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how to replace my double for loop which is little efficient!

bbslover 
Dear all,

My double for loop as follows, but it is little efficient, I hope all
friends can give me a "vectorized" program to replace my code. thanks

x: is a matrix  202*263,  that is 202 samples, and 263 independent variables

num.compd<-nrow(x); # number of compounds
diss.all<-0
for( i in 1:num.compd)
   for (j in 1:num.compd)
      if (i!=j) {
        S1<-sum(x[i,]*x[j,])
        S2<-sum(x[i,]^2)
        S3<-sum(x[j,]^2)
        sim2<-S1/(S2+S3-S1)
        diss2<-1-sim2
        diss.all<-diss.all+diss2}

it will cost a long time to finish this computation! i really need "rapid"
code to replace my code.

thanks

kevin

Thread (9 messages)

bbslover how to replace my double for loop which is little efficient! Dec 26 Berend Hasselman how to replace my double for loop which is little efficient! Dec 26 Dennis Murphy how to replace my double for loop which is little efficient! Dec 26 bbslover how to replace my double for loop which is little efficient! Dec 26 bbslover how to replace my double for loop which is little efficient! Dec 26 Berend Hasselman how to replace my double for loop which is little efficient! Dec 26 Berend Hasselman how to replace my double for loop which is little efficient! Dec 27 Berend Hasselman how to replace my double for loop which is little efficient! Dec 27 bbslover how to replace my double for loop which is little efficient! Dec 27