[petsc-users] What could be the reason for a convergence history like this one?

Tue Feb 9 12:25:39 CST 2010

Did you try checking your Jacobian using -snes_mf?

   Matt

On Tue, Feb 9, 2010 at 12:21 PM, (Rebecca) Xuefei YUAN
<xy2102 at columbia.edu>wrote:

> Hi,
>
> The SNES convergence history shows the residual increases or stop
> decreasing starting at some iteration. I ran two different cases for the
> same code, and the history looks similar, what could be wrong with the code?
>
> Thanks very much!
>
> Case 1:
>  0 SNES Function norm 9.593111354483e-01
>  1 SNES Function norm 1.233321371555e-01
>  2 SNES Function norm 2.926382110614e-02
>  3 SNES Function norm 2.091318748212e-02
>  4 SNES Function norm 1.047907743570e-02
>  5 SNES Function norm 4.462043675959e-03
>  6 SNES Function norm 1.851050848655e-03
>  7 SNES Function norm 4.417550480988e-04
>  8 SNES Function norm 1.736388356513e-04
>  9 SNES Function norm 6.300414578098e-05
>  10 SNES Function norm 1.929829710585e-05
>  11 SNES Function norm 1.506367625001e-05
>  12 SNES Function norm 1.480567720594e-05
>  13 SNES Function norm 1.470754287980e-05
>  14 SNES Function norm 1.461728595512e-05
>  15 SNES Function norm 1.453616609384e-05
>  16 SNES Function norm 1.441040320141e-05
>  17 SNES Function norm 1.402352953635e-05
>  18 SNES Function norm 1.343005745899e-05
>  19 SNES Function norm 1.328043697395e-05
>  20 SNES Function norm 1.327501784736e-05
>  21 SNES Function norm 1.327431008405e-05
>  22 SNES Function norm 1.327343169426e-05
>  23 SNES Function norm 1.327273768560e-05
>  24 SNES Function norm 1.327185496127e-05
>  25 SNES Function norm 1.327119625499e-05
>  26 SNES Function norm 1.327071509157e-05
>  27 SNES Function norm 1.327038695378e-05
>  28 SNES Function norm 1.326990549326e-05
>  29 SNES Function norm 1.326917602672e-05
>  30 SNES Function norm 1.326830723835e-05
>  31 SNES Function norm 1.326796002362e-05
>  32 SNES Function norm 1.326777827731e-05
>  33 SNES Function norm 1.326755622116e-05
>  34 SNES Function norm 1.326732752144e-05
>  35 SNES Function norm 1.326698050145e-05
>  36 SNES Function norm 1.326640877572e-05
>  37 SNES Function norm 1.326587074902e-05
>  38 SNES Function norm 1.326573931166e-05
>  39 SNES Function norm 1.326564241601e-05
>  40 SNES Function norm 1.326548432075e-05
>  41 SNES Function norm 1.326531590041e-05
>  42 SNES Function norm 1.326531590043e-05
>  43 SNES Function norm 1.326531590045e-05
>  44 SNES Function norm 1.326531590044e-05
>  45 SNES Function norm 1.326531590044e-05
>  46 SNES Function norm 1.326531590043e-05
>  47 SNES Function norm 1.326531590045e-05
>  48 SNES Function norm 1.326531590044e-05
>  49 SNES Function norm 1.326531590046e-05
>  50 SNES Function norm 1.326531590046e-05
> Nonlinear solve did not converge due to DIVERGED_MAX_IT
>
> case 2:
>  0 SNES Function norm 1.489006328086e+00
>  1 SNES Function norm 1.044141602147e-01
>  2 SNES Function norm 2.662563646189e-02
>  3 SNES Function norm 5.764005178654e-03
>  4 SNES Function norm 2.493444656346e-03
>  5 SNES Function norm 5.180475798178e-04
>  6 SNES Function norm 4.166251801170e-04
>  7 SNES Function norm 3.066582000814e-04
>  8 SNES Function norm 2.189666367666e-04
>  9 SNES Function norm 1.354684191244e-04
>  10 SNES Function norm 1.287520392923e-04
>  11 SNES Function norm 1.286080621054e-04
>  12 SNES Function norm 1.285437650356e-04
>  13 SNES Function norm 1.284168806812e-04
>  14 SNES Function norm 1.283833115348e-04
>  15 SNES Function norm 1.283700090330e-04
>  16 SNES Function norm 1.283691578788e-04
>  17 SNES Function norm 1.283486627334e-04
>  18 SNES Function norm 1.283349991927e-04
>  19 SNES Function norm 1.283332060308e-04
>  20 SNES Function norm 1.283026682165e-04
>  21 SNES Function norm 1.282981662835e-04
>  22 SNES Function norm 1.282944044720e-04
>  23 SNES Function norm 1.282831861627e-04
>  24 SNES Function norm 1.282754274487e-04
>  25 SNES Function norm 1.282754274487e-04
>  26 SNES Function norm 1.282754274487e-04
>  27 SNES Function norm 1.282754274487e-04
>  28 SNES Function norm 1.282754274487e-04
>  29 SNES Function norm 1.282754274487e-04
>  30 SNES Function norm 1.282754274487e-04
>  31 SNES Function norm 1.282754274487e-04
>  32 SNES Function norm 1.282754274487e-04
>  33 SNES Function norm 1.282754274487e-04
>  34 SNES Function norm 1.282754274487e-04
>  35 SNES Function norm 1.282754274487e-04
>  36 SNES Function norm 1.282754274487e-04
>  37 SNES Function norm 1.282754274487e-04
>  38 SNES Function norm 1.282754274487e-04
>  39 SNES Function norm 1.282754274487e-04
>  40 SNES Function norm 1.282754274487e-04
>  41 SNES Function norm 1.282754274487e-04
>  42 SNES Function norm 1.282754274487e-04
>  43 SNES Function norm 1.282754274487e-04
>  44 SNES Function norm 1.282754274487e-04
>  45 SNES Function norm 1.282754274487e-04
>  46 SNES Function norm 1.282754274487e-04
>  47 SNES Function norm 1.282754274487e-04
>  48 SNES Function norm 1.282754274487e-04
>  49 SNES Function norm 1.282754274487e-04
>  50 SNES Function norm 1.282754274487e-04
>
> Thanks a lot!
>
> --
> (Rebecca) Xuefei YUAN
> Department of Applied Physics and Applied Mathematics
> Columbia University
> Tel:917-399-8032
> www.columbia.edu/~xy2102 <http://www.columbia.edu/%7Exy2102>
>
>

-- 
What most experimenters take for granted before they begin their experiments
is infinitely more interesting than any results to which their experiments
lead.
-- Norbert Wiener
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