= PDAFomi_diag_get_HXmean = 

This page documents the routine `PDAFomi_diag_get_HXmean` of PDAF, which was introduced with PDAF V3.0. This is part of the PDAF-OMI observation diagnostics module. 

The routine returns a pointer to a vector of the observed ensemble mean for the specified observation type (`id_obs`)..

Usually all PDAFomi_diag routines are called in `prepoststep_pdaf` where the observation information can be retrieved and analyzed.

The interface is the following: 
{{{
  SUBROUTINE PDAFomi_diag_get_HXmean(id_obs, dim_obs_diag, HXmean_p_ptr)
}}}
with the following arguments:
{{{
    INTEGER, INTENT(in) :: id_obs                    !< Index of observation type to return
    INTEGER, INTENT(out) :: dim_obs_diag             !< Observation dimension
    REAL, POINTER, INTENT(out) :: HXmean_p_ptr(:)    !< Pointer to observed ensemble mean
}}}

**Notes:**
 * In case of a parallelized model, the vector HXmean_p_prt contains the observed ensemble mean for the process-sub-domain
 * In Fortran user code the obsevation pointer should be declared in the form[[BR]] `REAL, POINTER :: HXmean_p_ptr(:)`[[BR]] It does not need to be allocated
 * If the observation diagnostics have not be activated by using [wiki:PDAFomi_set_obs_diag] the pointer will not be set and `dim_obs_diag=0` will be returned. This value can be checked before assessing the pointer array