1620 Compare Module and Data Source keyword

[rhinoella]

Module to compare two datasets and a new keyword to manage data sources

Compare Module

• Module to replace the old 'DataTest' module with added functionalities
• Currently this PR does not include the GUI implementation, as I think it is better in a different PR

Data Source Keyword

• A keyword that creates Data objects (Data1D, Data2D, Data3D, etc.) from user-specified internal or external data
• Can accept up to two different data sources depending on the needs of the module

Notes

• Compare module is currently only able to handle Data1D sources

Closes #1620

[trisyoungs]

I may not be fully awake while going through this, but it feels kinda overkill for what we want to do, and I fear is dragging us away from just getting a working 1D comparison up and running correctly, with multiple datasets, which is what we really need.

Perhaps I'm mistaking your intent, but at present this feels like its written to be a catch-all class that can store multiple different dimensionalities of data (which we don't want) rather than something more akin to a templated class taking, for instance, the type and file format (Data1D and Data1DImportFileFormat) and which then has specialisations to handle the difficult parts that don't translate across dimensionalities (e.g. the fact that Data1D derives from a base class, and which complicates the search for internal data of that type).

[rhinoella]

I may not be fully awake while going through this, but it feels kinda overkill for what we want to do, and I fear is dragging us away from just getting a working 1D comparison up and running correctly, with multiple datasets, which is what we really need.

Perhaps I'm mistaking your intent, but at present this feels like its written to be a catch-all class that can store multiple different dimensionalities of data (which we don't want) rather than something more akin to a templated class taking, for instance, the type and file format (Data1D and Data1DImportFileFormat) and which then has specialisations to handle the difficult parts that don't translate across dimensionalities (e.g. the fact that Data1D derives from a base class, and which complicates the search for internal data of that type).

@trisyoungs The intent is to have a DataSource template class that can handle Data1D, 2D and 3D objects depending on what the type is specified as:

https://github.com/disorderedmaterials/dissolve/blob/713c3528a866636c2e900480d2dae601d2843f72/src/modules/compare/compare.cpp#L10C5-L18C5

The specialisation (Data1D requiring a different search function) has to be handled in Compare.cpp, as it requires the ModuleContext object which is provided in the Compare::process() function. So the main function of DataSource is to accept a set of internal/external data (1D, 2D or 3D depending on what is specified), construct a vector of the relevant object (Data1D, Data2D or Data3D) and add it to the module's data through the module's addData() function that is passed into its constructor.

[trisyoungs]

@rhinoella Because of the need to have the processing module data to search? Couldn't you just pass this in as a const reference when creating the keyword?

[rhinoella]

@trisyoungs Unfortunately the moduleContext object is only known and constructed during runtime, when it is passed into the Compare::process() function during Dissolve::iterate(), so the keyword is constructed before the moduleContext object is created.

[trisyoungs]

@rhinoella True true. Alas, module constructors used to get passed the main Dissolve& object, but no longer, and so you could have gotten the GenericList from there. Curses to this design! I guess you'd better just work this up, focussing on the 1D case, and see where you get to.

[rhinoella]

Changes

• Type definition for a Data classes' associated file and format is stored in the class. This improves type-safety (prevents someone from using a Data2D object with a Data1DImportFileFormat) and also means that the template class DataSourceKeyword only needs one template parameter- the data class
• DataSource class stores the Data object and Format object as an std::variant instead of a std::unique_ptr as this further improves type safety

Note

Due to the removal of unique_ptr, the DataBase class (parent class for Data1DBase, Data2DBase and Data3DBase) can also be removed. I left it in anyways because it reduces code-repetition but please let me know if it should be removed.

[rprospero]

Everything looks really good. I've just included one small change to fix the Windows build.

[trisyoungs]

Looking really very nice indeed. I have a bunch of formatting comments, but nothing more than that.

Applied changes