[Rd] names in optim()

Christophe Dutang dutangc at gmail.com
Fri Aug 21 13:52:37 CEST 2015

Dear both,

I have just found that names are treated in the same way in optim() depending on the optimization method. The example below shows the difference between the Brent method and the L-BFGS-B method.

f <- function(x){ y <- x^2;names(y) <-"f(x)";y}
optim(10, f, method="Brent", lower=-1, upper=10)$value
optim(10, f, method="L-BFGS-B", lower=-1, upper=10)$value

z <- 10
names(z) <- "x"
optim(z, f, method="Brent", lower=-1, upper=10)$par
optim(z, f, method="L-BFGS-B", lower=-1, upper=10)$par

Do you obtain the same behavior? 

I’m using R version 3.2.1 (2015-06-18)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: OS X 10.9.5 (Mavericks)

[1] fr_FR.UTF-8/fr_FR.UTF-8/fr_FR.UTF-8/C/fr_FR.UTF-8/fr_FR.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

loaded via a namespace (and not attached):
[1] tools_3.2.1 

Kind regards, CD
Christophe Dutang
LMM, UdM, Le Mans, France
web: http://dutangc.free.fr

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