In GitLab by @valentjn on May 19, 2016, 12:57

Currently, you need OperationMultipleHierarchisation from optimization to hierarchize with B-splines. This should somehow be merged into base's OperationHierarchisation; or, at least, OperationHierarchisation should give useful hints that the optimization module has to be used.

Closely related with this issue is the solving of linear systems within the optimization module. This should likely be in the solver module, but base with the B-splines hierarchization shouldn't depend on other modules. We have to think about this...