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how to test is a model is a RAM model

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Picture of user. tbates Joined: 07/31/2009
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OpenMx General Help

The new 2-part objectives in OpenMx mean an older method for testing if a model is a RAM model don't work

I used to say this:

(isS4(obj) && is(obj, "MxModel") && class(obj$objective)[1] == "MxRAMObjective")

What code do people recommend for backward (and preferably forward compatible testing of model type? Do we need to add a type= field to MXModel?

best, tim

Replied on Tue, 03/05/2013 - 16:25
Picture of user. Ryne Joined: 07/31/2009

Haven't gotten this far in the Expectation/Fit split, but it'll likely be as simple as replacing references to objective to references to expectation. I'll look into this more as we get closer to beta release.

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Replied on Tue, 03/05/2013 - 17:08
Picture of user. tbates Joined: 07/31/2009

maybe an OpenMx supported function to maintain a robust backward compatible test for users. Perhaps allowing


omxModelType <- function(obj, typeList= (c("RAM", "LISREL", "MATRIX"){
# test each requested item
}

# typically called with one test case
if(omxModelType(m1, "RAM"){
}

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Replied on Thu, 03/07/2013 - 17:12
Picture of user. mhunter Joined: 07/31/2009

Your same code would work if you replace $objective with $expectation, and "MxRAMObjective" with "MxExpectationRAM". I'm not sure if that's the best practice, but it would work currently.

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Replied on Thu, 03/07/2013 - 17:46
Picture of user. tbates Joined: 07/31/2009

this fails for current OpenMx.

class(obj$expectation)[1] == "MxExpectationRAM"

so the "good today, great tomorrow" test is

isModel = isS4(obj) & is(obj, "MxModel")
isRAM_Model = (class(obj$objective)[1] == "MxRAMObjective" | class(obj$expectation)[1] == "MxExpectationRAM")
isModel & isRAM_Model

:-)

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Replied on Thu, 03/07/2013 - 18:16
Picture of user. mhunter Joined: 07/31/2009

This passes with the current *source* build.

(isS4(obj) && is(obj, "MxModel") && class(obj$expectation)[1] == "MxExpectationRAM")

where obj is a fitted OpenMx model. I used demo/LatentGrowthCurveModel_PathRaw.R as a test case.


source("demo/LatentGrowthCurveModel_PathRaw.R")
obj <- growthCurveFit
(isS4(obj) && is(obj, "MxModel") && class(obj$expectation)[1] == "MxExpectationRAM")

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