2 Copyright (C) 2008-2015 EDF R&D
4 This file is part of SALOME ADAO module.
6 This library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 This library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with this library; if not, write to the Free Software
18 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 See http://www.salome-platform.org/ or email : webmaster.salome@opencascade.com
22 Author: Jean-Philippe Argaud, jean-philippe.argaud@edf.fr, EDF R&D
24 .. index:: single: Blue
25 .. _section_ref_algorithm_Blue:
27 Calculation algorithm "*Blue*"
28 ------------------------------
33 This algorithm realizes a BLUE (Best Linear Unbiased Estimator) type estimation
34 of the state of a system. More precisely, it is an Aitken estimator.
36 This algorithm is always the fastest of all the assimilation algorithms of ADAO.
37 It is theoretically reserved for observation operator cases which are linear,
38 even if it sometimes works in "slightly" non-linear cases. One can verify the
39 linearity of the observation operator with the help of the
40 :ref:`section_ref_algorithm_LinearityTest`.
42 In case of non-linearity, even slightly marked, it will be easily prefered the
43 :ref:`section_ref_algorithm_ExtendedBlue` or the
44 :ref:`section_ref_algorithm_3DVAR`.
46 Optional and required commands
47 ++++++++++++++++++++++++++++++
49 .. index:: single: AlgorithmParameters
50 .. index:: single: Background
51 .. index:: single: BackgroundError
52 .. index:: single: Observation
53 .. index:: single: ObservationError
54 .. index:: single: ObservationOperator
55 .. index:: single: StoreSupplementaryCalculations
56 .. index:: single: Quantiles
57 .. index:: single: SetSeed
58 .. index:: single: NumberOfSamplesForQuantiles
59 .. index:: single: SimulationForQuantiles
61 The general required commands, available in the editing user interface, are the
65 *Required command*. This indicates the background or initial vector used,
66 previously noted as :math:`\mathbf{x}^b`. Its value is defined as a
67 "*Vector*" or a *VectorSerie*" type object.
70 *Required command*. This indicates the background error covariance matrix,
71 previously noted as :math:`\mathbf{B}`. Its value is defined as a "*Matrix*"
72 type object, a "*ScalarSparseMatrix*" type object, or a
73 "*DiagonalSparseMatrix*" type object.
76 *Required command*. This indicates the observation vector used for data
77 assimilation or optimization, previously noted as :math:`\mathbf{y}^o`. It
78 is defined as a "*Vector*" or a *VectorSerie* type object.
81 *Required command*. This indicates the observation error covariance matrix,
82 previously noted as :math:`\mathbf{R}`. It is defined as a "*Matrix*" type
83 object, a "*ScalarSparseMatrix*" type object, or a "*DiagonalSparseMatrix*"
87 *Required command*. This indicates the observation operator, previously
88 noted :math:`H`, which transforms the input parameters :math:`\mathbf{x}` to
89 results :math:`\mathbf{y}` to be compared to observations
90 :math:`\mathbf{y}^o`. Its value is defined as a "*Function*" type object or
91 a "*Matrix*" type one. In the case of "*Function*" type, different
92 functional forms can be used, as described in the section
93 :ref:`section_ref_operator_requirements`. If there is some control :math:`U`
94 included in the observation, the operator has to be applied to a pair
97 The general optional commands, available in the editing user interface, are
98 indicated in :ref:`section_ref_assimilation_keywords`. Moreover, the parameters
99 of the command "*AlgorithmParameters*" allows to choose the specific options,
100 described hereafter, of the algorithm. See
101 :ref:`section_ref_options_Algorithm_Parameters` for the good use of this
104 The options of the algorithm are the following:
106 StoreSupplementaryCalculations
107 This list indicates the names of the supplementary variables that can be
108 available at the end of the algorithm. It involves potentially costly
109 calculations or memory consumptions. The default is a void list, none of
110 these variables being calculated and stored by default. The possible names
111 are in the following list: ["APosterioriCovariance", "BMA", "CostFunctionJ",
112 "OMA", "OMB", "Innovation", "SigmaBck2", "SigmaObs2",
113 "MahalanobisConsistency", "SimulatedObservationAtBackground",
114 "SimulatedObservationAtOptimum", "SimulationQuantiles"].
116 Example : ``{"StoreSupplementaryCalculations":["BMA","Innovation"]}``
119 This list indicates the values of quantile, between 0 and 1, to be estimated
120 by simulation around the optimal state. The sampling uses a multivariate
121 gaussian random sampling, directed by the *a posteriori* covariance matrix.
122 This option is useful only if the supplementary calculation
123 "SimulationQuantiles" has been chosen. The default is a void list.
125 Example : ``{"Quantiles":[0.1,0.9]}``
128 This key allow to give an integer in order to fix the seed of the random
129 generator used to generate the ensemble. A convenient value is for example
130 1000. By default, the seed is left uninitialized, and so use the default
131 initialization from the computer.
133 Example : ``{"SetSeed":1000}``
135 NumberOfSamplesForQuantiles
136 This key indicates the number of simulation to be done in order to estimate
137 the quantiles. This option is useful only if the supplementary calculation
138 "SimulationQuantiles" has been chosen. The default is 100, which is often
139 sufficient for correct estimation of common quantiles at 5%, 10%, 90% or
142 Example : ``{"NumberOfSamplesForQuantiles":100}``
144 SimulationForQuantiles
145 This key indicates the type of simulation, linear (with the tangent
146 observation operator applied to perturbation increments around the optimal
147 state) or non-linear (with standard observation operator applied to
148 perturbated states), one want to do for each perturbation. It changes mainly
149 the time of each elementary calculation, usually longer in non-linear than
150 in linear. This option is useful only if the supplementary calculation
151 "SimulationQuantiles" has been chosen. The default value is "Linear", and
152 the possible choices are "Linear" and "NonLinear".
154 Example : ``{"SimulationForQuantiles":"Linear"}``
156 Information and variables available at the end of the algorithm
157 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
159 At the output, after executing the algorithm, there are variables and
160 information originating from the calculation. The description of
161 :ref:`section_ref_output_variables` show the way to obtain them by the method
162 named ``get`` of the variable "*ADD*" of the post-processing. The input
163 variables, available to the user at the output in order to facilitate the
164 writing of post-processing procedures, are described in the
165 :ref:`subsection_r_o_v_Inventaire`.
167 The unconditional outputs of the algorithm are the following:
170 *List of vectors*. Each element is an optimal state :math:`\mathbf{x}*` in
171 optimization or an analysis :math:`\mathbf{x}^a` in data assimilation.
173 Example : ``Xa = ADD.get("Analysis")[-1]``
175 The conditional outputs of the algorithm are the following:
177 APosterioriCovariance
178 *List of matrices*. Each element is an *a posteriori* error covariance
179 matrix :math:`\mathbf{A}*` of the optimal state.
181 Example : ``A = ADD.get("APosterioriCovariance")[-1]``
184 *List of vectors*. Each element is a vector of difference between the
185 background and the optimal state.
187 Example : ``bma = ADD.get("BMA")[-1]``
190 *List of values*. Each element is a value of the error function :math:`J`.
192 Example : ``J = ADD.get("CostFunctionJ")[:]``
195 *List of values*. Each element is a value of the error function :math:`J^b`,
196 that is of the background difference part.
198 Example : ``Jb = ADD.get("CostFunctionJb")[:]``
201 *List of values*. Each element is a value of the error function :math:`J^o`,
202 that is of the observation difference part.
204 Example : ``Jo = ADD.get("CostFunctionJo")[:]``
207 *List of vectors*. Each element is an innovation vector, which is in static
208 the difference between the optimal and the background, and in dynamic the
211 Example : ``d = ADD.get("Innovation")[-1]``
213 MahalanobisConsistency
214 *List of values*. Each element is a value of the Mahalanobis quality
217 Example : ``m = ADD.get("MahalanobisConsistency")[-1]``
220 *List of vectors*. Each element is a vector of difference between the
221 observation and the optimal state in the observation space.
223 Example : ``oma = ADD.get("OMA")[-1]``
226 *List of vectors*. Each element is a vector of difference between the
227 observation and the background state in the observation space.
229 Example : ``omb = ADD.get("OMB")[-1]``
232 *List of values*. Each element is a value of the quality indicator
233 :math:`(\sigma^b)^2` of the background part.
235 Example : ``sb2 = ADD.get("SigmaBck")[-1]``
238 *List of values*. Each element is a value of the quality indicator
239 :math:`(\sigma^o)^2` of the observation part.
241 Example : ``so2 = ADD.get("SigmaObs")[-1]``
243 SimulatedObservationAtBackground
244 *List of vectors*. Each element is a vector of observation simulated from
245 the background :math:`\mathbf{x}^b`.
247 Example : ``hxb = ADD.get("SimulatedObservationAtBackground")[-1]``
249 SimulatedObservationAtOptimum
250 *List of vectors*. Each element is a vector of observation simulated from
251 the analysis or optimal state :math:`\mathbf{x}^a`.
253 Example : ``hxa = ADD.get("SimulatedObservationAtOptimum")[-1]``
256 *List of vectors*. Each element is a vector corresponding to the observed
257 state which realize the required quantile, in the same order than the
258 quantiles required by the user.
260 Example : ``sQuantiles = ADD.get("SimulationQuantiles")[:]``
265 References to other sections:
266 - :ref:`section_ref_algorithm_ExtendedBlue`
267 - :ref:`section_ref_algorithm_3DVAR`
268 - :ref:`section_ref_algorithm_LinearityTest`
270 Bibliographical references: