OpenMx Help

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Picture of user. brandmaier Joined: 02/04/2010

Error in summary()

Hi,

I created a model without any free parameters. I'd like to run the model to obtain the likelihood of some data under this model. The model runs fine but summary() returns the error that the comparison "matrix == nameA" is valid only for atomic and list. It seems that summary() is missing a check for empty lists of free parameters. This is the traceback():

8: eval(expr, envir, enclos)
7: eval(e, x, parent.frame())
6: subset.data.frame(ptable, matrix == nameA, select = "row", drop = TRUE)
5: subset(ptable, matrix == nameA, select = "row", drop = TRUE)

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No user picture. CharlesD Joined: 04/30/2013

excessive memory usage when definition variables vary substantially

Hi. I've been doing some work on a package to overlay openmx and manage continuous time SEM models. Everything is working great but I am quite stuck with what seems to be some sort of memory management issue with openmx. I've spoken with Tim Brick regarding this previously, but thought I'd put it up here for all to see :)

Posted on
No user picture. lind0r Joined: 12/27/2013

Unable to reproduce MASEM results from a published study

Hi,

I'd like to reproduce the meta-analytic structural equation modeling (MASEM) results from this study:
soonang[dot]com/wp-content/uploads/2011/04/2007-MISQ-Ang1.pdf

I used the correlation matrix (Table 3, p. 559) as input and specified the paths according to Figure 2 (p. 560).
Additionally, I set the number of observations to 701 (p. 558).
The full openMx code is attached.

The openMx output for the parameter estimates fits the values in Figure 2 quite well.
However, the openMX fit statistics are quite different from the ones in the paper.

Posted on
Picture of user. Daria Henning Joined: 12/18/2013

Error: The observed covariance matrix is not a symmetric matrix

I've got the following error message when fitting a one factor model:
Error: The observed covariance matrix is not a symmetric matrix

Below is the code. When looking at the cov matrix it looked quite summetrical to me...

Does somebody have suggestions?

Thanks a lot in advance.

obsnames = c("intrthought","recdreams","flashbk","emoreact","physreact","avoidthou","avoidremind","amnesia","lossinter","detach","restrAff","foreFut","SleepDis","Irritab","DifConcentr","Hypervigilance","ExaggStartle")

obslabels = list (obsnames,obsnames)

values = c(1.00,
.70, 1.00,

Posted on
Picture of user. Daria Henning Joined: 12/18/2013

NPSOL returned a non-zero status code 6. The model does not satisfy the first-order optimality conditions to the required accur

Hi,

Finally I managed to fit a longitudinal one- factor model but now I received the following warning message:

NPSOL returned a non-zero status code 6. The model does not satisfy the first-order optimality conditions to the required accuracy, and no improved point for the merit function could be found during the final linesearch (Mx status RED)

As I am a beginner in OpenMX suggestions and any help is very welcome.
Thanks in advance!

############################################################
This is my code:
############################################################

Posted on
Picture of user. Daria Henning Joined: 12/18/2013

Error: unexpected ',' in "

Hi,

I am getting a bit lost with the following error below. I frequently get it when runnning the specified data matrices. Sometimes the error pops up at different points. As I really cannot see any typos etc. I am starting to get quite annoyed about it.

Does somebody has any suggestions?

I would appreciate it very much!
Thanks already.

title = " Factor model Personality traits at 3 timepoints"
> obs = mxData(observed = akkercov, type = 'cov', means = petrmeans, numObs = 290)
> matrixL = mxMatrix(
+ type = 'Full',
+ nrow = 15,
+ ncol = 3,
+ free = (TRUE,FALSE,FALSE,

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Picture of user. Daria Henning Joined: 12/18/2013

Error: The observed covariance matrix is not a positive-definite matrix

Hi all,

I want to fit a one fatcor longitudinal model at three measuremet time points based on an observed covariance/correlation matrix from an published article. Unfortunately I get the following error message when running the obs function, see below.

This is the error:
Error: The observed covariance matrix is not a positive-definite matrix

It would be great if somebody could help with some suggestions!

This is the beginning of the code:

## create observed covariance matrix

obsnames = c("extrT1","beneT1","conscT1","emostT1","imagT1",

Posted on
No user picture. xander Joined: 11/09/2013

Specifying a Mediation Model in OpenMx using metaSEM

Hello All,

First of all thank you for your hard work over the years to provide us with unique ways to combine meta-analytic principles with SEM--and providing a conduit to do this in R. My research team and I really appreciate it.

I am doing a two stage MASEM with the metaSEM package, and am having some difficulty specifying a mediation analysis in the A/Smatrix. I have four variables: w,x,y,z. And my linear equations are as follows:

X ~ W + e
Z ~ W + e
Y ~ W + X + Z + e

I would like to see if X or Z (or X and Z) mediate the relationship between W and Y.

Posted on
No user picture. Samaneh2013 Joined: 06/19/2013

Installing OpenMx on R 2.15

I have a difficulty of installing OpenMx in version 2.15 and version 3, I have types library (OpenMx) but this gives a warning sign!

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No user picture. mari Joined: 09/26/2013

Does OpenMx support SEM analysis using ordinal/binary indicators and sampling weights

Hi,

I'd like to know if it's possible to estimate a sem model with ordinal and binary indicators using a WLS estimator based on the raw data including the sampling weights. The data set contains a weight column with an individual weight for each case and I don’t need multilevel modeling.

I am currently using the R package lavaan for SEM analysis. As lavaan does not support this functionality, I’m considering changing to OpenMx.