= 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. This relates to Fortran code.

* Include[[BR]] `USE PDAF`[[BR]] 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 your Makefile to include[[BR]]`-IPATH_TO_PDAF_INCLUDE`,[[BR]] 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 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, e.g. 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 [wiki: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 [wiki:PDAF_assimilate_lnetf] or [wiki:PDAF_put_state_lnetf])
  * Of your code used the SEEK filter: This filter was deprecated for a longer time and is no longer available with PDAF V3.0. Any call to e.g. PDAF_assimilate_seek has to be removed.

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




* New general module 'PDAF' replacing the optional module 'PDAF_interface
* The subtypes have been renumbered: subtypes 0 and 1 are unchanged, the other dynamic subtypes are changed as 4=>2, 6=>3, 7=>4; the variant with fixed ensmeble are changed as 2=>10, 3=>11. 
* Changes in the index value a some parameters: The index of some of the parameters set in PDAF_init has changed for better overall consistency. (See .... for an overview of the parameters)
* The SEEK filter (filtertype=0) was finally removed after it was marked deprecated for a longer period.
* Removed 'src/Makefile'. Now only the new Makefile in the main directory exists. However, if one has a workflow basing on src/Makefile and can copy the Makefile and adapt it according to the description within the file.
* The 'simplified interface' (routine names ending with `_si`) has been removed.

- additional parameter in PDAF_assimilate_lnetf and PDAF_put_state_lnetf
- porting from PDAFomi to PDAF3 for global filters: Just change the name of the routine
- porting from PDAFlocalomi to PDAF3 for local filters: Just change the name of the routine
- porting from PDAFomi to PDAF3 for local filters: The PDAF3 interface uses PDAFlocal so that the routines g2l_state_pdaf and l2g_state_pdaf are not present. Follow the implementation guide for init_dim_l to initialize the information for PDAFlocal
- porting from classical PDAF interface with fully specification of all call-back routines: See implementation guide (PDAF3 uses both PDAF-OMI and PDAF-local to provide compact interfaces)
- porting from PDAFomi or PDAFlocalomi for 3D-Var: Change the name of the routine
- check subtype: 0 and 1 are unchanged; for others: 2=>10, 3=>11, 4=>2, 6=>3, 7=>4
- the option to run the offline mode as 'subtype=5' was removed. It is now require to call "PDAF_set_offline_mode"