Hi, I found at least 2 typos in your function. Can you check your equations carefully to make sure that they are correct and then send me a reproducible version of the code that I can cut and paste into my R session?
Ravi. ---------------------------------------------------------------------------- ------- Ravi Varadhan, Ph.D. Assistant Professor, The Center on Aging and Health Division of Geriatric Medicine and Gerontology Johns Hopkins University Ph: (410) 502-2619 Fax: (410) 614-9625 Email: rvarad...@jhmi.edu Webpage: http://www.jhsph.edu/agingandhealth/People/Faculty_personal_pages/Varadhan.h tml ---------------------------------------------------------------------------- -------- -----Original Message----- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of stenort Sent: Thursday, July 23, 2009 6:08 AM To: r-help@r-project.org Subject: [R] Non-negative solutions to complicated equations Hi all, I have a system of 3 equations with many defined parameters and 3 variables I need to find solutions to. I actually know the solutions I'm aiming for (0.07,0.287,0.0061) but R tends to give me (0,0,0). I tried the "BB" package but don't really follow how to refine my solutions from that; these are wrong so far. Here's my code from trying that: > f<-function(x){ + x1<-x[1] + x2<-x[2] + x3<-x[3] + + F<-rep(NA,3) + F[1]<-(0.075*x3+0,175*x2)*0.065*exp(-0.03*25) + F[2]<-(x2/0.075)*((1/50)/(0.065*0.5.125*0.872214*(1-(x2*(56/25))))-0.1 + 75) + F[3]<-(x3/0.175)*((1/70)/(0.065*0.366*0.872214*(1-(x3*(66/35))))-0.075 + ) + return(F) + } > p0<-c(0.1,0.1,0.1) > dfsane(par=p0,fn=f,control=list(maxit=3000)) I have substituted estimated values for all the parameters into the above equations. Thanks -- View this message in context: http://www.nabble.com/Non-negative-solutions-to-complicated-equations-tp2462 2867p24622867.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. ______________________________________________ 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.
