Hi,
AKS> But when I want to get [transpose(weight)][s][weight] using following AKS> syntax, AKS> t(weight)%*%s%*%weight I guess 'weight' and 's' are dataframes and you need matrices. Like here: x <- rnorm(8) s <- matrix(rnorm(64), ncol=8) t(x) %*% s %*% x # this is OK d <- as.data.frame(x) t(d) %*% s %*% d # this is your error You can use data.matrix() to convert dataframes to matrices: t( data.matrix(d) ) %*% s %*% data.matrix(d) # again OK HTH, Michal ~,~`~,~`~,~`~,~`~,~`~,~`~,~`~,~`~,~ Michal Bojanowski ICS/Utrecht Utrecht University Heidelberglaan 2; 3584 CS Utrecht Room 1428 [EMAIL PROTECTED] ______________________________________________ [email protected] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
