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Treatment of code 6

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wuhao_osu's picture
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Joined: 09/07/2010 - 17:14
Treatment of code 6

Hello,

I got several code 6 when running simulations. Some of those cases have a near singular estimated hessian, though the calculated hessian is fine. Is this the source of non-convergence? Would it work to re- run the data with the parameter estimates as initial values? Is it possible to have the optimizer use the calculated hessian all the time?

Thanks

- Hao

neale's picture
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Joined: 07/31/2009 - 15:14
Yes, code 6 is more likely to

Yes, code 6 is more likely to occur if the estimated Hessian is inaccurate, especially if it is nearly singular.

Indeed it is a good idea to rerun such models from their solutions, which is extremely easy to do in OpenMx.

fittedModel refittedModel

This procedure may be repeated if refittedModel fits better than originalModel. If it doesn't then a third run is unlikely to help.

Also, it is a good idea to try other starting values in the originalModel

tbates's picture
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Joined: 07/31/2009 - 14:25
sounds like good information

sounds like good information (in the "what to do now" section ) to add to the code 6 error message

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