Hi, If I may, is this what you want ?
https://petsc.org/main/docs/manualpages/SNES/SNESSetLagJacobian.html Pierre On 03/05/2022 06:21, Tang, Qi wrote:
Hi, Our code uses FDcoloring to compute Jacobian. The log file indicates most of time is spent in evaluating residual (2600 times in one Newton solve) while it only needs 3 nonlinear iterations and 6 total linear iterations thanks to the fieldsplit pc. As a temporary solution, is it possible to evaluate Jacobian only once in one Newton solve? This should work well based on my other experience if pc is very efficient. But I cannot find such a flag. Is there any other solution, other than implementing the analytical Jacobian? Thanks, Qi
