PDAF_lseik_init.F90 Source File


Source Code

! Copyright (c) 2004-2024 Lars Nerger
!
! This file is part of PDAF.
!
! PDAF is free software: you can redistribute it and/or modify
! it under the terms of the GNU Lesser General Public License
! as published by the Free Software Foundation, either version
! 3 of the License, or (at your option) any later version.
!
! PDAF is distributed in the hope that it will be useful,
! but WITHOUT ANY WARRANTY; without even the implied warranty of
! MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
! GNU Lesser General Public License for more details.
!
! You should have received a copy of the GNU Lesser General Public
! License along with PDAF.  If not, see <http://www.gnu.org/licenses/>.
!
!$Id$
!BOP
!
! !ROUTINE: PDAF_lseik_init --- PDAF-internal initialization of LSEIK filter
!
! !INTERFACE:
SUBROUTINE PDAF_lseik_init(subtype, param_int, dim_pint, param_real, dim_preal, &
     ensemblefilter, fixedbasis, verbose, outflag)

! !DESCRIPTION:
! Initialization of LSEIK within PDAF. Performed are:\\
!   - initialize filter-specific parameters\\
!   - print screen information on filter configuration.
!
! !  This is a core routine of PDAF and
!    should not be changed by the user   !
!
! !REVISION HISTORY:
! 2003-08 - Lars Nerger - Initial code
! Later revisions - see svn log
!
! !USES:
  USE PDAF_mod_filter, &
       ONLY: incremental, Nm1vsN, dim_ens, rank, forget, &
       localfilter, type_forget, type_trans, type_sqrt

  IMPLICIT NONE

! !ARGUMENTS:
  INTEGER, INTENT(inout) :: subtype             ! Sub-type of filter
  INTEGER, INTENT(in) :: dim_pint               ! Number of integer parameters
  INTEGER, INTENT(inout) :: param_int(dim_pint) ! Integer parameter array
  INTEGER, INTENT(in) :: dim_preal              ! Number of real parameters 
  REAL, INTENT(inout) :: param_real(dim_preal)  ! Real parameter array
  LOGICAL, INTENT(out) :: ensemblefilter ! Is the chosen filter ensemble-based?
  LOGICAL, INTENT(out) :: fixedbasis     ! Does the filter run with fixed error-space basis?
  INTEGER, INTENT(in) :: verbose                ! Control screen output
  INTEGER, INTENT(inout):: outflag              ! Status flag

! !CALLING SEQUENCE:
! Called by: PDAF_init_filters
!EOP

! *** local variables ***
  REAL :: param_real_dummy    ! Dummy variable to avoid compiler warning


! ****************************
! *** INITIALIZE VARIABLES ***
! ****************************

  ! Initialize variable to prevent compiler warning
  param_real_dummy = param_real(1)

  ! Whether incremental updating is performed
  if (dim_pint>=4) THEN
     incremental = param_int(4)
     IF (param_int(4) /= 0 .AND. param_int(4) /= 1) THEN
        WRITE (*,'(/5x, a/)') &
             'PDAF-ERROR(10): Invalid setting for incremental updating!'
        outflag = 10
     END IF
  END IF

  ! Flag which definition of P is used for the SEIK filter
  ! (0): Factor N^-1; (1): Factor (N-1)^-1 - Recommended is 1 for 
  ! a real ensemble filter, 0 is for compatibility with older PDAF versions
  Nm1vsN = 1

  ! Rank of initial covariance matrix
  rank = dim_ens - 1

  ! Store type for forgetting factor
  IF (dim_pint >= 5) THEN
     type_forget = param_int(5)
  END IF

  ! Type of ensemble transformation
  IF (dim_pint >= 6) THEN     
     type_trans = param_int(6)
  END IF

  ! Store type of transform matrix square-root (only subtype=4)
  IF (dim_pint >= 7) THEN
     type_sqrt = param_int(7)
     IF (subtype==3) type_sqrt=1  ! For fixed covariance matrix alsways use Cholesky
  ELSE
     ! Default is Cholesky square-root
     type_sqrt = 1
  END IF

  ! Define whether filter is mode-based or ensemble-based
  ensemblefilter = .TRUE.

  ! Define whether filter is domain localized
  localfilter = 1

  ! Initialize flag for fixed-basis filters
  IF (subtype == 2 .OR. subtype == 3) THEN
     fixedbasis = .TRUE.
  ELSE
     fixedbasis = .FALSE.
  END IF


! *********************
! *** Screen output ***
! *********************

  filter_pe2: IF (verbose == 1) THEN
  
     WRITE(*, '(/a, 4x, a)') 'PDAF' ,'+++++++++++++++++++++++++++++++++++++++++++++++++++++++'
     WRITE(*, '(a, 4x, a)')  'PDAF' ,'+++                  LSEIK Filter                   +++'
     WRITE(*, '(a, 4x, a)')  'PDAF' ,'+++                                                 +++'
     WRITE(*, '(a, 4x, a)')  'PDAF' ,'+++        Domain-localized SEIK filter by          +++'
     WRITE(*, '(a, 4x, a)')  'PDAF' ,'+++   Nerger et al., Ocean Dynamics 56 (2006) 634   +++'
     WRITE(*, '(a, 4x, a)')  'PDAF' ,'+++      based in the global SEIK filter by         +++'
     WRITE(*, '(a, 4x, a)')  'PDAF' ,'+++ Pham et al., C. R. Acad. Sci. II, 326(1998) 255 +++'
     WRITE(*, '(a, 4x, a)')  'PDAF' ,'+++    and Pham, Mon. Wea. Rev. 129 (2001) 1194     +++'
     WRITE(*, '(a, 4x, a)')  'PDAF' ,'+++++++++++++++++++++++++++++++++++++++++++++++++++++++'

     ! *** General output ***
     WRITE (*, '(/a, 4x, a)') 'PDAF' ,'LSEIK configuration'
     WRITE (*, '(a, 10x, a, i1)') 'PDAF' ,'filter sub-type = ', subtype
     IF (subtype == 0) THEN
        WRITE (*, '(a, 12x, a)') 'PDAF' ,'--> Standard LSEIK'
     ELSE IF (subtype == 2) THEN
        WRITE (*, '(a, 12x, a)') 'PDAF' ,'--> fixed error-space basis'
     ELSE IF (subtype == 3) THEN
        WRITE (*, '(a, 12x, a)') 'PDAF' ,'--> fixed state covariance matrix'
     ELSE IF (subtype == 4) THEN
        WRITE (*, '(a, 12x, a)') 'PDAF' ,'--> SEIK with ensemble transformation'
     ELSE IF (subtype == 5) THEN
        WRITE (*, '(a, 12x, a)') 'PDAF' ,'--> offline mode'

        ! Reset subtype
        subtype = 0
     ELSE
        WRITE (*, '(/5x, a/)') 'PDAF-ERROR(2): No valid sub type!'
        outflag = 2
     END IF
     IF (type_trans == 0) THEN
        WRITE (*, '(a, 12x, a)') 'PDAF' ,'--> Transform ensemble with deterministic Omega'
     ELSE IF (type_trans == 1) THEN
        WRITE (*, '(a, 12x, a)') 'PDAF' ,'--> Transform ensemble with random orthonormal Omega'
     ELSE IF (type_trans == 2) THEN
        WRITE (*, '(a, 12x, a)') 'PDAF' ,'--> Transform ensemble with product Omega'
     ELSE
        WRITE (*,'(/5x, a/)') &
             'PDAF-ERROR(9): Invalid setting for ensemble transformation!'
        outflag = 9
     END IF
     IF (incremental == 1) &
          WRITE (*, '(a, 12x, a)') 'PDAF' ,'--> Perform incremental updating'
     IF (type_forget == 0) THEN
        WRITE (*, '(a, 12x, a, f5.2)') 'PDAF' ,'--> Use fixed forgetting factor:', forget
     ELSEIF (type_forget == 1) THEN
        WRITE (*, '(a, 12x, a)') 'PDAF' ,'--> Use global adaptive forgetting factor'
     ELSEIF (type_forget == 2) THEN
        WRITE (*, '(a, 12x, a)') 'PDAF' ,'--> Use local adaptive forgetting factors'
     ELSE
        WRITE (*, '(/5x, a/)') 'PDAF-ERROR(8): Invalid type of forgetting factor!'
        outflag = 8
     ENDIF
     WRITE (*, '(a, 12x, a, i5)') 'PDAF' ,'--> ensemble size:', dim_ens

  END IF filter_pe2

END SUBROUTINE PDAF_lseik_init