# [R] Fwd: will vectorization help in this case?

Nachiketa Sahoo nsahoo at gmail.com
Mon Jan 23 07:57:12 CET 2006

```Hi all,

The previous post had some html formatting and did not go through. So,
here it is again in plain text.

I am doing a array marginalization over one dimension in the following manner:
===========================================================
for(l in 1:L)
{
flst=list(Pzu, Pzi, array(Puzu[,as.character(r[[l,"u"]])],
dim=dim(Puzu)[1], dimnames=dimnames(Puzu)[1]),
array(Pizi[,as.character(r[[l, "i"]])], dim=dim(Pizi)[1],
dimnames=dimnames(Pizi)[1]) );
tempa = 1;
for(j in 1:length(flst)) tempa = tempa %X% flst[[j]];

tempPzu = apply(tempa, 1, sum);
tPzu = tPzu + tempPzu;
tPuzu[,as.character(r[[l,"u"]])] = tPuzu[,as.character
(r[[l,"u"]])] + tempPzu;

tempPzi = apply(tempa, 2, sum);
tPzi = tPzi + tempPzi;
tPizi[,as.character(r[[l,"i"]])] =
tPizi[,as.character(r[[l,"i"]])] + tempPzi;

for(j in 1:ncomp) tPrjzuzilst[[j]][,,r[[l,rbase+j]]] =
tPrjzuzilst[[j]][,,r[[l,rbase+j]]] + tempa;
}
===========================================================
My question involves the operation using  tempPzu and tempPzi. Is my
use of loop in this case to addup certain arrays together, too ..
dumb? Is there another way of doing such things by vectorization?