[R] How to remove double for loop?

[Gabor Grothendieck]

Try this:

V <- diag(n+1); i <- row(V) - 1; j <- col(V) - 1
(j > i) * u ^ i * d ^ (j - i)

On Wed, Mar 19, 2008 at 7:24 AM, Jonas Malmros <jonas.malmros at gmail.com> wrote:
> Hello everyone.
>
> I use double for loops to fill in matrices, but there are surely
> better (and computationally faster) ways to perform that task.
> Could someone show me, given the following example of a double for
> loop, how this could be done? It is much easier to learn by examples.
>
> Val <- matrix(0, nrow=n+1, ncol=n+1)
> for( i in 0:n){
>    for(j in 0:i){
>        Val[j+1, i+1] <- u^j*d^(i-j)
>    }
> }
>
> Thank you in advance!
>
> --
> Jonas Malmros
>
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