Sundar, Have a look at "knn1" from package "class".
As I understand what you want is as.integer( knn1(train=A, test=B, cl=1:nrow(A)) ) Best regards Jens Oehlschlägel > Say I have a matrix A with dimension m x 2 and matrix B with > dimension n x 2. I would like to find the row in A that is closest to > the each row in B. Here's an example (using a loop): > set.seed(1) > A <- matrix(runif(12), 6, 2) # 6 x 2 > B <- matrix(runif(6), 3, 2) # 3 x 2 > m <- vector("numeric", nrow(B)) > for(j in 1:nrow(B)) { > d <- (A[, 1] - B[j, 1])^2 + (A[, 2] - B[j, 2])^2 > m[j] <- which.min(d) > } > All I need is m[]. I would like to accomplish this without using the > loop if possible, since for my real data n > 140K and m > 1K. I hope > this makes sense. -- ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html