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mxCompare function

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No user picture. krzysiek Joined: 09/05/2013
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Fit Functions

Hi,

I tried to compare two CFA models using the mxCompare function. Unfortunately, I received the message:

Error in refSummary$modelName : $ operator is invalid for atomic vectors

At first I thought I had some code error but I run an example located in the help for mxCompare function, that is:

data(demoOneFactor)
manifests <- names(demoOneFactor)
latents <- c("G1")
model1 <- mxModel(model="One Factor", type="RAM",
manifestVars = manifests,
latentVars = latents,
mxPath(from = latents, to=manifests),
mxPath(from = manifests, arrows = 2),
mxPath(from = latents, arrows = 2, free = FALSE, values = 1.0),
mxData(cov(demoOneFactor), type = "cov", numObs = 500)
)

fit1 <- mxRun(model1)

latents <- c("G1", "G2")
model2 <- mxModel(model="Two Factor", type="RAM",
manifestVars = manifests,
latentVars = latents,
mxPath(from = latents[1], to=manifests[1:3]),
mxPath(from = latents[2], to=manifests[4:5]),
mxPath(from = manifests, arrows = 2),
mxPath(from = latents, arrows = 2, free = FALSE, values = 1.0),
mxData(cov(demoOneFactor), type = "cov", numObs=500)
)
fit2 <- mxRun(model2)

mxCompare(fit1, fit2)

In this situation, I received the same error message.
Error in refSummary$modelName : $ operator is invalid for atomic vectors
What's wrong?

best regards,
Krzysztof

Replied on Fri, 11/10/2017 - 08:12
No user picture. AdminJosh Joined: 12/12/2012

Which version of OpenMx are you using? What is the output of mxVersion() ? Here is what I get for your example,


> mxCompare(fit1, fit2)
base comparison ep minus2LL df AIC diffLL diffdf p
1 One Factor 10 -3660.597 5 -2.606207 NA NA NA
2 One Factor Two Factor 10 -2456.240 5 1201.750901 1204.357 0 NA

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Replied on Fri, 11/10/2017 - 11:46
No user picture. krzysiek Joined: 09/05/2013

The output of mxVersion() is

OpenMx version: 2.6.9 [GIT v2.6.9]
R version: R version 3.2.5 (2016-04-14)
Platform: x86_64-w64-mingw32
Default optimiser: SLSQP

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Replied on Fri, 11/10/2017 - 14:39
No user picture. krzysiek Joined: 09/05/2013

Yes, I upgraded 2.8.3.

> mxVersion()
OpenMx version: 2.8.3 [GIT v2.8.3]
R version: R version 3.4.2 (2017-09-28)
Platform: x86_64-w64-mingw32
Default optimiser: CSOLNP
NPSOL-enabled?: No
OpenMP-enabled?: No

But it doesn't help.

Krzysztof

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Replied on Fri, 11/10/2017 - 16:01
Picture of user. AdminRobK Joined: 01/24/2014

I'm also curious to see a complete script that demonstrates the issue. Are you loading a saved R workspace, or any .RData file, before you encounter this issue? Also, please make sure your script makes clear the exact order in which packages are loaded into R's workspace.

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Replied on Tue, 11/14/2017 - 11:22
Picture of user. AdminNeale Joined: 03/01/2013

IMO, we don't do a good enough job telling users that models will likely have to be re-run with a new version of OpenMx, i.e., mxModels in .Rdata files will likely *not* be compatible with a new version. It would be better if we could reliably tell users when that would be necessary - because we have changed the structure of mxModel objects to the point of incompatibility with prior versions. We might even consider using our upgrade numbering system to validate what would and what would not work from a prior version - version changes in the z of version x.y.z would not require re-running models, whereas changes of x or y would require it. That is not, I think, the way we use it now. This change would, of course, require a test...

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