Changes between Version 7 and Version 8 of ImplementationConceptOffline

Timestamp:

May 18, 2011, 4:36:30 PM (14 years ago)

Author:

lnerger

Comment:

--

ImplementationConceptOffline

@@ -27 +27 @@
 The structure of the assimilation program is the following:
  * At the beginning of the program, the routine `init_parallel_pdaf` is executed. `init_parallel_pdaf` creates the parallel environment for PDAF. In the offline mode, it is possible to execute the assimilation program on a single processor, even if the model is parallelized. 
- * Subsequently, a routine `init_pdaf` is executed. In this routine, parameters for PDAF can be defined and then the core initialization routine PDAF_init is called. This core routine also initializes the array of ensemble states. In case of the offline mode, this means that the ensemble is read from the output files of the model.
+ * Subsequently, a routine `init_pdaf` is executed. In this routine, parameters for PDAF can be defined and then the core initialization routine `PDAF_init` is called. This core routine also initializes the array of ensemble states. In case of the offline mode, this means that the ensemble is read from the output files of the model.
  * Finally, the PDAF core routine `PDAF_put_state` is executed. As for the offline mode there is no ensemble integration in the assimilation program, this subroutine directly computes the analysis step (i.e. the actual assimilation of the observations). In a user-supplied subroutine of `PDAF_put_state`, the ensemble of analysis states is finally written into restart files for the next forecast phase conducted by direct model integrations initialized from these files.
 
@@ -36 +36 @@
  * With regard to the parallelization, the assimilation program can be run on a single processor, i.e. without parallelization. The variables for the parallelization still have to be initialized by a call to `init_parallel_pdaf`. However, one does not need to compile with an MPI library, but it is sufficient to use the dummy implementation of the MPI-routines that is supplied with PDAF. If the model is parallelized, one need to ensure that the model fields are read correctly. In particular is in the parallel model each process write a separate files, one has to read these files sequentially in order to initialize an ensemble array holding the global state information.
  * For large-scale models, it can be useful to execute the assimilation program with parallelization. Perhaps, following the domain decomposition of the model is the easiest strategy for this. In this case the decomposition information from the model has to be read into the assimilation program in order to initialize the state dimension of the sub-domains as well as the coordinates for each sub-domain.
+ * The core routines of PDAF (those with the prefix `PDAF_`) are identical for the online and offline modes. The offline mode is switched on by selecting the corresponding subtype of the filter method in the call to `PDAF_init`.