OpenMx Help
brandmaier
Joined: 02/04/2010
Standardized estimates under equality constraints
I was wondering how OpenMx treats standardized estimates under equality constraints.
I ran a linear latent growth curve model in OpenMx and constrained all residual variances to be equal. Not surprisingly, they all get to be the same unstandardized estimate. However, OpenMx reports only a single standardized estimate for the residual, which happens to be the one associated with the first observation. Even if the unstandardized estimates are constrained to be equal, the unstandardized ones need not be and in reality seldom are the same.
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brandmaier
Joined: 02/04/2010
Sticky issue: Problems with tar
When installing OpenMx on OSX 10.9.2, I ran into the following error:
"tar: Option --delete is not supported"
Particularly, this error happens after successful compilation when the npsol-related files are deleted from the resulting gzip file. On my machine, tar does in fact not support the "--delete" option. For Mac users, MacPorts provides gnutar, which does the job. However, with the default path of MacPorts, one needs to explicitly create another symlink:
sudo ln -s /opt/local/bin/gnutar /usr/bin/gnutar
and change line 268 in the Makefile to:
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siti nur azizah
Joined: 03/12/2014
modified model
hi, I am a beginner using Mx open packages, so I do not quite understand. I have run my program. output is given as attached.
The value of RSMEA, CFI and TLI its very ugly because its value doesn't meet either criteria . What can I do in advance to improve the model?
thank you.
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mverdam
Joined: 02/04/2014
Referring to an OpenMx matrix in the OpenMx environment
I'm trying to run a model in which I have several matrices that should contain the same parameter estimates (they overlap partly). I know I can use labels or mxConstraint to put equality constraints on parameter estimates, but I was wondering if it is also possible to refer directly to the parameter estimates of a matrix in other parts of the OpenMx environment. For example, I have tried to build an mxAlgebra that refers to the parameter estimates of an mxMatrix by using:
mxAlgebra(expression=cbind(Model.mxMatrix[,i],Model.mxMatrix[,j]), name="part_mxMatrix")
mverdam
Joined: 02/04/2014
Avoid default abort when error occurs
I'm trying to run multiple SEM-models within a loop (i.e., for simulation purposes), but am experiencing some problems when a model does not run properly (i.e., objective function returns NaN). The default action is to abort and display an error message, which results in aborting the whole loop.
I am looking for a way to make it possible to make sure the loop will continue when one of the models is not returning a result (and of course, I would also like to save the non-result in some way).
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fife
Joined: 07/01/2010
Computing R squared with missing data
This may be an easy question, but I can't think of the answer. I've built a regression model (predicting Y) with two independent variables (X and Z). I want to compute R^2. Is that built into the model somehow? If not, any ideas on how to compute it? Here's the model I have:
multiRegModel <- mxModel("Multiple Regression, All Variables",
type="RAM",
manifestVars=c("x", "y", "z"),
# variance paths
mxPath(
from=c("x", "y", "z"),
arrows=2,
free=TRUE,
values = c(.5, .5, .5),
labels=c("varx", "residual", "varz")
),
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Julia
Joined: 03/29/2012
Adding new algebras in submodels and constraining them
Hi.
I am running a bivariate moderation model and would like to set some constraints in order to test for some nonlinear effects. I am struggling though with adding new algebras into submodels (with subsequent equating them). Let's say that I specify
pathAm <- mxMatrix(name = "am", type = "Lower", nrow = nv, ncol = nv, free=T, labels = c("amM","amC","amU"), values=pathVal)
pathCm <- mxMatrix(name = "cm", type = "Lower", nrow = nv, ncol = nv, free=T, labels = c("cmM","cmC","cmU"), values=pathVal)
a9mike
Joined: 06/28/2013
Confidence Intervals
I'm not sure the best way to get confidence intervals for my estimates. I'm doing a bifactor model with a large dataset (HRS) with lots of missing data, and the mxCI are taking impossibly long (days long).
Anyone have suggestions? Would bootstrapping be faster? If so, what would that script look like? (I've never bootstrapped before)
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neale
Joined: 07/31/2009
International Workshop on Statistical Genetic Methods for Complex Human Traits. March 3-7, Boulder Colorado
This workshop will be taught at the Millennium Harvest Hotel in Boulder Colorado, March 3-7 2014, and will use OpenMx extensively. Those interested in a general education in OpenMx use would be well-served by the course, at the expense of learning about genetics and modeling data from twins and other relatives.
http://www.colorado.edu/ibg/content/march-3-march-7-2014-2014-international-workshop-statistical-genetic-methods-human-complex
cuttance
Joined: 01/20/2014
OpenMx in the Cloud
I’m looking to integrate MSEM (one of: OpenMx, MPlus, LISREL, etc) into an application I am developing for schools on a .NET Microsoft Azure Cloud platform — multiple schools will access the application simultaneously, and the application will call the MSEM modelling unit to estimate a specific model and return the estimates to a database for benchmarking purposes.
Would I need to run OpenMx inside a VM, or is there a server version? Can multiple instances of OpenMx run inside the same VM? or Would we need to run multiple VMs, each for an instant of OpenMx?
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