[R] Non-linear system of equations

Radka Pancheva radica at abv.bg
Sun Apr 27 09:10:22 CEST 2008


Hello,

Thank you all for your answers. I'll try them all and I'm sure it will work.


 >
 >Try this:
 >
 >> library(Ryacas)
 >> x <- Sym("x")
 >> y <- Sym("y")
 >> Solve(List(x^2+y^2==6, x-y==3), List(x,y))
 >expression(list(list(x == root(6 - y^2, 2), y == y)))
 >
 >
 >2008/4/25 Radka Pancheva <radica at abv.bg>:
 >> Hello R users,
 >>
 >> I am trying to estimate the parameters of a bimodal normal distribution using moments matching, so I have to solve a non-linear system of equations. How can I solve the following simple example?
 >>
 >> x^2 - y^2 = 6
 >> x – y = 3
 >>
 >> I heard about nlsystemfit, but I don't know how to run it exactly. I have tried the following code, but it doesn't really work:
 >>
 >>
 >> f1 <-y~ x[1]^2-x[2]^2-6
 >> f2 <-z~ x[1]-x[2]-3
 >> f  <- list(f1=0,f2=0)
 >> nlsystemfit("OLS",f,startvals=c(0,0))
 >>
 >> Thank You in advance for your help.
 >>
 >>
 >> ______________________________________________
 >> R-help at 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.
 >>
 >



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