[R] ^ operation much slower in R 1.7.1 than in R 1.7.0 ???

[Philippe Grosjean]

I do not understand what happens here (under Win XP):

a <- abs(matrix(rnorm(800*800)/2, ncol=800, nrow=800))
system.time(b <- a^1000)[3]

took about 1 sec on my computer with R 1.7.0 and it takes now 4.59 sec with
R 1.7.1

Similarly,

phi <- 1.6180339887498949
a <- floor(runif(750000)*1000)
system.time(b <- (phi^a - (-phi)^(-a))/sqrt(5))[3]

took about 0.9 sec with R 1.7.0, and it takes 11.8 sec (!!!) in R 1.7.1.

Are there some changes made between 1.7.0 and 1.7.1 that could cause such a
large difference in time to do such simple computations???

Best,

Philippe Grosjean


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