Handling contraints with dolfinx MPC

dolfinx
1

Hello,

I am trying to use MPC to implement constraints in dolfinx, and I wonder whether MPC can support that

  • the slave of one constraint also appears as a master for another constraint, or
  • the slave of one constraint also appears as the slave for another constraint;

in other words, once a DOF is used as a slave for one constraint, can it appear at all in another constraint?

Many thanks in advance!

2

MPC does not support:

This is because this would cause an infinite recursion, and cannot be efficiently implemented.

That would be something like
u_1= u_5+ 2*u_10,
u_1=u_3-u_4
Which can be reduced to
u_3 = u_5 + 2 u_10 + u_4.

Thus you should set up this constraint, instead of trying to do this implicitly.

This also comes back to the fact that checking every constraint for other potential constraints that would modify an already set constraint is very inefficient.