Partial sum of a vector
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... at 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
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