Greetings, I am trying to fit a zero-inflated Poisson model using zeroinfl() from the pscl library. I have 5 covariates (4 continuous, 1 categorical); the categorical variable has 7 levels. I have had success fitting models that contain only the continuous covariates; however, when I add the categorical variable to any of the models (or if I run it by itself) I get the following error:
Error in solve.default(as.matrix(fit$hessian)) : system is computationally singular: reciprocal condition number = 3.46934e-20 The code I am using is: library(pscl) f1 <- formula(LOCS ~ as.factor(LCOVER) + D_ROADS + D_WATER + D_EDGE + D_GRASS) ZIP1 <- zeroinfl(f1, dist="poisson", link = "logit", data = FAWNS) There is no correlation between my covariates. Also, I tried reducing my categorical covariate to 3 levels and still receive the same error. Can anyone suggest why I may be getting this error when I add the categorical covariate? I appreciate your time and input. Thank you, Nate Nathan Svoboda Graduate Research Assistant Carnivore Ecology Lab Mississippi State University -- View this message in context: http://r.789695.n4.nabble.com/R-Error-System-is-computationally-singular-tp4631242.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
