Generally you can set options(warn=2), run the code, then do traceback(). Andy
> From: Simon.Bond > > Dear R-help, > > Can anyone explain the meaning of the warning, > > Singular precision matrix in level -1, block 1 > > ? Or how to track down where it comes from? > > More precisely, using the nlme package, I'm issued with the warning > > itt2 <- lme(lrna~rx.nrti+lbrna, random=~1|patid, > cor=corExp(form=~days|patid,nugget=T), weights=varPower( > form=~lbrna),data=rna3) > Warning messages: > 1: Singular precision matrix in level -1, block 1 > 2: Singular precision matrix in level -1, block 1 > > the output is: > > Linear mixed-effects model fit by REML > Data: rna3 > Log-restricted-likelihood: -4990.142 > Fixed: lrna ~ rx.nrti + lbrna > (Intercept) rx.nrtiZDV+3TC rx.nrtiZDV+ABC lbrna > 2.6597552 0.8589514 0.4259504 0.2929222 > > Random effects: > Formula: ~1 | patid > (Intercept) Residual > StdDev: 1.251113 0.2105329 > > Correlation Structure: Exponential spatial correlation > Formula: ~days | patid > Parameter estimate(s): > range nugget > 204.6422150 0.3349336 > Variance function: > Structure: Power of variance covariate > Formula: ~lbrna > Parameter estimates: > power > 0.9733358 > Number of Observations: 2390 > Number of Groups: 124 > > > > Thanks, > > Simon Bond. > > ______________________________________________ > [EMAIL PROTECTED] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html > > ______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
