= PDAF_init_si = This page documents the routine `PDAF_init_si` of PDAF. `PDAF_init_si` is the variant of [wiki:PDAF_init PDAF_init] with the [PdafSimplifiedInterface simplified interface]. The difference between both routines is that in the simplified interface the names of the call-back subroutines are not specified. Instead the routine assumes that the call-back routines have a standard name as specified at the end of this page. The routine `PDAF_init` is typically called in `init_pdaf` where also the variables for the call are set. The call to `PDAF_init_si` has the following structure: {{{ CALL PDAF_init(filtertype, subtype, step_null, & filter_param_i, length_filter_param_i, & filter_param_r, length_filter_param_r, & COMM_model, COMM_filter, COMM_couple, & task_id, n_modeltasks, filterpe, & screen, status_pdaf) }}} The required variables are the following: * `filtertype`: An integer defining the type of filter algorithm. Available are * 0: SEEK * 1: SEIK * 2: EnKF * 3: LSEIK * 4: ETKF * 5: LETKF * 6: ESTKF * 7: LESTKF * 8: LEnKF * 9: NETF * 10: LNETF * 12: PF * 100: GENOBS (generate synthetic observations) * 200: 3D-Var * `subtype`: An integer defining the sub-type of the filter algorithm (see the example code in `templates/online_omi/init_pdaf.F90` for choices). * If `PDAF_init` is called with `subtype=-1` the available options are shown for the selected filter algorithm. * `step_null`: An integer defining the initial time step. For some cases it can use useful to set `step_null` larger to 0. * `filter_param_i`: Integer array collecting several variables for PDAF. The first two variables are mandatory and equal for all filters. Further variables are optional (see example code or use `subtype=-1` to display available options.). The mandatory variables are in the following order: * The size of the local state vector for the current process. * The ensemble size for all ensemble-based filters (or the rank of the state covariance matrix for mode-based filters like SEEK) * `length_filter_param_i`: An Integer defining the length of the array `filter_param_i`. The entries in the array are parsed up to this index. * `filter_param_r`: Array of reals collecting floating point variables for PDAF. The first variable is mandatory and equal for all filters. Further variables are optional (see example code in `templates/online_omi/init_pdaf.F90` or use `subtype=-1` to display available options.). The mandatory variable is: * The value of the forgetting factor controlling covariance inflation (required to be larger than zero; common are values between 0.9 and 1.0. For 1.0 the ensemble is not inflated.) * `length_filter_param_r`: An Integer defining the length of the array `filter_param_r`. The entries in the array are parsed up to this index. * `COMM_model`: The communicator variable `COMM_model` as initialized by `init_parallel_pdaf`. (Usually stored in the module `mod_assimilation`) * `COMM_filter`: The communicator variable `COMM_filter` as initialized by `init_parallel_pdaf`. (Usually stored in the module `mod_assimilation`) * `COMM_couple`: The communicator variable `COMM_couple` as initialized by `init_parallel_pdaf`. (Usually stored in the module `mod_assimilation`) * `task_id`: The index of the model tasks as initialized by `init_parallel_pdaf`. (Usually stored in the module `mod_assimilation`) * `n_modeltasks`: The number of model tasks as defined before the call to `init_parallel_pdaf`. (Usually stored in the module `mod_assimilation`) * `filterpe`: A logical flag showing whether a process belongs to `COMM_filter` as initialized by `init_parallel_pdaf`. (Usually stored in the module `mod_assimilation`) * `screen`: An integer defining whether information output is written to the screen (i.e. standard output). The following choices are available: * 0: quiet mode - no information is displayed. * 1: Display standard information (recommended) * 2: as 1 plus display of timing information during the assimilation process * `status_pdaf`: An integer used as status flag of PDAF. If `status_pdaf` is zero upon exit from `PDAF_init` the initialization was successful. An error occurred for non-zero values. (The error codes are documented in the routine `PDAF_init`.) An overview of available options for each filter an be found on the [wiki:AvailableOptionsforInitPDAF overview page on options]. It is recommended that the value of `status_pdaf` is checked in the program after `PDAF_init_si` is executed. Only if its value is 0 the initialization was successful. The routine `PDAF_init_si` calls the user-defined call-back routine for the initialization of the ensemble array. The name of this user-supplied routine `init_ens_pdaf`. An overview of the pre-defined names is provided in the [PdafSimplifiedInterface documentation of PDAF's simplified interface]. For the specification of the routine `init_ens_pdaf` see: '[InitPdaf#User-suppliedroutineU_init_ensinit_ens_pdaf.F90 User-supplied routine U_init_ens]'