15.5. List of commands and keywords for a dedicated task or study oriented case¶

We summarize here all the commands and keywords available to describe a dedicated task or study oriented case by avoiding the particularities of each algorithm. It is therefore a common inventory of commands.

All the possible terms, nested or not, are listed by alphabetical order. They are not required for all the algorithms. The commands or keywords available are the following

AlgorithmParameters: Dictionary. This variable indicates the data assimilation or optimization algorithm chosen by the keyword “Algorithm”, and its potential optional parameters. The potential choices by this keyword “Algorithm” are available through the graphical interface or in the reference documentation containing a specific sub-section for each of them. There are for example the “3DVAR”, the “Blue”, etc. Optionally, the command also allows to add parameters to control the chosen algorithm. Their values are defined either explicitly or in a “Dict” type object. See the Description of options of an algorithm by “AlgorithmParameters” for the detailed use of this command part.

Background: Vector. The variable indicates the background or initial vector used, previously noted as $\mathbf{x}^b$ . Its value is defined as a “Vector” or “VectorSerie” type object. Its availability in output is conditioned by the boolean “Stored” associated with input.

Debug

Boolean value. This variable define the level of trace and intermediary debug information. The choices are limited between 0 (for False) and 1 (for True).

Example : {"Debug":False}

Observation: List of vectors. The variable indicates the observation vector used for data assimilation or optimization, and usually noted $\mathbf{y}^o$ . Its value is defined as an object of type “Vector” if it is a single observation (temporal or not) or “VectorSeries” if it is a succession of observations. Its availability in output is conditioned by the boolean “Stored” associated in input.

ObservationOperator: Operator. The variable indicates the observation operator, usually noted as $H$ , which transforms the input parameters $\mathbf{x}$ to results $\mathbf{y}$ to be compared to observations $\mathbf{y}^o$ . Its value is defined as a “Function” type object or a “Matrix” type one. In the case of “Function” type, different functional forms can be used, as described in the section Requirements for functions describing an operator. If there is some control $U$ included in the observation, the operator has to be applied to a pair $(X,U)$ .

Observers: List of functions linked to variables. This command allows to set internal observers, that are functions linked with a particular variable, which will be executed each time this variable is modified. It is a convenient way to monitor variables of interest during the data assimilation or optimization process, by printing or plotting it, etc. Common templates are provided to help the user to start or to quickly make his case.

StudyName: String. This variable is an open string to identify or describe the ADAO study by a name or a sentence.

StudyRepertory: String. If available, the directory specified by this string is used as base name for calculation, and also used to find all the script files given by name without path, that can define some other commands by scripts.