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nuclear twin family design in OpenMx

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qingwen's picture
Joined: 08/15/2019 - 09:48
nuclear twin family design in OpenMx
Binary Data NTF.R7.4 KB

Hi, all

I am trying to fix a Nuclear Twin Family model in OpenMx.

Genetic and environmental parameter estimates in my model are obtained from four pieces of information, the covariance between MZ twins, the covariance between DZ twins and the covariance between parents and the covariance between parents and children.

I want to use the code posted in there, but this code seems to have a bug(losing all objects). I don't know whether the estimated parameters are correct. If they are correct, how to deal with the bug? I found some essay using Mx to fix NTF model but not openMx. I want to know if openMx can fix NTF model.

Thank you in advance

mkeller's picture
Joined: 08/04/2009 - 16:02


This is Matt K - coauthor on that script. It's certainly possible to using OpenMx to run NTF designs (and it's actually a hell of a lot easier than in old Mx!). I'm not sure what you mean by "losing objects" and it's tough to debug the script without having your data. Can you send an example datafile, or at least the first couple of lines?

If it's any help, here's another script where, at the bottom, is a very simple NTFD.


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qingwen's picture
Joined: 08/15/2019 - 09:48
ADFE model

Dear Matt,

I am very glad to receive your reply.

I studied your file attachments carefully. I think the script you provided at the bottom might be seen as a ADSE model. Do I understand it correctly?

I wrote a script for ADFE model on the basis of the simple NTFD. In this model, I add the familial path(i.e., m), the covariance between A and F(i.e., w) and the variance of F(i.e., x1). I also fix s=0. And then, I made a AFE model and a AE model through setting certain path(s) to zero.

Here is my script and a small section of my data. The program could run but I am not sure whether the equations in the nonlinear constraints section are right.

In addition, I have got two questions for the results. They also happen when running all the data I have.

First, there is a warning message like that for some models. Is this kind of result acceptable?

Run the model

> ADFE.NTF.Fit <- mxRun(ADFE.NTF.Model,intervals=FALSE)
Running ntfADFE with 11 parameters
Warning message:
In model 'ntfADFE' Optimizer returned a non-zero status code 1. The final iterate satisfies the optimality conditions to the accuracy requested, but the sequence of iterates has not yet converged. Optimizer was terminated because no further improvement could be made in the merit function (Mx status GREEN).

Second, m is estimated to be negative in some models. Is it normal?

Thank you in advance. I am looking forward to your reply.


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