[petsc-users] SNES solver

[Tian(ICT)]

What does this output really mean?
Why does a converged Newton iteration still lead to a diverged SNES solve?

C:\cygwin\home\rabbit\pGFEM-test>pgfem -ksp_monitor
atol=1e-050, rtol=1e-008, stol=1e-008, maxit=50, maxf=10000
  0 KSP Residual norm 1.526322665926e-001
  1 KSP Residual norm 1.664108108313e-003
  2 KSP Residual norm 9.234526593231e-006
  3 KSP Residual norm 7.035003988413e-008
  0 KSP Residual norm 1.372225675693e-001
  1 KSP Residual norm 1.955889208728e-003
  2 KSP Residual norm 6.925412512315e-006
  3 KSP Residual norm 1.652845110783e-008
  0 KSP Residual norm 1.233183603661e-001
  1 KSP Residual norm 1.751093239951e-003
  2 KSP Residual norm 6.124066396591e-006
  3 KSP Residual norm 1.431288831469e-008

C:\cygwin\home\rabbit\pGFEM-test>pgfem -ksp_monitor -snes_monitor
atol=1e-050, rtol=1e-008, stol=1e-008, maxit=50, maxf=10000
  0 SNES Function norm 1.000000000000e+002
  0 KSP Residual norm 1.526322665926e-001
  1 KSP Residual norm 1.664108108313e-003
  2 KSP Residual norm 9.234526593231e-006
  3 KSP Residual norm 7.035003988413e-008
  1 SNES Function norm 9.112654908737e+001
  0 KSP Residual norm 1.372225675693e-001
  1 KSP Residual norm 1.955889208728e-003
  2 KSP Residual norm 6.925412512315e-006
  3 KSP Residual norm 1.652845110783e-008
  2 SNES Function norm 8.914492398201e+001
  0 KSP Residual norm 1.233183603661e-001
  1 KSP Residual norm 1.751093239951e-003
  2 KSP Residual norm 6.124066396591e-006
  3 KSP Residual norm 1.431288831469e-008
  3 SNES Function norm 8.937681381791e+001
STEP 0 (Newton iterations: 3)

diverged reason: -6

--Rong