Changes between Initial Version and Version 1 of PDAF_diag_stddev

Timestamp:

Mar 21, 2025, 2:50:07 PM (12 days ago)

Author:

lnerger

Comment:

--

PDAF_diag_stddev

@@ +1 @@
+= PDAF_diag_stddev = 
+
+This page documents the routine `PDAF_diag_stddev` of PDAF, which was introduced with PDAF V3.0.
+
+This routine computes mean ensemble standard deviation taking into account domain-decomposition for parallelized models.
+
+The routine can be called in the pre/poststep routine of PDAF both before and after the analysis step to compute the ensemble statistics. This variant computes the standard deviation for the provided ensemble over the full decomposed domain of a parallel model. The variant without parallelization is [wiki:PDAF_diag_stddev_nompi].
+
+The interface is the following: 
+{{{
+SUBROUTINE PDAF_diag_stddev(dim, dim_ens, &
+     state, ens, stddev, do_mean, COMM_filter, status)
+}}}
+with the following arguments:
+{{{
+  INTEGER, INTENT(in) :: dim_p                 ! process-local state dimension
+  INTEGER, INTENT(in) :: dim_ens               ! Ensemble size
+  REAL, INTENT(inout) :: state_p(dim_p)        ! process-local state vector
+  REAL, INTENT(in)    :: ens_p(dim_p, dim_ens) ! process-local state ensemble
+  REAL, INTENT(out)   :: stddev_g              ! Global mean standard deviation of ensemble
+  INTEGER, INTENT(in) :: do_mean               ! Whether to compute ensemble mean
+  INTEGER, INTENT(in) :: COMM_filter           ! Filter communicator
+  INTEGER, INTENT(out) :: status               ! Status flag (0=success)
+}}}
+
+**Note:**
+ * The ensemble standard deviation is a common measure of the estimate model root mean square error. It is typically computed in `prepoststep_pdaf` to monitor the assimilation process.