[R] SEM specify RAM model

John Fox jfox at mcmaster.ca
Fri Jun 6 08:17:00 CEST 2014

Dear George,

It's not entirely clear to me what you're trying to do, and where the loop comes in. 

As has already been suggested, you can store the model specification in a file or files. Also, the "RAM" form of the model can be specified as a character matrix, a numeric matrix, or a "semmod" object. These are documented in ?sem. You could look at the internal structure of a "semmod" object produced by specifyEquations() or specifyModel() to see how it works.

I hope that this helps,

John Fox, Professor
McMaster University
Hamilton, Ontario, Canada
On Wed, 4 Jun 2014 15:45:44 +0100
 George Parish <george_parish at hotmail.co.uk> wrote:
> Dear all,
> I am trying to create multiple SEM models in a loop - so that if I change the data they can easily be re-created rather than re-creating each RAM model line by line - therein lies my problem.
> I have a dataframe set out as follows1                 Duration -> RC1      cov1 -0.2563002                      MMSE -> RC1      cov2 -0.0309003                RC1 -> Aggression      npi1  0.2310004                    RC1 -> Apathy      npi2  0.1043005             RC1 -> Disinhibition      npi3  0.279800 ...
> the specifyModel() and specifyEquations() methods need you to manually input each line individually. Can I simply supply the SEM method with a matrix like the one I have above?
> Thanks,George 		 	   		  
> 	[[alternative HTML version deleted]]
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