On Dec 6, 2010, at 15:15 , Jonathan P Daily wrote: > Correct me if I'm wrong, but isn't the minimal x value in your example the > same regardless of what positive coefficient you apply to x? If that is > the case, you would expect the same min(x) for each iteration. > > i.e. in the interval [0,1] the minimum x value of x^2 + x is the same as > x^2 + 100000000*x, at x = 0.
You're wrong --- slightly. The returned $minimum is the x, the y is $objective. But the interval given doesn't bracket the minimum, as you'll clearly see if you put int=c(-10,10). The only puzzling bit is that optimize() doesn't actually return the left endpoint, but rather the first evaluation point inside the interval. The rather wide tolerance of .Machine$double.eps^0.25 == 0.0001220703 probably plays a role in this. -- Peter Dalgaard Center for Statistics, Copenhagen Business School Solbjerg Plads 3, 2000 Frederiksberg, Denmark Phone: (+45)38153501 Email: pd....@cbs.dk Priv: pda...@gmail.com ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
