======================================================
With the new solver ability to identify groups of dependent parameters, even with SparseQR, it is now possible to properly implement Blocked constraint (blocked geometry state/mode).
This comes at the cost of two consecutive diagnosis (4 QR decompositions, running in parallel by pairs, so the double of time than when not using any blocked constraint).
A first diagnosis identifies the groups of dependent solver parameters.
If any of these groups comprises a parameter affected by a blocked constraint, the parameter is fixed. As only one parameter from each group is fixed, there are no (partly) redundant parameters involved.
Then the new adapted system is solved.
07725ede25