This is a bug. The `prior.weights' element of the the faked `gam' object (i.e. `test$gam$prior.wieghts' below) has been set to the varIdent() variance function, rather than the weights that this eventually represents. I'll fix this for the next patch release, (as soon as I get any time to do research rather than doing dummy runs of describing how good the research might be that I would be doing if I was doing it instead of practicing writing about it).
In the meantime if you do something like: test$gam$prior.weights <- rep(1,length(Z)) then summary(test.gam) will work, but you should ignore the reported r^2. best, Simon >- Simon Wood, Mathematical Sciences, University of Bath, Bath BA2 7AY >- +44 (0)1225 386603 www.maths.bath.ac.uk/~sw283/ On Tue, 6 Jun 2006, Highland Statistics Ltd. wrote: > Hello, > > Why would I get an error message with the following code for gamm? I > want to fit the a gam with different variances per stratum. > > > library(mgcv) > library(nlme) > > Y<-rnorm(100) > X<-rnorm(100,sd=2) > Z<-rep(c(T,F),each=50) > > test<-gamm(Y~s(X),weights=varIdent(form=~1|Z)) > > summary(test$lme) #ok > > summary(test$gam) > > Gives an error message: > Error in inherits(x, "data.frame") : dim<- : dims [product 100] do > not match the length of object [0] > > > All the other output seems to be ok: > > > > summary(test$lme) > Linear mixed-effects model fit by maximum likelihood > Data: strip.offset(mf) > AIC BIC logLik > 299.9468 312.9727 -144.9734 > > Random effects: > Formula: ~Xr.1 - 1 | g.1 > Structure: pdIdnot > Xr.11 Xr.12 Xr.13 Xr.14 Xr.15 > StdDev: 0.0001073404 0.0001073404 0.0001073404 0.0001073404 0.0001073404 > Xr.16 Xr.17 Xr.18 Residual > StdDev: 0.0001073404 0.0001073404 0.0001073404 1.045916 > > Variance function: > Structure: Different standard deviations per stratum > Formula: ~1 | Z > Parameter estimates: > TRUE FALSE > 1.0000000 0.9721987 > Fixed effects: y ~ X.0 - 1 > Value Std.Error DF t-value p-value > X.0(Intercept) 0.04426102 0.1041540 98 0.4249573 0.6718 > X.0s(X)Fx1 -0.01053900 0.1039558 98 -0.1013796 0.9195 > Correlation: > X.0(I) > X.0s(X)Fx1 0.002 > > Standardized Within-Group Residuals: > Min Q1 Med Q3 Max > -1.96955692 -0.81101014 0.07004034 0.72528662 2.44244302 > > Number of Observations: 100 > Number of Groups: 1 > > > > > > Kind regards, > > Alain > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
