[R] Help with SEM: "Error in 1:m : NA/NaN argument"

[John Fox]

Dear Annalisa,

I was unable to load either of the data sets that you provided, obtaining
the following message:

---------- snip --------

> load(file.choose())
Error: bad restore file magic number (file may be corrupted) -- no data
loaded
In addition: Warning message:
file 'CC32.Rdata' has magic number '"T1" '
  Use of save versions prior to 2 is deprecated

---------- snip --------

I assume from what you did that all of the exogenous variables in the model
are observed variables in the covariance matrix in CC32; otherwise it
wouldn't make sense to specify them as fixed.x. 

Some other comments: You've named a number of parameters "0", with the side
effect that they are all constrained equal. One can do this, but I doubt
whether you intended it. I'd encourage you to use specifyEquations(), which
I think is less error-prone, rather than specifyModel(), and to pass the
data, rather than a covariance matrix, to sem(). As well, I'd be concerned
about a model that really required 100000 iterations to converge, and wonder
why you're using the GLS objective function.

I hope this helps,
 John

-----------------------------------------------
John Fox, Professor
McMaster University
Hamilton, Ontario, Canada
http://socserv.socsci.mcmaster.ca/jfox/



> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of AnnalisaStacchini
> Sent: Monday, February 10, 2014 1:08 PM
> To: r-help at r-project.org
> Subject: [R] Help with SEM: "Error in 1:m : NA/NaN argument"
> 
> Hi, I am trying to fit a SEM model (the ram specification of the model,
> along with the estimated polycoric VCmatrix (CC32), is attacched), but
> I get the following error message: "Error in 1:m : NA/NaN argument"I
> did not find any help on internet, so I tried to understend what is
> going wrong calling: getAnywhere(sem.default) and reproducing the
> sem.default function step by step.I found that the problem arises from:
>     n.fix <- length(fixed.x)
> 
>     if (!is.null(fixed.x)) {
> 
>         for (i in 1:n.fix) {
> 
>             for (j in 1:i) {
> 
>                 ram <- rbind(ram, c(2, fixed.x[i], fixed.x[j],
> 
>                   0, S[fixed.x[i],
> fixed.x[j]]))
> 
>             }
> 
>         }
> 
>     }
> 
>     m <- max(ram[, c(2, 3)])
> Indeed, if I run just:
> for (i in 1:n.fix) {for (j in 1:i) {G<-c(2, fixed.x[i], fixed.x[j],
> 0, S[fixed.x[i], fixed.x[j]]) }
> I get only this (G=):  "2"       "Autunno" "Autunno" "0"       "1"
> But I still cannot understand what is wrong.The code I used is:
> library(sem)CLB<-classifyVariables(Mod.Bus)
> 
> fisse<-as.character(CLB$exogenous)Business32<-sem(Mod.Bus,
> S= as.matrix(CC32), N<- 16029, fixed.x=fisse,objective= objectiveGLS,
> maxiter=100000)
> 
> Can anybody help me please?Any suggestion will be truly
> appreciated.Annalisa
> 
> 
> Model ram specific.docx (21K)
> <http://r.789695.n4.nabble.com/attachment/4685052/0/Model%20ram%20speci
> fic.docx>
> CC32.Rdata (20K)
> <http://r.789695.n4.nabble.com/attachment/4685052/1/CC32.Rdata>
> C32.Rdata (17K)
> <http://r.789695.n4.nabble.com/attachment/4685052/2/C32.Rdata>
> 
> 
> 
> 
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