[R] nlsystemfit: Errors with reproducing the manual example

[Federico Tamagni]

Hi everybody, I'm a newbye with lots of problems :). I'm trying to use 
nlsystemfit, but I recieve two error messages whose origin that I don't 
understand.

1) When I try to reproduce the example reported in the systemfit package 
manual, that is

library( systemfit )
data( ppine )
 hg.formula <- hg ~ exp( h0 + h1*log(tht) + h2*tht^2 + h3*elev + h4*cr)
dg.formula <- dg ~ exp( d0 + d1*log(dbh) + d2*hg + d3*cr + d4*ba )
labels <- list( "height.growth", "diameter.growth" )
inst <- ~ tht + dbh + elev + cr + ba
start.values <- c(h0=-0.5, h1=0.5, h2=-0.001, h3=0.0001, h4=0.08,
+ d0=-0.5, d1=0.009, d2=0.25, d3=0.005, d4=-0.02 )
model <- list( hg.formula, dg.formula )
model.ols <- nlsystemfit( "OLS", model, start.values, data=ppine, 
eqnlabels=labels )

then I get the following messages:
/
The following object(s) are masked _by_ .GlobalEnv :

         dg hg


        The following object(s) are masked from data ( position 3 ) :

         ba cr dbh dg elev hg smi tht

Error in array(x, c(length(x), 1), if (!is.null(names(x))) list(names(x),  :
        dim<- : invalid first argument
/


2) When I try to do something similar on my own data (called R_manuf and 
containing 3 columns named va98, ts98 and gom98) with the code

library(systemfit)
dati <- read.table("R_manuf",header=T,na.strings="nan")
attach(dati)

y1      <-  va98/ts98 - 1;
y2      <-  gom98 - va98;
eq1.formula  <-  y1.98 ~ a1*ts98^(b1-1) ;
eq2.formula  <-  y2.98 ~ a2*ts98^b2 ;
labels <- list("eq1", "eq2" );
start.values <- c(a1=-0.5,  b1=1.02, a2=-0.8, b2=0.9 );
model <- list( eq1.formula, eq2.formula);
model.ols <- nlsystemfit( "OLS",  model,  start.values,  
eqnlabels=labels  );
print(model.ols);

then I get a different error message: /

Error in eval(expr, envir, enclos) : incorrect number of subscripts on 
matrix/


Thanks for your help,


Federico





-- 
Federico Tamagni, PhD student
LEM - Laboratory of Economics and Management
Scuola Superiore Sant'Anna, Pisa, Italy
Phone: (+39)-050-883341 
Fax: (+39)-050-883344
email: f.tamagni at sssup.it
website: https://mail.sssup.it/~f.tamagni/