solving equations with several variables
I tried:
f<-function(b,x)-sum(cos(x1+2.33474-2*(atan(b[1]*x2+b[2]*x3)))) optim(c(0, 0), f, x1=x1, x2=x2, x3=x3)
and got this error. Error in fn(par, ...) : unused argument(s) (x1 ...) I am trying to solve for the circular-linear regression equation in Fisher (1993).
===== Original Message From Uwe Ligges <ligges at statistik.uni-dortmund.de>
=====
Josh Schmidt wrote:
I am relatively new to R, but I would like to use it find the values of b1
and
b2 that maximize the following equation: (sum(cos(x3+2.33474-2(atan(b1*x1+b2*x2))))) Any help would be greatly appreciated.
Given b1 and b2 are scalars (we are minimizing f, hence maximizing -f): f <- function(b, x) -sum(cos(x3 + 2.33474 - 2*(atan(b[1]*x1 + b[2]*x2)))) optim(c(0, 0), f, x1=x1, x2=x2, x3=x3) Be careful: Do you know the solution is (a) unique and (b) without many local extrema? The function cos() is extremly dangerous for optimization!!! If you REALLY need it *and* you know optimization makes sense, you might want to give method "SANN" a try ... Uwe Ligges
Josh Schmidt Department of Biology and Wildlife University of Alaska Fairbanks 474-7006 (office)