Dear all
I have two ConstraintMatrix objects A and B. I wish to remove from A dof
constrained in A that are already constrained in B.
My strategy is as follows:
loop over all dof dd
check if the dof dd is constrained in A:
A.is_constrained(dd)
check if the dof dd is constrained in B:
B.is_constrained(dd)
if the current dof dd is constrained in A but not in B then I
add the current dof to an IndexSet called filter
end_loop
Now I wish to use the method add_selected_constraints to create a reduced
version of the ConstraintMatrix A that excludes the dof constrained in A that
are also constrained in B. Naively, I thought the following would work:
ConstraintMatrix C(A);
A.clear ();
A.add_selected_constraints(C, filter);
The problem is that filter is not a list of dof. Rather, based on the
documentation and source, it appears to be the line number or some internal
storage index. The documentation states:
"Constrained dofs are transformed to local index space of the filter"
How does one create a filter then as there appears to be no way to obtain the
line index from the dof?
Here is an example where I assumed (wrongly) the filter was a list of dof:
The ConstraintMatrix A I wish to copy from is:
0 = 0
1 = 0
2 = 0
3 = 0
5 = 0
6 = 0
7 = 0
The IndexSet named filter is:
{[0,3], [5,7]}
Note, 4 is unconstrained in A and is not in the filter either
So if I call the method add_selected_constraints from an empty ConstraintMatrix
C I would expect to get the ConstraintMatrix A again.
ConstraintMatrix C;
C.add_selected_constraints(A,filter);
But I get this for C:
0 = 0
1 = 0
2 = 0
3 = 0
4 = 0
5 = 0
6 = 0
7 = 0
So, now 4 appears constrained in C! This must be wrong as 4 is not in the
filter and the documentations states:
"elements not present in the IndexSet are ignored"
What am I missing?
Any help is, as usual most appreciated.
Kind regards
Andrew
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