R does not really have a dedicated solver for nonlinear systems of equations, but instead you can use optim(), which is a minimizer. Suppose your system is F(x) = 0, where x \in R^p and F is a mapping from R^p to R^p, then you minimize the norm of F. The problem with this approach is that it can sometimes yield local minima which are not the zeros of the original system. However, this can be easily remedied by using different starting values.
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: [EMAIL PROTECTED] Webpage: http://www.jhsph.edu/agingandhealth/People/Faculty/Varadhan.html ---------------------------------------------------------------------------- -------- -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bill Shipley Sent: Wednesday, June 20, 2007 1:37 PM To: r-help@stat.math.ethz.ch Subject: [R] finding roots of multivariate equation Hello, I want to find the roots of an equation in two variables. I am aware of the uniroot function, which can do this for a function with a single variable (as I understand it...) but cannot find a function that does this for an equation with more than one variable. I am looking for something implementing similar to a Newton-Raphson algorithm. Thanks. -- Bill Shipley North American Editor for Annals of Botany Subject Editor for Ecology Département de biologie Université de Sherbrooke Sherbrooke (Québec) J1K 2R9 Canada ______________________________________________ R-help@stat.math.ethz.ch 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@stat.math.ethz.ch 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.
