Changes between Initial Version and Version 1 of obs_op_lin_pdaf

Timestamp:

Dec 9, 2021, 3:17:14 PM (4 years ago)

Author:

lnerger

Comment:

--

obs_op_lin_pdaf

@@ +1 @@
+= obs_op_lin_pdaf = 
+
+The page document the user-supplied call-back routine `obs_op_lin_pdaf`.
+
+The routine `obs_op_lin_pdaf` (`U_obs_op_lin` inside PDAF) is a call-back routine that has to be provided by the user. 
+
+The routine is used with the all 3D-Var methods. It has to perform the operation of the linearized observation operator acting on a state vector increment that is provided as `state_p`. The observed state has to be returned in `m_state_p`.
+
+The interface is the following:
+{{{
+SUBROUTINE obs_op_lin_pdaf(step, dim_p, dim_obs_p, state_p, m_state_p)
+
+  INTEGER, INTENT(in) :: step               ! Current time step
+  INTEGER, INTENT(in) :: dim_p              ! PE-local dimension of state
+  INTEGER, INTENT(in) :: dim_obs_p          ! Dimension of observed state
+  REAL, INTENT(in)    :: state_p(dim_p)     ! PE-local model state
+  REAL, INTENT(out) :: m_state_p(dim_obs_p) ! PE-local observed state
+}}}
+
+The routine is called during the analysis step. It has to perform the operation of the linearized observation operator acting on a state vector increment that is provided as `state_p`. The observed state has to be returned in `m_state_p`.
+
+Hints:
+ * For a model using domain decomposition, the operation is on the PE-local sub-domain of the model and has to provide the observed sub-state for the PE-local domain.
+ * If the observation operator involves a global operation, e.g. some global integration, while using domain-decomposition one has to gather the information from the other model domains using MPI communication.