lavaan or sweave problem

[Martina]

I am fitting the example of Bollen on political democracy with the following program:

 

library(lavaan)

library(semPlot)

 

bollen.cov = matrix(c(

  6.89, 6.25, 5.84, 6.09, 5.06, 5.75, 5.81, 5.67, 0.73, 1.27, 0.91,

  6.25,15.58, 5.84, 9.51, 5.6 , 9.39, 7.54, 7.76, 0.62, 1.49, 1.17,

  5.84, 5.84,10.76, 6.69, 4.94, 4.73, 7.01, 5.64, 0.79, 1.55, 1.04,

  6.09, 9.51, 6.69,11.22, 5.7 , 7.44, 7.49, 8.01, 1.15, 2.24, 1.84,

  5.06, 5.6,  4.94, 5.7 , 6.83, 4.98, 5.82, 5.34, 1.08, 2.06, 1.58,

  5.75, 9.39, 4.73, 7.44, 4.98,11.38, 6.75, 8.25, 0.85, 1.81, 1.57,

  5.81, 7.54, 7.01, 7.49, 5.82, 6.75,10.8 , 7.59, 0.94, 2   , 1.63,

  5.67, 7.76, 5.64, 8.01, 5.34, 8.25, 7.59,10.53, 1.1 , 2.23, 1.69,

  0.73, 0.62, 0.79, 1.15, 1.08, 0.85, 0.94, 1.1,  0.54, 0.99, 0.82,

  1.27, 1.49, 1.55, 2.24, 2.06, 1.81, 2   , 2.23, 0.99, 2.28, 1.81,

  0.91, 1.17, 1.04, 1.84, 1.58, 1.57, 1.63, 1.69, 0.82, 1.81, 1.98),

                    nrow =11,ncol=11)

 

rownames(bollen.cov) = c("y1","y2","y3","y4","y5","y6","y7", "y8","x1","x2","x3")

colnames(bollen.cov) = c("y1","y2","y3","y4","y5","y6","y7", "y8","x1","x2","x3")

 

model <- '

# latent variables

ind60 =~ x1 + x2 + x3

dem60 =~ v1 *y1 + v2* y2 + v3 *y3 + v4 *y4

dem65 =~ v1 *y5 + v2* y6 + v3 *y7 + v4 *y8

# regressions

dem60 ~ ind60

dem65 ~ ind60 + dem60

# residual covariances

y1 ~~ y5

y2 ~~ y4 + y6

y3 ~~ y7

y4 ~~ y8

y6 ~~ y8

'

 

fit <- sem(model,sample.nobs = 75,sample.cov=bollen.cov)

 

 

Sometimes this works fine but sometimes I get

 

>

> fit <- sem(model,sample.nobs = 75,sample.cov=bollen.cov)

Error in sem.semmod(model, sample.nobs = 75, sample.cov = bollen.cov) :

  S and data cannot both be missing

 

although the covariance matrix is given???

 

And when I put this program into sweave code to create a dynamic report I also get this error?

 

I had also a problem when I was using the sem package together with sweave: I had to put the model specification in a file and read it with specifyModel, but there is nothing similar in lavaan , is there?

 

 

Thanks for any help!

Martina

 

 

[Jan Lammertyn]

Hi Martina,

From the error it looks like you are using the sem function from the sem-package instead of lavaan. Are you cross-loading both packages?

Kind regards,

Jan

[Martina]

I did indeed load the sem-package too because of another example.

The problem is now solved by using lavaan::sem in the program.

It is not a good idea to use the same name for that funcion in lavaan...

 

[신종화]

It is the namespace issue, isn't? Sharing the same name in building a function is the issue beyond a developer's manner with contributed packages. Besides, the function names, like sem or cfa does not belong to anyone in the SEM communities. I support lavaan::sem as well as sem::sem. The users should know their internal differences.

Jong-Hwa

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