With package nlmrt, I get a solution, but the Jacobian is essentially singular, so the model may not be appropriate. You'll need to read the documentation to learn how to interpret the Jacobian singular values. Or Chapter 6 of my book "Nonlinear parameter optimization with R tools."
Here's the script. Note nlxb is a little different from nls() and requires a data frame for the data. library(stats) x=c(30:110) y=c(0.000760289, 0.000800320, 0.000830345, 0.000840353, 0.000860370, 0.000910414, 0.000990490, 0.001090594, 0.001200721, 0.001350912, 0.001531172, 0.001751533, 0.001961923, 0.002192402, 0.002463031, 0.002793899, 0.003185067, 0.003636604, 0.004148594, 0.004721127, 0.005394524, 0.006168989, 0.007014544, 0.007870894, 0.008758242, 0.009656474, 0.010565620, 0.011485709, 0.012396520, 0.013308162, 0.014271353, 0.015326859, 0.016525802, 0.017889059, 0.019447890, 0.021223636, 0.023145810, 0.025174229, 0.027391752, 0.029645106, 0.032337259, 0.035347424, 0.039375125, 0.043575783, 0.048003973, 0.052926206, 0.058307309, 0.064581189, 0.071947231, 0.080494476, 0.089891885, 0.100671526, 0.111971207, 0.124237571, 0.137975539, 0.153629149, 0.171239194, 0.190712664, 0.212079979, 0.235026373, 0.259457493, 0.282867017, 0.307830359, 0.334773680, 0.364001719, 0.395742526, 0.425596389, 0.458391314, 0.494558651, 0.534657357, 0.579354317, 0.616075034, 0.656680256, 0.701804548, 0.752133146, 0.808558032, 0.872226001, 0.944664487, 1.027837007, 1.124484096, 1.238426232) vdata<- data.frame(x=x, y=y) a=0.0189 b=0.14328 delta=0.0005 # fit = nls(y ~ a*(exp(b*(x+0.5)))*((delta*b)/((delta*b)+(a*(exp(b*(x+0.5))-1))))^(0.5), # start=list(a=a,b=b, delta=delta), trace=TRUE) # predict(fit) # plot(x,y,col="red", xlab="Usia",ylab=expression(paste(mu))) # lines(x,predict(fit), col="blue") # legend("topleft", # c(expression(paste(mu)),"Fit"),col=c("red","blue"),lty=1:1) library(nlmrt) vformula <- y ~ a*(exp(b*(x+0.5)))*((delta*b)/((delta*b)+a*(exp(b*(x+0.5))-1)))^(0.5) fitjn = nlxb(formula= vformula, start=list(a=a,b=b,delta=delta), trace=TRUE, data=vdata) fitjn Best, JN On 15-08-12 06:37 AM, vidya wrote: > I get this error > Error in numericDeriv(form[[3L]], names(ind), env) : > Missing value or an infinity produced when evaluating the model > I was replace the starting value but still get error. > > Here is my code: > library(stats) > x=c(30:110) > y=c(0.000760289, 0.000800320, 0.000830345, 0.000840353, 0.000860370, > 0.000910414, 0.000990490, 0.001090594, 0.001200721, 0.001350912, > 0.001531172, 0.001751533, 0.001961923, 0.002192402, 0.002463031, > 0.002793899, 0.003185067, 0.003636604, 0.004148594, 0.004721127, > 0.005394524, 0.006168989, 0.007014544, 0.007870894, 0.008758242, > 0.009656474, 0.010565620, 0.011485709, 0.012396520, 0.013308162, > 0.014271353, 0.015326859, 0.016525802, 0.017889059, 0.019447890, > 0.021223636, 0.023145810, 0.025174229, 0.027391752, 0.029645106, > 0.032337259, 0.035347424, 0.039375125, 0.043575783, 0.048003973, > 0.052926206, 0.058307309, 0.064581189, 0.071947231, 0.080494476, > 0.089891885, 0.100671526, 0.111971207, 0.124237571, 0.137975539, > 0.153629149, 0.171239194, 0.190712664, 0.212079979, 0.235026373, > 0.259457493, 0.282867017, 0.307830359, 0.334773680, 0.364001719, > 0.395742526, 0.425596389, 0.458391314, 0.494558651, 0.534657357, > 0.579354317, 0.616075034, 0.656680256, 0.701804548, 0.752133146, > 0.808558032, 0.872226001, 0.944664487, 1.027837007, 1.124484096, > 1.238426232) > > a=0.0189 > b=0.14328 > delta=0.0005 > > fit = nls(y ~ > a*(exp(b*(x+0.5)))*((delta*b)/((delta*b)+(a*(exp(b*(x+0.5))-1))))^(0.5), > start=list(a=a,b=b, delta=delta)) > predict(fit) > plot(x,y,col="red", xlab="Usia",ylab=expression(paste(mu))) > lines(x,predict(fit), col="blue") > legend("topleft", > c(expression(paste(mu)),"Fit"),col=c("red","blue"),lty=1:1) > > > I really appreciate for the helps. Thank you. > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/nls-in-r-tp4711012.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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. > ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see 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.