[R] Loops question

[Uwe Ligges]

Ramzi Feghali wrote:

> 
> Hello Mr Ripley,

Whom is this mail adressed to? The mailing list R-help or Professor Ripley?


> i was waiting you to ask and if you don't mind if there is a fast way in R to do these loops made with R and that takes a week because my matrix is with thousand of rows.
> I got another method that is more fast and is utilised by many packages : interfacing with other languages", but it is only a question for information 
>  

So you are going to optimize the following code?


> foo<-function()
>  {for (i in 1:(n-1)){
>    for (k in (i+1):n){ 
>    b_0
>    for (j in 1:m){
>     if(bin[i,j]==TRUE&bin[k,j]==TRUE) b_b+1}
>          print (b)
>  } 
>      }
>   }
> 
> Thanks a lot
> Ramzi

There seems to be a logical n x m matrix called bin.
And the sollution of your problem should be solved within seconds by

  bin %*% t(bin)

where the upper triangular matrix of the result consists of the results 
for all i and k in your loops.

Uwe Ligges