Add notes on porting rbf mapping configurations

[davidscn]

... as required by precice/precice#1550

[MakisH]

I have not followed the discussion on this feature, but are we now going back from the simple <mapping:rbf ... > with automatic algorithm selection to <mapping::rbf-global-direct ...> and <<mapping:rbf-global-iterative ...>?

Have you already considered keeping the <mapping:rbf ...> with a default option?

Remember that we used to have rbf and petrbf, which was always difficult to explain.

[davidscn]

I have not followed the discussion on this feature, but are we now going back from the simple <mapping:rbf ... > with automatic algorithm selection to <mapping::rbf-global-direct ...> and <<mapping:rbf-global-iterative ...>?

No. Did you read careful enough or do I need to be more explicit?

[MakisH]

I have not followed the discussion on this feature, but are we now going back from the simple <mapping:rbf ... > with automatic algorithm selection to <mapping::rbf-global-direct ...> and <<mapping:rbf-global-iterative ...>?

No. Did you read careful enough or do I need to be more explicit?

It's complicated. I think I read it in the same speed as a user would read it, but I got confused. Part of the reason was that I had the (wrong) impression that we already had <mapping:rbf> as a tag, or that we at least discussed it at some point (it would be great to have it to auto-generate default configs).

Reading it again, the subtags are great, but this documentation entry could largely benefit from a diff code block with a concrete example. Right now, there is simply too much to follow in inline text.