[petsc-users] Quasi newton

Tang, Qi tangqi at msu.edu
Mon May 2 23:21:12 CDT 2022

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?


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