Hi! I´m need a function that solves the equation f(x) = 0 (i.e. the root of the function) when f is a nonlinear function. Is there any? I´ve tried nlm and optim on the square of the function but the solution is very unstable. Thanks before hand. / Fredrik Thuring ------------------------------------------------------------------------------ This e-mail and any attachment may be confidential and may also be privileged. If you are not the intended recipient, please notify us immediately and then delete this e-mail and any attachment without retaining copies or disclosing the contents thereof to any other person. Thank you. ------------------------------------------------------------------------------ [[alternative HTML version deleted]]
On Wed, 8 Jun 2005 17:08:35 +0200 Fredrik Thuring wrote:> > Hi! > > I??m need a function that solves the equation f(x) = 0 (i.e. the root > of the function) when f is a nonlinear function. Is there any? I??ve > tried nlm and optim on the square of the function but the solution is > very unstable.Look at ?uniroot hth, Z> Thanks before hand. > > / Fredrik Thuring > > > --------------------------------------------------------------------- > --------- This e-mail and any attachment may be confidential and may > also be privileged. If you are not the intended recipient, please > notify us immediately and then delete this e-mail and any attachment > without retaining copies or disclosing the contents thereof to any > other person. Thank you. > --------------------------------------------------------------------- > --------- > [[alternative HTML version deleted]] > > ______________________________________________ > R-help at 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 >
On Wed, 2005-06-08 at 17:08 +0200, Fredrik Thuring wrote:> Hi! > > Im need a function that solves the equation f(x) = 0 (i.e. the root of > the function) when f is a nonlinear function. Is there any? Ive tried nlm > and optim on the square of the function but the solution is very unstable.Your colleague Martin Englund asked the same question. If x is scalar, you can use uniroot(). If it's a polynomial then polyroot() finds all the zeros. I hope that helps. Martyn