Structural equation models with R

-----Original Message-----
From: r-help-bounces at stat.math.ethz.ch 
[mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Andr? 
TavaresCorr?a Dias
Sent: Wednesday, March 09, 2005 9:53 AM
To: r-help at stat.math.ethz.ch
Subject: [R] Structural equation models with R

Hello useRs,
I`m running structural equation models with R, but for one of 
my models the below error message apears. I`m trying to 
change startvalues but without success. The manual for sem 
package did not help me. Does anyone knows how to change 
startvalues for iteration in sem package? Or it can be 
another problem with the model?

Error in startvalues(S, ram, debug = debug, tol = start.tol) : 
subscript out of bounds

The model (with three latent variables: 'reg','folha','solo'))

model.com=matrix(c(
'ridos>dendos',	'a1',	NA,
'ridos>reg',	'a2',	NA,
'ridos>folha',	'a3',	NA,
'ridos>solo',	'a4',	NA,
'ridos>raiz',	'a5',	NA,
'dendos>litter',	'a6',	NA,
'dendos>reg',	'a7',	NA,
'litter>reg',	'a8',	NA,
'folha>reg',	'a9',	NA,
'solo>reg',		'a10',	NA,
'raiz>reg',		'a11',	NA,
'raiz>solo',	'a12',	NA,
'folha>solo',	'a13',	NA,
'reg>denjov',	'l1',	NA,
'reg>riqjov',	'l2',	NA,
'folha>nfolha',	'l3',	NA,
'folha>pfolha',	'l4',	NA,
'solo>nsolo',	'l5',	NA,
'solo>psolo',	'l6',	NA,
'riqjov<>riqjov',	'e1',	NA,
'denjov<>denjov',	'e2',	NA,
'litter<>litter',	'e3',	NA,
'riqdos<>riqdos',	'e4',	NA,
'dendos<>dendos',	'e5',	NA,
'raiz<>raiz',	'e6',	NA,
'nsolo<>nsolo',	'e7',	NA,
'psolo<>psolo',	'e8',	NA,
'nfolha<>nfolha',	'e9', NA,
'pfolha<>pfolha',	'e10',	NA,
'reg<>reg',		NA,	1,
'solo<>solo',	NA,	1,
'folha<>folha',	NA,	1),
ncol=3, byrow=TRUE)

obs.vars.com=c('riqjov','denjov','litter','riqdos','dendos','raiz',
'nsolo','psolo','nfolha','pfolha')

sem.com=sem(model.com,S.com,30,obs.vars.com)

-------------------------------
Andr? Tavares Corr?a Dias
Laborat?rio de Ecologia Vegetal
Departamento de Ecologia - IB
Universidade Federal do Rio de Janeiro
Ilha do Fund?o, CCS
Rio de Janeiro, RJ. Brasil
CEP 21941-590    CP 68020
Tel. (21)2562-6377

-----Original Message-----
From: Andr? TavaresCorr?a Dias [mailto:atcdias at biologia.ufrj.br] 
Sent: Thursday, March 10, 2005 6:14 AM
To: John Fox
Cc: r-help at stat.math.ethz.ch
Subject: RE: [R] Structural equation models with R

Dear John,
Thanks very much! I don?t know how I didn?t see this before. 
I checked a thousand of times.... 

There is one more thing that I 
can not understand. What are the possible reasons for 
problems on calculation of confidence interval for RMSEA? For 
the same model I sent before (after correction of the 
variable name) the lower CI output was NA:

Model Chisquare =  10.824   Df =  13 Pr(>Chisq) = 0.62558
 Goodness-of-fit index =  0.91656
 Adjusted goodness-of-fit index =  0.76895
 RMSEA index =  0   90 % CI: (NA, 0.15652)
 BIC =  -60.425

I have other models with the same behavior, even when the 
estimative of RMSEA is different from zero.

Model Chisquare =  15.165   Df =  14 Pr(>Chisq) = 0.367
 Goodness-of-fit index =  0.89038
 Adjusted goodness-of-fit index =  0.71811
 RMSEA index =  0.053558   90 % CI: (NA, 0.19141)
 BIC =  -61.564