(relauncher_tmaster_dealing_attributes)=
# Dealing with attributes

Disregarding the kind of master considered (the `TLauncher2`, discussed briefly below or those 
introduced in the optimisation part, in [](#reoptimizer_problem) for instance), there are common 
methods that are discussed below in order to simplify or precise some important behaviour of your 
current analysis.

In simple problem, the `TDataServer` object and the ones deriving from `TEval` have input parameters 
that fit together. In this case, you can use the `addAllInputs` method from the `TEval` class to 
define the `TDataServer` needed header (the only argument being a pointer to the considered 
dataserver object). For more complex one, there might be a mismatch.

In other problem, one can distinguish between three kinds of situation:

- The `TEval`-based object is using few input parameters, one (or more) of which is requested to be 
set a constant value for all the upcoming estimation. To do this properly, the parameter under 
consideration should be added to the assessor but not to the dataserver. The method 
`addConstantValue` from the chosen `TMaster` inheriting object is called with argument the pointer 
to the attribute and its value as second parameter. A third optionnal parameter (set by default at 
false) specifies whether this value should be stored in the dataserver tuple at the end. This option 
has been recently added as it might be better for bookkeeping to know what the underlying hypothesis 
was when the computations were performed. An example of how to use this is provided in 
[](#use_cases_macro_relauncher). This method has also been implemented to be able to cope with 
vectors and strings but this implies to handle complicated concept that are used internally, so we 
strongly recommand to contact us if you have no other choice.

- The `TEval`-based object (or more oftently the composition of evaluators) is using many internal 
parameters (attribute that are created from one assessor and used by any other later on in the chain). 
If these parameters are uninteresting for the final purpose of the analysis, they can be removed, 
simply by calling the `addTemporary` method from the chosen `TMaster` inheriting object. The only 
argument is a pointer to the attribute under consideration. Once more, an example of how to use this 
is provided in [](#use_cases_macro_relauncher).

- Finally, in some pure launching problem (Sobol for instance), some {{tds}}-objects have extra 
parameters unused by the `TEval`. In this case, it means that the initial {{tds}} is not empty and 
that the `TMaster`-object is able to keep this parameters values, and completes the data by adding 
columns.