[petsc-users] Modifying Jacobian and Preconditioner in a Loop

[Kevin Mattalo]

Hello,

I am currently solving a large linear system using a discontinuous Galerkin
approach with an inexact Newton method. I begin with a small time step and
then ramp up the time step every m outer iterations. I lag the update of
both by a certain integer multiple to improve efficiency. Because of this,
my Jacobian and therefore the preconditioner need to be modified,
reassembled, and updated in a loop. Right now, for each update I zero the
entries in my Jacobian, compute the entries, assemble the matrix, reset my
operators using KSPSetOperators() and then call KSPGetPC and KSPSetUp() to
get the new preconditioner.

Is there a more efficient way to continuously update the Jacobian?

Kevin
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