ADR Suggestion Calculator Factory

[andped10]

In version 1.1.2 of the EasyScience we rely on the class Objects.Inferface.InterfaceFactoryTemplate to obtain functionality to determine the result/response from a sample. In reflectometry these results/responses are the reflectivity curve and the SLD curve. The current solution allows the user to change between different physics calculators by switching the state of the "Factory".

There are several issues with the current setup:

• The name Interface way to generic and even misleading. Instead it should be Calculator
• Another challenge with the generic naming approach is that the main method is called fit_func that is complete non-explanatory
• It is confusing that the code part is called a Factory since it doesn't produce any objects as expected from a factory pattern
  • Not sure, but create actually seems to produce an interface (calculator)
• Its state is complex to maintain (which physical calculator that is being used)
  • It has complicated dependencies (generate_bindings)
  • Might even have to update the Fitter

In an attempt to simplify the calculator functionality the following changes are suggested:

• Change towards a setup similar to fitting.minimizers where the factory is only responsible for producing the requested calculator object
  • No state information should be hold be the factory
• The produced calculator would correspond to one and only one physical model
• The constructor for the produced calculator should take a model/sample as its main argument
  • Only able to do single point calculations for this provided model/sample
  • Could have method to update the model/sample
• The produced calculator should probably have a method with a generic name that would be called when doing fitting
  • Can be ensured by having an base class for the calculators where this method is defined as abstract
• At the EasyScience level it will probably only be a matter of defining the calculator base class and defining an abstract base factory to ensure that such calculator objects are returned
• The concrete calculator factory would be implemented in the product specific EasyXXXLib repo similar to where the interfaces (calculators) are implemented