I'm using SNES for a finite element contact solve, in which the sparsity pattern of the jacobian can change from one Newton iteration to the next (since the nodes on the contact surface move).
In order to handle this I figured the best way would be to destroy the jacobian matrix and re-allocate it with a new sparsity pattern inside each call to FormJacobian, does that seem like a reasonable approach in this context? Also, I recall from an earlier discussion that this matrix re-allocation inside FormJacobian is supported by SNES, but I just wanted to confirm that? Also, I was wondering if there is any example where the matrix is re-allocated inside SNES iterations so that I can make sure that I do it correctly? Best regards, David