Published on *OpenMx* (http://openmx.psyc.virginia.edu)

By *kspoon*

Created *04/18/2012 - 19:30*

Wed, 04/18/2012 - 19:30 — kspoon [1]

I know there's another similar active thread, but I didn't want to highjack it. Most of the threads I've seen in regards to this error message have some reference to an iteration or line - mine does not. What's in the subject is the entire error.

I'm attempting to model a 'saturated' model for pathway analysis - working with a twin data set. A true saturated model shows all our path diagrams to be a much more horrible fit to the data (p-values < 10^-10), but I believe I'm getting penalized since we have constraints that the pathways are the same for all 4 groups - within (A and B) and across (MZ and DZ). So, my goal was to make a 'saturated' model instead, constraining the necessary parts within the covariance matrix and across the covariance matrices the same.

I've spent a lot of time playing with starting values - choosing some data driven values (which required some massaging to be positive definite to start) and some rather dumb values (off diagonal elements to .5 and diagonal elements to 1).

Is this truly just a starting value problem? Or are my constraints causing the issue? Any advice would be appreciated. I've attached faked correlation matrices for both groups and my code - which I admit is probably horrible to look at and try to parse through. I feel like my error is likely conceptual and completely based on some horrible misunderstanding on my part.

Thanks!

Attachment | Size |
---|---|

ExpCovPOSDEF.R [2] | 6.6 KB |

DZcor.csv [3] | 2.56 KB |

MZcor.csv [4] | 2.58 KB |

**Links:**

[1] http://openmx.psyc.virginia.edu/users/kspoon

[2] http://openmx.psyc.virginia.edu/sites/default/files/ExpCovPOSDEF.R

[3] http://openmx.psyc.virginia.edu/sites/default/files/DZcor.csv

[4] http://openmx.psyc.virginia.edu/sites/default/files/MZcor.csv

[5] http://openmx.psyc.virginia.edu/thread/1366

[6] http://openmx.psyc.virginia.edu/thread/1364

[7] http://openmx.psyc.virginia.edu/forums/openmx-help/openmx-error-messages