[petsc-users] Non-linear solve: DIVERGED_LINE_SEARCH

[Karthikeyan Chockalingam - STFC UKRI]

Hello,

The non-linear solution diverged. The final solution seems right and I believe the Jacobian is correct (not 100% certain).

I am not sure if I doing something wrong in the solver setting.



 0 SNES Function norm 3.890991210938e-03

    0 KSP Residual norm 9.037762538598e+00

    1 KSP Residual norm 2.120375403775e-01

    2 KSP Residual norm 5.155439334511e-03

    3 KSP Residual norm 1.394364169369e-04

    4 KSP Residual norm 9.233543407204e-06

  Linear solve converged due to CONVERGED_RTOL iterations 4



      Line search: Using full step: fnorm 3.890991210938e-03 gnorm 7.701511565083e-06

  1 SNES Function norm 7.701511565083e-06

    0 KSP Residual norm 5.630229687829e-03

    1 KSP Residual norm 1.030475601271e-04

    2 KSP Residual norm 2.576454714319e-06

    3 KSP Residual norm 6.669316846898e-08

    4 KSP Residual norm 3.215810984829e-09

  Linear solve converged due to CONVERGED_RTOL iterations 4



      Line search: gnorm after quadratic fit 1.805500533481e-05

      Line search: Cubic step no good, shrinking lambda, current gnorm 2.563759884284e-05 lambda=3.0804668685096816e-02

      Line search: Cubic step no good, shrinking lambda, current gnorm 3.332721829751e-05 lambda=3.0804668685096817e-03

      Line search: Cubic step no good, shrinking lambda, current gnorm 4.102754045833e-05 lambda=3.0804668685096822e-04

      Line search: Cubic step no good, shrinking lambda, current gnorm 4.872893294880e-05 lambda=3.0804668685096822e-05

      Line search: Cubic step no good, shrinking lambda, current gnorm 5.643043250787e-05 lambda=3.0804668685096822e-06

      Line search: Cubic step no good, shrinking lambda, current gnorm 6.413194279696e-05 lambda=3.0804668685096827e-07

      Line search: Cubic step no good, shrinking lambda, current gnorm 7.183345417492e-05 lambda=3.0804668685096828e-08

      Line search: Cubic step no good, shrinking lambda, current gnorm 7.953496567312e-05 lambda=3.0804668685096829e-09

      Line search: Cubic step no good, shrinking lambda, current gnorm 8.723647719173e-05 lambda=3.0804668685096831e-10

      Line search: Cubic step no good, shrinking lambda, current gnorm 9.493798871875e-05 lambda=3.0804668685096832e-11

      Line search: Cubic step no good, shrinking lambda, current gnorm 1.026395002516e-04 lambda=3.0804668685096835e-12

      Line search: Cubic step no good, shrinking lambda, current gnorm 1.103410117889e-04 lambda=3.0804668685096835e-13

      Line search: unable to find good step length! After 12 tries

      Line search: fnorm=7.7015115650831560e-06, gnorm=1.1034101178892401e-04, ynorm=6.2052357872955976e-03, minlambda=9.9999999999999998e-13, lambda=3.0804668685096835e-13, initial slope=-5.9313318983096354e-11

Nonlinear solve did not converge due to DIVERGED_LINE_SEARCH iterations 1


Thank you for your help.

Kind regards,
Karthik.

--
Dr. Karthik Chockalingam
Senior Research Software Engineer
High Performance Systems Engineering Group
Hartree Centre | Science and Technology Facilities Council
karthikeyan.chockalingam at stfc.ac.uk<mailto:karthikeyan.chockalingam at stfc.ac.uk>

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