perhaps this?

M <- dim(data_m)[2]

for(j in 1:M){
    for (i in 4:T) {
        data_q[i-3,j]=sum(data_m[(i-3):i,j])
    }
}

of course, you can vectorize this and speed it up significantly, but
there is something evil about premature optimization.

On Mar 2, 1:29 pm, Mohammad Sabr <mohammad_s...@yahoo.com> wrote:
> I am trying to run a loop where I can sum parts of a matrix. For example, I 
> want at each step in the loop to sum the the next 4-values of a vector. I 
> tried to do the following but the result were wrong:
>  
> for (i in 4:T) {
> data_q[i-3,]=sum(data_m[i-3,]:data_m[i,])}
>
>  
> can anyone please direct me on what should I do to run this loop properly
>  
> Thanks in advance
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> r-h...@r-project.org mailing listhttps://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guidehttp://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.

______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.

Reply via email to