Re: [R] newtons method

2009-05-14 Thread Hans W. Borchers
Dear Ravi: Thanks for pointing out the homotopy methods. Coming from Mathematics I was always considering SINGULAR for such a task which is also providing results when the solution set is not isolated points, but an algebraic variety. For single points, homotopy methods appear to be an

[R] newtons method

2009-05-12 Thread Kon Knafelman
Hi, Does anyone know how to code newton's method for finding the roots of polynomial functions? im not sure whether i need to do this manually, or just code something with a loop to stop when it gets to the desired result thanks guys!

Re: [R] newtons method

2009-05-12 Thread Uwe Ligges
Kon Knafelman wrote: Hi, Does anyone know how to code newton's method for finding the roots of polynomial functions? im not sure whether i need to do this manually, or just code something with a loop to stop when it gets to the desired result See ?optim for optimization methods. Uwe

Re: [R] newtons method

2009-05-12 Thread John C Nash
not be aware that optim() is contra-recommended for functions of 1 variable, which seems to be the problem here. But there is ?polyroot JN Message: 130 Date: Tue, 12 May 2009 11:12:51 +0200 From: Uwe Ligges lig...@statistik.tu-dortmund.de Subject: Re: [R] newtons method To: Kon Knafelman konk2

Re: [R] newtons method

2009-05-12 Thread Uwe Ligges
...@statistik.tu-dortmund.de Subject: Re: [R] newtons method To: Kon Knafelman konk2...@hotmail.com Cc: r-h...@stat.math.ethz.ch Message-ID: 4a093d93.1020...@statistik.tu-dortmund.de Content-Type: text/plain; charset=ISO-8859-1; format=flowed Kon Knafelman wrote: Hi, Does anyone know how

Re: [R] newtons method

2009-05-12 Thread Ravi Varadhan
: Tuesday, May 12, 2009 9:23 AM To: John C Nash Cc: r-help@r-project.org Subject: Re: [R] newtons method John C Nash wrote: Finding polynomial roots is not a problem where one wants a quick and dirty code. There are a lot of pitfalls, especially if there are roots that are multiples