I think the problem with nls() is the model specification. Look: > y <- c(0.4334,0.3200,0.5848,0.6214,0.3890,0.5233,0.4753, + 0.2104,0.3240,0.2827,0.3847,0.5571,0.5432,0.1326,0.3481) > x <- c(0.3521,0.4334,0.3200,0.5848,0.6214,0.3890,0.5233, + 0.1379,0.2104,0.3240,0.3404,0.3847,0.5571,0.5432,0.1326) > dummy <- rep(c("m1","m2","m3"), c(7,3,5)) > > d <- data.frame(y=y, x=x, dummy=dummy) > > n0 <- nls(y~b0[dummy]+b1*x, data=d, + start=list(b0=c(1,1,1), b1=1)) > summary(n0)
Formula: y ~ b0[dummy] + b1 * x Parameters: Estimate Std. Error t value Pr(>|t|) b01 0.48616 0.13993 3.474 0.00520 ** b02 0.27626 0.09970 2.771 0.01820 * b03 0.39994 0.12597 3.175 0.00884 ** b1 -0.01735 0.28352 -0.061 0.95230 --- Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 Residual standard error: 0.1331 on 11 degrees of freedom Number of iterations to convergence: 1 Achieved convergence tolerance: 2.713e-07 I don't know abou nls2(). Walmes. ----- ..ooo0 ................................................................................................... ..(....)... 0ooo... Walmes Zeviani ...\..(.....(.....)... Master in Statistics and Agricultural Experimentation ....\_)..... )../.... walmeszevi...@hotmail.com, Lavras - MG, Brasil ............ (_/............................................................................................ -- View this message in context: http://r.789695.n4.nabble.com/nls-and-nls2-behavior-tp2173931p2173978.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.