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 <[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) ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
