Changes between Initial Version and Version 1 of AvailableOptionsforInitPDAFuntilPDAF231

Timestamp:

Mar 20, 2025, 7:12:09 PM (13 days ago)

Author:

lnerger

Comment:

--

AvailableOptionsforInitPDAFuntilPDAF231

@@ +1 @@
+= Available options for the different filter algorithms =
+
+
+[[PageOutline(2-3,Contents of this page)]]
+
+There are different operations for each of the filter algorithms that need to be specified in the call to `PDAF_init`. To display the available options in a compiled assimilation program, one can use run with the specification `subtype=-1`. In this case `PDAF_init` wil display the available options for the selected filter algorithm and exit with an error status of -1.
+
+Below we list the options as they are displayed using `subtype=-1`.
+
+
+== SEIK (filtertype=1) ==
+
+{{{
+PDAF     Available options for SEIK:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: full ensemble integration; left-sided application of T
+PDAF       1: full ensemble integration; right-sided application of T
+PDAF       2: Fixed error space basis
+PDAF       3: Fixed state covariance matrix
+PDAF       4: Implementation with explicit ensemble transformation
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): not used
+PDAF       param_int(4): Apply incremental updating; optional
+PDAF           0: no incremental updating (default)
+PDAF           1: apply incremental updating
+PDAF       param_int(5): Type of forgetting factor; optional
+PDAF           0: fixed forgetting factor (default)
+PDAF           1: adaptive forgetting factor (experimental)
+PDAF       param_int(6): Type of ensemble transformation matrix; optional
+PDAF           0: deterministic omega (default)
+PDAF           1: random orthonormal omega orthogonal to (1,...,1)^T
+PDAF           2: use product of 0 with random orthonomal matrix with eigenvector (1,...,1)^T
+PDAF              (experimental; for random transformations, 1 is recommended)
+PDAF       param_int(7): Type of transformation matrix square root; optional
+PDAF           (Only relevant for subtype/=3)
+PDAF           0: symmetric square root (default)
+PDAF           1: Cholesky decomposition
+PDAF       param_int(8): Application of observation operator H, optional
+PDAF           0: Apply H to ensemble mean to compute residual (default)
+PDAF           1: Apply H to all ensemble states and then compute residual from mean of these
+PDAF              param_int(8)=1 is the recomended choice for nonlinear H
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           >=1 for subtypes 0 and 1; not larger than total number of processors
+PDAF           =1 required for subtypes 2 and 3
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     --- Internal parameter (defined inside PDAF) ---
+PDAF       Nm1vsN: Normalization of covariance matrix; default: 1
+PDAF           0: normalization with 1/(Ensemble size)
+PDAF              (original SEIK, mainly for compatibility with older studies)
+PDAF           1: normalization with 1/(Ensemble size - 1)
+PDAF           (sample covariance matrix consistent with other EnKFs)
+PDAF     +++++++++ End of option overview for the SEIK filter ++++++++++
+}}}
+
+
+== EnKF (filtertype=2) ==
+
+{{{
+PDAF     Available options for EnKF:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: Full ensemble integration; analysis for 2*dim_obs>dim_ens
+PDAF       1: Full ensemble integration; analysis for 2*dim_obs<=dim_ens
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): maximum rank for inversion of HPH^T, optional, default=0
+PDAF           (for =0, HPH is inverted by solving the representer equation)
+PDAF           (if set to >=ensemble size, it is reset to ensemble size - 1)
+PDAF       param_int(4): not used
+PDAF       param_int(5): Size of smoothing lag (>=0), optional
+PDAF           0: no smoothing (default)
+PDAF           >0: apply smoother up to specified lag
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           (>=1; not larger than total number of processors)
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     +++++++++ End of option overview for the EnKF ++++++++++
+}}}
+
+
+== LSEIK (filtertype=3) ==
+
+{{{
+PDAF     Available options for LSEIK:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: full ensemble integration; left-sided application of T
+PDAF       2: Fixed error space basis
+PDAF       3: Fixed state covariance matrix
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): not used
+PDAF       param_int(4): Apply incremental updating; optional
+PDAF           0: no incremental updating (default)
+PDAF           1: apply incremental updating
+PDAF       param_int(5): Type of forgetting factor; optional
+PDAF           0: fixed forgetting factor (default)
+PDAF           1: adaptive forgetting factor for full domain (experimental)
+PDAF           2: locally adaptive forgetting factor (experimental)
+PDAF       param_int(6): Type of ensemble transformation matrix; optional
+PDAF           0: deterministic omega (default)
+PDAF           1: random orthonormal omega orthogonal to (1,...,1)^T
+PDAF           2: use product of 0 with random orthonomal matrix with eigenvector (1,...,1)^T
+PDAF              (experimental; for random transformations, 1 is recommended)
+PDAF       param_int(7): Type of transformation matrix square root; optional
+PDAF           (Only relevant for subtype/=3)
+PDAF           0: symmetric square root (default)
+PDAF           1: Cholesky decomposition
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           >=1 for subtypes 0 and 1; not larger than total number of processors
+PDAF           =1 required for subtypes 2 and 3
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     --- Internal parameter (defined inside PDAF) ---
+PDAF       Nm1vsN: Normalization of covariance matrix; default: 1
+PDAF           0: normalization with 1/(Ensemble size)
+PDAF              (original SEIK, mainly for compatibility with older studies)
+PDAF           1: normalization with 1/(Ensemble size - 1)
+PDAF              (sample covariance matrix consistent with other EnKFs)
+PDAF     +++++++++ End of option overview for the LSEIK filter ++++++++++
+}}}
+
+
+== ETKF (filtertype=4) ==
+
+{{{
+PDAF     Available options for ETKF:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: full ensemble integration; apply T-matrix analogously to SEIK
+PDAF       1: full ensemble integration; formulation without T matrix
+PDAF       2: Fixed error space basis; analysis with T-matrix
+PDAF       3: Fixed state covariance matrix; analysis with T-matrix
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): Size of smoothing lag (>=0), optional
+PDAF           0: no smoothing (default)
+PDAF           >0: apply smoother up to specified lag
+PDAF       param_int(4): not used
+PDAF       param_int(5): Type of forgetting factor; optional
+PDAF           0: fixed forgetting factor (default)
+PDAF           1: adaptive forgetting factor (experimental)
+PDAF       param_int(6): Type of ensemble transformation matrix; optional
+PDAF           0: deterministic transformation (default)
+PDAF           2: use product of 0 with random orthonomal matrix with eigenvector (1,...,1)^T
+PDAF       param_int(7): not used
+PDAF       param_int(8): Application of observation operator H
+PDAF           0: Apply H to ensemble mean to compute residual (default)
+PDAF           1: Apply H to all ensemble states; then compute residual from mean of these
+PDAF              param_int(8)=1 is the recomended choice for nonlinear H
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           >=1 for subtypes 0 and 1; not larger than total number of processors
+PDAF           =1 required for subtypes 2 and 3
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     +++++++++ End of option overview for the ETKF ++++++++++
+}}}
+
+
+== LETKF (filtertype=5) ==
+
+{{{
+PDAF     Available options for LETKF:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: full ensemble integration;  apply T-matrix analogously to SEIK
+PDAF       2: Fixed error space basis; analysis with T-matrix
+PDAF       3: Fixed state covariance matrix; analysis with T-matrix
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): Size of smoothing lag (>=0), optional
+PDAF           0: no smoothing (default)
+PDAF           >0: apply smoother up to specified lag
+PDAF       param_int(4): not used
+PDAF       param_int(5): Type of forgetting factor; optional
+PDAF           0: fixed forgetting factor (default)
+PDAF           1: adaptive forgetting factor for full domain (experimental)
+PDAF           2: locally adaptive forgetting factor (experimental)
+PDAF       param_int(6): Type of ensemble transformation matrix; optional
+PDAF           0: deterministic transformation (default)
+PDAF           2: use product of 0 with random orthonomal matrix with eigenvector (1,...,1)^T
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           >=1 for subtypes 0 and 1; not larger than total number of processors
+PDAF           =1 required for subtypes 2 and 3
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     +++++++++ End of option overview for the LETKF ++++++++++
+}}}
+
+
+== ESTKF (filtertype=6) ==
+
+{{{
+PDAF     Available options for ESTKF:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: Standard implementation with ensemble integration
+PDAF       2: Fixed error space basis
+PDAF       3: Fixed state covariance matrix
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): Size of smoothing lag (>=0), optional
+PDAF           0: no smoothing (default)
+PDAF           >0: apply smoother up to specified lag
+PDAF       param_int(4): not used
+PDAF       param_int(5): Type of forgetting factor; optional
+PDAF           0: fixed forgetting factor (default)
+PDAF           1: adaptive forgetting factor (experimental)
+PDAF       param_int(6): Type of ensemble transformation matrix; optional
+PDAF           0: deterministic omega (default)
+PDAF           1: random orthonormal omega orthogonal to (1,...,1)^T
+PDAF           2: use product of 0 with random orthonomal matrix with eigenvector (1,...,1)^T
+PDAF              (experimental; for random transformations, 0 or 1 are recommended)
+PDAF       param_int(7): Type of transformation matrix square root; optional
+PDAF           0: symmetric square root (default)
+PDAF           1: Cholesky decomposition
+PDAF       param_int(8): Application of observation operator H
+PDAF           0: Apply H to ensemble mean to compute residual (default)
+PDAF           1: Apply H to all ensemble states; then compute residual from mean of these
+PDAF              param_int(8)=1 is the recomended choice for nonlinear H
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           >=1 for subtypes 0 and 1; not larger than total number of processors
+PDAF           =1 required for subtypes 2 and 3
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     +++++++++ End of option overview for the ESTKF  ++++++++++
+}}}
+
+
+== LESTKF (filtertype=7) ==
+
+{{{
+PDAF     Available options for LESTKF:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: Standard implementation with ensemble integration
+PDAF       2: Fixed error space basis
+PDAF       3: Fixed state covariance matrix
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): Size of smoothing lag (>=0), optional
+PDAF           0: no smoothing (default)
+PDAF           >0: apply smoother up to specified lag
+PDAF       param_int(4): not used
+PDAF       param_int(5): Type of forgetting factor; optional
+PDAF           0: fixed forgetting factor (default)
+PDAF           1: adaptive forgetting factor for full domain (experimental)
+PDAF           2: locally adaptive forgetting factor (experimental)
+PDAF       param_int(6): Type of ensemble transformation matrix; optional
+PDAF           0: deterministic omega (default)
+PDAF           1: random orthonormal omega orthogonal to (1,...,1)^T
+PDAF           2: use product of 0 with random orthonomal matrix with eigenvector (1,...,1)^T
+PDAF              (experimental; for random transformations, 1 is recommended)
+PDAF       param_int(7): Type of transformation matrix square root; optional
+PDAF           0: symmetric square root (default)
+PDAF           1: Cholesky decomposition
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           >=1 for subtypes 0 and 1; not larger than total number of processors
+PDAF           =1 required for subtypes 2 and 3
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     +++++++++ End of option overview for the LESTKF ++++++++++
+}}}
+
+
+== LEnKF (filtertype=8) ==
+
+{{{
+PDAF     Available options for LEnKF:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: Full ensemble integration; analysis with covariance localization
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): maximum rank for inversion of HPH^T, optional, default=0
+PDAF           (for =0, HPH is inverted by solving the representer equation)
+PDAF           (if set to >=ensemble size, it is reset to ensemble size - 1)
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           (>=1; not larger than total number of processors)
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     +++++++++ End of option overview for the LEnKF ++++++++++
+}}}
+
+
+== NETF (filtertype=9) ==
+
+{{{
+PDAF     Available options for NETF:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: Standard implementation with ensemble integration
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): Size of smoothing lag (>=0), optional
+PDAF           0: no smoothing (default)
+PDAF           >0: apply smoother up to specified lag
+PDAF       param_int(4): Type of ensemble perturbations, optional
+PDAF           0: no perturbations (default)
+PDAF           1: constant standard deviation
+PDAF           2: relative to ensemble standard deviation
+PDAF       param_int(5): Type of forgetting factor; optional
+PDAF           0: forgetting factor on forecast ensemble (default)
+PDAF           2: forgetting factor on analysis ensemble
+PDAF       param_int(6): Type of ensemble transformation matrix; optional
+PDAF           0: random orthonormal matrix orthogonal to (1,...,1)^T (default)
+PDAF           1: deterministic transformation
+PDAF       param_int(7): Type of weights inflation; optional
+PDAF           0: no weights inflation (default)
+PDAF           1: inflate so that N_eff/N > param_real(2)
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required
+PDAF       param_real(2): Limit for weigts inflation N_eff/N > param_real(2), optional, default=0.0
+PDAF       param_real(3): Ensemble perturbation level (>0), required, only used if param_int(4)>0
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           >=1 for subtypes 0 and 1; not larger than total number of processors
+PDAF           =1 required for subtypes 2 and 3
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     +++++++++ End of option overview for the NETF  ++++++++++
+}}}
+
+== LNETF (filtertype=10) ==
+
+{{{
+PDAF     Available options for LNETF:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: Standard implementation with ensemble integration
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): Size of smoothing lag (>=0), optional
+PDAF           0: no smoothing (default)
+PDAF           >0: apply smoother up to specified lag
+PDAF       param_int(4): Type of ensemble perturbations, optional
+PDAF           0: no perturbations (default)
+PDAF           1: constant standard deviation
+PDAF           2: relative to ensemble standard deviation
+PDAF       param_int(5): Type of forgetting factor; optional
+PDAF           0: forgetting factor on forecast ensemble (default)
+PDAF           1: forgetting factor on forecast ensemble only observed domains
+PDAF           2: forgetting factor on analysis ensemble
+PDAF           3: forgetting factor on analysis ensemble only observed domains
+PDAF       param_int(6): Type of ensemble transformation matrix; optional
+PDAF           0: random orthonormal matrix orthogonal to (1,...,1)^T (default)
+PDAF           1: deterministic transformation
+PDAF       param_int(7): Type of weights inflation; optional
+PDAF           0: no weights inflation (default)
+PDAF           1: inflate so that N_eff/N > param_real(2)
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required
+PDAF       param_real(2): Limit for weigts inflation N_eff/N > param_real(2), optional, default=0.0
+PDAF       param_real(3): Ensemble perturbation level (>0), required, only used if param_int(4)>0
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           >=1 for subtypes 0 and 1; not larger than total number of processors
+PDAF           =1 required for subtypes 2 and 3
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     +++++++++ End of option overview for the LNETF  ++++++++++
+}}}
+
+
+== LKNETF (filtertype=11) ==
+
+Note: The LKNETF (hybrid local Kalman-nonlinear ensemble transform filter) was added in PDAF V2.1.
+
+{{{
+PDAF     Available options for LKNETF:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: HNK: 2-step LKNETF with NETF before LETKF
+PDAF       1: HKN: 2-step LKNETF with LETKF before NETF
+PDAF       4: HSync: LKNETF synchronous
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): not used
+PDAF       param_int(4): not used
+PDAF       param_int(5): Type of forgetting factor; optional
+PDAF           0: inflate forecast ensemble by 1/forget (default)
+PDAF           1: inflate forecast ensemble by 1/forget only observed domains
+PDAF           2: inflate analysis ensemble by 1/forget
+PDAF           3: inflate analysis ensemble by 1/forget only observed domains
+PDAF       param_int(6): Type of ensemble transformation matrix; optional
+PDAF           0: random orthonormal matrix orthogonal to (1,...,1)^T (default)
+PDAF           1: deterministic transformation
+PDAF       param_int(7): Type of hybrid weight; optional
+PDAF           0: fixed value
+PDAF           1: gamma_lin: (1 - N_eff/N_e)*param_real(2) (default)
+PDAF           2: gamma_alpha: hybrid weight from N_eff/N>=param_real(2)
+PDAF           3: gamma_ska: 1 - min(s,k)/sqrt(param_real(3)) with N_eff/N>=param_real(2)
+PDAF           4: gamma_sklin: 1 - min(s,k)/sqrt(param_real(3)) >= 1-N_eff/N>=param_real(2)
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required
+PDAF       param_real(2): prescribed hybrid weight gamma (usually >0 and <=1), optional, default=1.0
+PDAF       param_real(3): hybrid norm kappa (>0), optional, default=dim_ens
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           >=1 for subtypes 0 and 1; not larger than total number of processors
+PDAF           =1 required for subtypes 2 and 3
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     +++++++++ End of option overview for the LKNETF  ++++++++++
+}}}
+
+== PF (filtertype=12) ==
+
+{{{
+PDAF     Available options for PF:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: Standard implementation with ensemble integration
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): Resampling type, optional
+PDAF           1: probabilistic resamping (default)
+PDAF           2: stochastic universal resampling
+PDAF           3: residual resampling
+PDAF       param_int(4): Type of ensemble perturbations, optional
+PDAF           0: no perturbations (default)
+PDAF           1: constant standard deviation
+PDAF           2: relative to ensemble standard deviation
+PDAF       param_int(5): Type of forgetting factor; optional
+PDAF           0: forgetting factor on forecast ensemble (default)
+PDAF           2: forgetting factor on analysis ensemble
+PDAF       param_int(6): Type of weights inflation; optional
+PDAF           0: no weights inflation (default)
+PDAF           1: inflate so that N_eff/N > param_real(2)
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Ensemble pert. level (>0), required, only used if param_int(4)>0
+PDAF       param_real(2): Forgetting factor (usually >0 and <=1), optional, default=1.0
+PDAF       param_real(3): Limit for weigts inflation N_eff/N > param_real(2), optional, default=0.0
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           >=1 for subtypes 0 and 1; not larger than total number of processors
+PDAF           =1 required for subtypes 2 and 3
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     +++++++++ End of option overview for the PF  ++++++++++
+}}}
+
+== GENOBS (filtertype=100) ==
+
+Note: GENOBS used filtertype=11 before PDAF V2.0.
+
+{{{
+PDAF     Available options for GENOBS:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: Standard implementation with ensemble integration
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required, but not used
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           =1 for GENOBS; not larger than total number of processors
+PDAF           =1 required for subtypes 2 and 3
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     +++++++++ End of option overview for GENOBS  ++++++++++
+}}}
+
+== 3DVAR (filtertype=200) ==
+
+Note: 3D-Var methods were added in PDAF V2.0.
+
+{{{
+PDAF     Available options for 3D-Var:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: incremental 3D-Var with parameterized covariance matrix
+PDAF       1: 3D ensemble Var using LESTKF for ensemble transformation
+PDAF       4: 3D ensemble Var using ESTKF for ensemble transformation
+PDAF       6: hybrid 3D-Var using LESTKF for ensemble transformation
+PDAF       7: hybrid 3D-Var using ESTKF for ensemble transformation
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): Select optimization method (solver), required
+PDAF           0: LBFGS (default)
+PDAF           1: CG+
+PDAF           2: direct implementation of CG
+PDAF           3: direct implementation of CG with decomposed control vector
+PDAF       param_int(4): size of parameterized control vector (for parameterized and hybrid 3D-Var), required
+PDAF       param_int(5): size of ensemble control vector (required for ensemble and hybrid 3D-Var), 
+PDAF       param_int(6): Solver-specific parameter, optional
+PDAF           LBFGS: parameter m (default=5)
+PDAF                Number of corrections used in limited memory matrix; 3<=m<=20
+PDAF           CG+: parameter method (default=2)
+PDAF                (1) Fletcher-Reeves, (2) Polak-Ribiere, (3) positive Polak-Ribiere
+PDAF           CG: maximum number of iterations (default=200)
+PDAF       param_int(7): Solver-specific parameter, optional
+PDAF           CG+: parameter irest (default=1)
+PDAF                (0) no restarts; (n>0) restart every n steps
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required;
+PDAF           (only used for ensemble and hybrid 3D-Var)
+PDAF       param_real(2): hybrid weight beta, optional (only for hybrid 3D-Var)
+PDAF           range >=0.0 and <=1.0, =1.0 for pure ensemble 3D-var  (default=0.5)
+PDAF       param_real(3): Solver-specific parameter, optional
+PDAF           LBFGS: Limit for stopping iterations (pgtol, default=1.0e-5)
+PDAF           CG+: convergence parameter eps (default=1.0e-5)
+PDAF           CG: convergence parameter eps (default=1.0e-6)
+PDAF       param_real(4): Solver-specific parameter, optional
+PDAF           LBFGS: Tolerance in termination test (factr, default=1.0e+7)
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           >=1 for subtypes 0 and 1; not larger than total number of processors
+PDAF           =1 required for subtypes 2 and 3
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     +++++++++ End of option overview for 3DVAR ++++++++++
+}}}
+
+
+
+== SEEK (filtertype=0) ==
+
+**Note:** The SEEK filter is deprecated and will be removed in a future release of PDAF.
+
+{{{
+PDAF     Available options for SEEK:
+PDAF     --- Sub-types (Parameter subtype) ---
+PDAF       0: Evolve unit modes with finite difference approx. of TLM
+PDAF       1: like 0 with modes scaled by eigenvalues, unit U
+PDAF       2: Fixed basis vectors; variable U matrix
+PDAF       3: Fixed covariance matrix (V and U kept constant)
+PDAF     --- Integer parameters (Array param_int) ---
+PDAF       param_int(1): Dimension of state vector (>0), required
+PDAF       param_int(2): Ensemble size (>0), required
+PDAF       param_int(3): Interval for re-diagonalization of P (>0); optional: default 1
+PDAF       param_int(4): 1 for incremental updating, 0 else; optional: default 0
+PDAF     --- Floating point parameters (Array param_real) ---
+PDAF       param_real(1): Forgetting factor (usually >0 and <=1), required
+PDAF       param_real(2): epsilon for finite-difference approx. of TLM, required
+PDAF     --- Further parameters ---
+PDAF       n_modeltasks: Number of parallel model integration tasks
+PDAF           >=1 for subtypes 0 and 1; not larger than total number of processors
+PDAF           =1 required for subtypes 2 and 3
+PDAF       screen: Control verbosity of PDAF
+PDAF           0: no outputs
+PDAF           1: basic output (default)
+PDAF           2: 1 plus timing output
+PDAF           3: 2 plus debug output
+PDAF     +++++++++ End of option overview for the SEEK filter ++++++++++
+}}}