OpenMx General Help

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Picture of user. rabil Joined: 01/14/2010

Handling Exogenous Latent Variables in OpenMx

Suppose you have two exogenous latent variable. (There will be directed paths from them to a response variable.) Is the covariance between the two exogenous latent variables part of the model? That is, do I have to include a path specification for the covariance or otherwise the covariance will be constrained to zero? I understand that the covariances among exogenous manifest variables are not part of the model.
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Picture of user. rabil Joined: 01/14/2010

How can you tell if OpenMx is using multiple cores?

I'm running OpenMx on 4 different computers running Ubuntu 15.04 and the latest version of OpenMx and current versions of R. On one, when look at the output for htop, it seems clear that all 4 cores are being used by OpenMx. Yet on two of the others, htop seems to indicate that not all 4 cores are being used simultaneously and the same model takes 2 to 3 times longer to run.
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Picture of user. tbates Joined: 07/31/2009

access model estimated parameters (EP) without calling summary?

Hi OpenMxers,
I want to determine automatically which order to put models into mxCompare so that the model with more degrees of freedom comes first.

Both models have been run, and I can access a models number of estimated parameters from summary(model).

summary() however, can be costly in terms of execution time: Is there a way to access the EP (or df) property from the model directly without calling summary?

Besten Wünsche,
tim

FYI, the situation I am trying to automate is avoiding this:

|Model        | EP|Delta-2LL |Delta df|p  |      AIC|Compare with Model |
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No user picture. Rachel Joined: 02/08/2012

mxTryHard status codes

Dear all,

I have been running a model within a loop over several variables, which does not converge well for all variables. Therefore, I applied mxTryHard. There are two things I noticed:

1) for models that run well without calling mxTryHard the best fit does not seem to change using mxTryHard, but the status code changes from 0 to -1

> fit1 <- mxRun(model,intervals =F)
> fit1$output$Minus2LogLikelihood
[1] 4595.342
> fit1$output$status
$code
[1] 0
$status
[1] 0

fit2<-mxTryHard(model,intervals=F)
> fit2$output$Minus2LogLikelihood
[1] 4595.342
fit2$output$status
$code

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No user picture. Anonymous (not verified) Joined: 09/16/2024

Can't move paths

Hi, I'm using Onyx, which I think is based on OpenMx, for a confirmatory factor analysis.

I'm using a Macbook Air, and I can't work out how to modify the path arrows so they look neat. Can anyone help?

There is nothing in the documentation. The models in the examples all look nice, whereas everytime I add a path or covariance path, the program sticks them in anywhere and I can't move the end-points around to different parts of the observed or latent variable.

Please help!

Jay.

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Picture of user. rabil Joined: 01/14/2010

Modifying an Existing Model

I created a model (using a function) saved as "x". I would like to change a label in the A matrix. Here are the labels for the A matrix:

> x$matrices$A$labels
v_1 v_2 v_3 mu
v_1 NA NA NA "b_1"
v_2 NA NA NA "b_2"
v_3 NA NA NA "b_3"
mu NA NA NA NA

I would like to change "b_3" to "b_2":

> x$matrices$A$labels[3,4] <- "b_2"
Error: Right-hand side of assignment operator has illegal value FullMatrix, SymmMatrix, FullMatrix, and FullMatrix

Why does this not work?

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No user picture. WuandMu Joined: 06/15/2015

Constraining mxAlgebra across submodels

Hi,

This is actually quite a quick question and the title says most of it already.
Anyway, is there anyway to constrain mxAlgebra objects across multiple submodels?

I would like to constrain estimated heritability of two separate twin models to be the same while allowing each submodel to have separate parameter estimations.

Unfortunately I was unable to find a way to do so. I have tried mxConstraint(modelA.algebra1==modelA.algebra2) but that seemed not to work.

I would be thankful for any reply!

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No user picture. jkarch Joined: 03/15/2011

Recommended stable OpenMx Version

I am a bit confused what the latest stable OpenMx Version is. The last news announcement is for 2.0.1, the install script installs 2.2.4 on my linux supercomputer and fails to install 2.2.2 on my mac laptop (see http://openmx.psyc.virginia.edu/thread/3997).
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Picture of user. carey Joined: 10/19/2009

Funky confidence intervals

Are the default confidences intervals for mxCI 95% or 90%? Or is there something funky in the documentation of mxCI? My understanding of a 95% confidence interval is that it is equivalent to a two-tailed test with alpha = .05. That is, it delimits the 2.5% most extreme values at the low end and the 2.5% most extreme values at the high end, leaving the 95% most likely values between the confidence intervals.

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Picture of user. carey Joined: 10/19/2009

mxFitFunctionAlgebra question

Attached are two outputs, one from OpenMx 2.0.1.4157 using OS X on a Mac and the other from OpenMx 2.2.2 on Red Hat Linux. In both situations the models converge when I use mxExpectationNormal and mxFitFunctionML. But when I manually set the fit function to -log(likelihood) using mxFitFunctionAlgebra, mxRun crashes in both operating systems (albeit with different errors).
Am perplexed.
Greg