Message-ID: <1263864765734-1017196.post@n4.nabble.com>
Date: 2010-01-19T01:32:45Z
From: cjmr
Subject: Odp: For loops in R
In-Reply-To: <OF220C19DA.88C0ED29-ONC12576AF.003BEE73-C12576AF.003D536C@precheza.cz>
Hello Petr.
For the random values, I wanted to generate a different random number for
each element of my velocity matrix.
So will this do it?
rmat <- matrix(runif(1000), 500,2)
rmat2 <- matrix(runif(1000), 500,2)
rindex <- sample(1:500, replace=TRUE) #with repetition
velocity<-0.4 * velocity + rmat * (pbestsVar - popVar) + rmat2 *
(archiveVar[rindex,] - popVar)
Also, do the apply methods perform better than for loops given the same
function?
sample:
apply(x, fun)
and
for (i in 1:length(x)) fun(x[i])
cheers
cjmr
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