[R] dependent nested for loops in R
David Winsemius
dw|n@em|u@ @end|ng |rom comc@@t@net
Sun Jan 31 06:01:30 CET 2021
On 1/30/21 8:26 PM, Shaami wrote:
> Hi
> I have very large dependent nested for loops that are quite expensive
> computationally. It takes weeks and does not end to give me results. Could
> anyone please guide how could I use apply function or any other suggestion
> for such big and dependent loops in R? A sample code is as follows.
>
> w = NULL
> for(j in 1:1000)
> {
> x = rnorm(2000)
> z = x[1]
> for(i in 2:2000)
> {
> z = x[i]+5*z[i-1]
I'm guessing you meant to type:
z[i] <- x[i]+5*z[i-1]
> if(z>4 | z<1) {
And more guesses (in the absence of any sort of problem description)
that you really wanted:
if(z[i]>4 | z[i]<1) { ....
> w[j]=i
> break
> } else {
> w[j] = 0
> }
> }
> }
Are you sure you need a for-loop? Seems like you could have done this
with a couple of vectorized operations. And the `break` looked entirely
superfluous.
> Thank you
>
> [[alternative HTML version deleted]]
>
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