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)
Sorry, should have been:
f <- function(b, x1, x2, x3){
-sum(cos(x1+2.33474-2*(atan(b[1]*x2+b[2]*x3))))
}
optim(c(0, 0), f, x1=x1, x2=x2, x3=x3)Uwe Ligges
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 <[EMAIL PROTECTED]>
=====
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)
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