= PDAF_localfilter = 

This page documents the function `PDAF_get_localfilter` of PDAF, which are introduced with PDAF 3.0.

The function is an altenative to the routine [wiki:PDAF_get_localfilter].

The function returns the information whether the chosen filter is a domain-localized filter (LESTKF, LETKF, LSEIK, LNETF). It can be called in assimilate_pdaf.F90 to control whether to call either PDAF3_assimilate_global or PDAF3_assimilate_local (or PDAF3_put_state_global or PDAF3_put_state_local).

The routine is typically called in the model code in assimilate_pdaf. The function can only be used if PDAF was initialized before by a call to `PDAF_init`.

The interface is the following:
{{{
  INTEGER FUNCTION PDAF_localfilter()
}}}
without arguments. The return value is
 * 0: global filter
 * 1: local filter

The return value can be directly used, e.g. as
{{{
  IF (PDAF_localfilter() == 1) THEN
    CALL PDAF3_assimilate_local(...)
  ELSE
    CALL PDAF3_assimilate_global(...)
  ENDIF
}}}

**Notes:**
 * The difference between the return values 0 and 1 is mainly the way how PDAF-OMI handles observations. 
 * For the ENSRF/EAKF, PDAF_localfilter() also returns the value 1. This is because the observation handling for the ENSRF/EAKF uses the same approach as for domain-localized filters