Reset the Dirichelet boundary condition

General Discussion
1

Dear all,

Is the an example about resetting the Dirichlet boundary condition after modifying a PETSc matrix?

For example,

Mat A;
A=a(Vh, Vh, tgv=-1);
rhs=a(0,Vh, tgv=-1);
a modification of A and rhs;

We then need to reset the locking conditions in A and rhs.

Best,
Yongxing.

2

No, you need to copy the matrix before you modify it if you need the conditions back in afterwards.