DRAFT: Remove runtime type selection

[mattmartineau]

Managing runtime selection of the supported types in AmgX makes the code more complex but doesn't seem to benefit users significantly from our discussions so far.

This is a draft pull request that will eventually remove all runtime type selection and instead allow users to choose type at compile time.

[mattmartineau]

Yes that's exactly correct - the current version is just hacked but it shows the desired outcome of having only compile time type selection. CMake flags like you suggested will be necessary.

Thanks

[marsaev]

Do you think having C++ interface would make sense?

[mattmartineau]

If you mean generally for AmgX then, yes, I definitely do - we have been considering it for a while.