OpenMx Help
pehkawn
Joined: 05/24/2020
Combining two single factor models into a two-factor model
Based on the [two-factor model](https://vipbg.vcu.edu/vipbg/OpenMx2/docs//OpenMx/latest/FactorAnalysis_Path.html#two-factor-model ) and [joint ordinal-continuous model](https://vipbg.vcu.edu/vipbg/OpenMx2/docs//OpenMx/latest/Ordinal_Path.html#joint-ordinal-continuous-data) examples in the documentation, I tried creating two single-factor models (one continuous and one ordinal), which I tried to combine in a new model. In the new model essentially just tried to add a covariance path between the latent variables.
pehkawn
Joined: 05/24/2020
Effects coding method in CFA
I am trying to run a CFA where one latent variable is regressed on four manifest variables. I am trying to constrain the pattern coefficients ($\lambda$) mean to equal one, according to [Kline's (2015, p. 200)](https://www.guilford.com/books/Principles-and-Practice-of-Structural-Equation-Modeling/Rex-Kline/9781462523344) *effects coding method*:
$$ \frac{\lambda_1 + \lambda_2 + \lambda_3 + \lambda_4}{4} = 1 $$
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pehkawn
Joined: 05/24/2020
Interactions in latent variable models
I am fairly new to SEM in general, and I've been trying to figure out the best approach to modeling interaction effects between latent variables in OpenMx.
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cjvanlissa
Joined: 04/10/2019
CRAN test failure
Dear OpenMx team,
As I'm sure you're aware, OpenMx and its dependencies have been scheduled for archival from CRAN. I was just wondering whether a response is underway on your side?
Hope you are all well; sincerely,
Caspar
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dr.gw
Joined: 09/09/2021
Error Code 6
Hi,
I have written up a script using a RAM formulation and so is maximizing the likelihood using the mxExpectationRAM() function with raw data. I have got a warning message with status code 6 when I ran my model in openMX. The model was identified, which was tested by mxCheckIdentification().
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lf-araujo
Joined: 11/25/2020
Cascade / stealth model script example for OpenMx
Hi all,
I hope everyone is healthy.
I have been looking into extended family design, starting with S Medland papers [1,2]. Also, M Keller have some basic scripts [here](http://www.matthewckeller.com/html/cascade.html) which does not specify Medland's model completely, nor the Stealth model. My question:
- Does anyone care to share a script example for training purposes on either/or models? Or point to where I can find these?
Many thanks,
Luis
**Edit**:
hansfredriksunde
Joined: 12/10/2021
Wrong estimates when using definition variables and WLS
Hi everyone!
ssciarra
Joined: 01/08/2021
Error only occurring on Amazon linux instance
I am trying to run simulations on an Amazon linux instance and get the following error when I use `mxAutoStart()` to generate starting values :
library(devtools)
#install_github("sciarraseb/nonlinSims", dependencies = T, force=T)
library(easypackages)
library(nonlinSims)
library(parallel)
library(tidyverse)
library(OpenMx)
library(data.table)
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MaximilianStefan
Joined: 12/04/2018
Performance regression of OpenMx for simple CFA model
I specified a simple CFA model (5 factors, 20 Items each), simulated data from it (25 observations for each parameter) and fitted the model in lavaan and OpenMx. Surprisingly, OpenMx takes about 100x longer to fit the model (same starting values in lavaan and OpenMx). I attached an MWE.
The results on my machine are
lavaan: 0.16 seconds/31 iterations
OpenMx: 13.2 seconds/135 iterations
pgok
Joined: 11/13/2019
Estimating a non-linear model in OpenMx
Hi, I'm pretty new to OpenMx, having only used it off-and-on over the past few years. That said, I am pretty interested in using it more, especially given the multilevel modeling capabilities (e.g., as discussed in Pritkin et al., 2017). However, my question isn't about the multilevel modeling capabilities, my question is about fitting non-linear models.
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