Hi Komal,
Try this:
walk2d<-function(n){
rw <- matrix(0, ncol = 2, nrow = n)
# generate the indices to set the deltas
indx <- cbind(seq(n), sample(c(1, 2), n, TRUE))
# now set the values
rw[indx] <- sample(c(-1, 1), n, TRUE)
# cumsum the columns
rw[,1] <- cumsum(rw[, 1])
rw[,2] <- cumsum(rw[, 2])
cbind(rw[,1],rw[,2]) # changed this
}
# example
n <- 100
rw <- walk2d(n)
plot(rw, xlab="x", ylab="y", main="Random Walk Simulation In Two
Dimensions",
xlim = range(rw[,1]), ylim = range(rw[,2]), las = 1)
HTH,
Jorge
On Wed, Jun 29, 2011 at 11:44 AM, Komal <> wrote:
>
>
>
> walk.2d<-function(n)
> {
> rw <- matrix(0, ncol = 2, nrow = n)
>
> # generate the indices to set the deltas
> indx <- cbind(seq(n), sample(c(1, 2), n, TRUE))
>
> # now set the values
> rw[indx] <- sample(c(-1, 1), n, TRUE)
>
> # cumsum the columns
> rw[,1] <- cumsum(rw[, 1])
> rw[,2] <- cumsum(rw[, 2])
>
> return(rw[,1],rw[,2])
>
> }
> n<-1000
>
> plot(walk.2d(n), type="n",xlab="x",ylab="y",main="Random Walk Simulation In
> Two Dimensions",xlim=range(rw[,1]),ylim=range(rw[,2]))
>
> # use 'segments' to color each path
> segments(head(rw[, 1], -1), head(rw[, 2], -1), tail(rw[, 1], -1), tail(rw[,
> 2], -1), col ="blue")
>
>
> This code is giving me error in the return()... what to write in
> return()???
> please help.
>
>
> --
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>
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