[R] Avoiding for loops

[Berend Hasselman]

> On 25 Oct 2015, at 11:42, Maram SAlem <marammagdysalem at gmail.com> wrote:
> 
> Hi All,
> 
> I wonder if I can avoid the for() loop in any of the following loops.These
> loops are a part of a larger code which I'm trying to accelerate.
> 
> n=6
> m=4
> x<-c(0,1,1)
> 
> 1st loop
> 
> for (i in 1:m-1)
>   {
>   d[i]<- n- (sum(x[(1):(i)])) - i
>   }
>  e<- n*(prod(d))
> 
> 
On the basis of the other loops I presume you mean

for( in in 1:(m-1))

in stead of what you wrote.

You get the same result with 

d <- n - cumsum(x) - (1:(m-1))


Berend


>  2nd loop
> 
> LD<-list()
>   for (i in 1:(m-1))
>   {
>   LD[[i]]<-seq(0,x[i],1)
>   }
> 
>   LD[[m]]<-seq(0,(n-m-sum(x)),1)
>   LED<-expand.grid (LD)
>   LED<-as.matrix(LED)
> 
> 
> 3rd loop
> 
> for (i in 1:(m-1))
> 
>   {
> 
>    h[i]<- choose(x[i],LED[j,i])
> 
>     }
> 
> 
> 
> 4th loop
> 
> 
> for (i in 1:(m-1))
> 
>  {
> 
>    lm[i]<-(sum(LED[j,1:i])) + i
> 
>      }
> 
> 
> I appreciate if anyone has any suggestions or references.
> 
> 
> Thanks in advance.
> 
> 
> Maram Salem
> 
> 	[[alternative HTML version deleted]]
> 
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