maybe prob[cbind(1:length(y), y)]
I hope it helps. Best, Dimitris ---- Dimitris Rizopoulos Ph.D. Student Biostatistical Centre School of Public Health Catholic University of Leuven Address: Kapucijnenvoer 35, Leuven, Belgium Tel: +32/(0)16/336899 Fax: +32/(0)16/337015 Web: http://med.kuleuven.be/biostat/ http://www.student.kuleuven.be/~m0390867/dimitris.htm ----- Original Message ----- From: "Ingmar Visser" <[EMAIL PROTECTED]> To: <R-help@stat.math.ethz.ch> Sent: Friday, January 05, 2007 11:41 AM Subject: [R] Efficient multinom probs > Dear R-helpers, > > I need to compute probabilties of multinomial observations, eg by > doing the > following: > > y=sample(1:3,15,1) > prob=matrix(runif(45),15) > prob=prob/rowSums(prob) > diag(prob[,y]) > > However, my question is whether this is the most efficient way to do > this. > In the call prob[,y] a whole matrix is computed which seems a bit of > a > waste. > > Is there maybe a vectorized version of dmultinom which does this? > > Best, Ingmar > > ______________________________________________ > R-help@stat.math.ethz.ch 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. > Disclaimer: http://www.kuleuven.be/cwis/email_disclaimer.htm ______________________________________________ R-help@stat.math.ethz.ch 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.
