your PDAF installation. The compiler needs to find the PDAF module files which are places in include/
• particular cases:
  • If the compile process of your programm includes the compilation of PDAF using src/Makefile: With PDAF3 the Makefile is now only in the base-directory and there is no Makefile any more in src/. Thus, addapt to use the Makefile in the base-directory (alternatively you can copy this Makefile into src/ and adapt it according to the hints given inside the Makefile
  • If you used the offline mode by specifying subtype=5: change subtype to 0 and add a call to the routine PDAF_set_offline_mode in init_pdaf. (see, the example in the file tutorial/offline_2D_serial/init_pdaf_offline.F90 where the call to PDAF_set_offline_mode is at the very end of the routine; see also OfflineInitPdaf).
  • If your code calls PDAF_assimilate_lnetf or PDAF_put_state_lnetf: There was an argument added for init_obs_pdaf. the code has to be adapted for this additional arguments. (see PDAF_assimilate_lnetf or PDAF_put_state_lnetf)
  • If your code used the SEEK filter: This filter was deprecated for a longer time and is no longer available with PDAF V30. Any call to e.g. PDAF_assimilate_seek has to be removed.
  • If your code used the 'simplified interface', i.e. routines with ending _si: The _si routine are no longer present in PDAF V3.0. Instead use the full interface routine, i.e. the routine with the same name as the _si routine, but without _si. Then set the arguments to the names that you find inside the _si routine file from PDAF2.

With these adaptions, the compiling the program should be possible.

Two additional changes relate to the specification of subtype and the integer and real parameters for PDAF_init:

• A few of the parameters used to configure PDAF in the call to PDAF_init have changed their index. This only concerns the EnKF, LEnKF, LKNETF and PF. An overview of the parameters is show in the tables on the page 'Available options for the different DA methods'.
• The values of subtype have been renumbered as follows

old subtype PDAF2	new subtype PDAF3
0	0 (no change)
1	1 (no change)
2	10
3	11
4	2
5	5 (no longer offline mode)
6	3
7	4

Porting to the PDAF3 interface

PDAF V3.0 also provides a set of new routines to call the analysis step, which we call the PDAF3 interface, because the calls are of the format PDAF3_assimilate_ or PDAF3_put_state_. It is not required to switch to these new interface routines, but generally recommended.

Details about the PDAF3 interface are provided on the Page on the PDAF3 interface.

Using new features of PDAF V3.0

PDAF V3.0 also introduces several new features. An overview of these is given on the Page on new functionality on PDAF V3.0.