similar to: Creating list from matrix

Hi, I have a correlation matrix of about 3000 items, i.e., a 3000*3000 matrix. For each of the 3000 items, I want to get the top 50 items that have the highest correlation with it (excluding itself) and generate a data frame with 3 columns like ("ID", "ID2", "cor"), where ID is those 3000 items each repeat 50 times, and ID2 is the top 50 correlated items with ID,

Hi Everybody, I have a matrix of about 45 columns. Some of the rows contain zeros. Using >data1<-data[complete.cases(data),], I can remove the "NA" rows. But I am unable to tackle that of zeros. Can anybody give me an idea of how to remove rows containing zeros in a matrix. Thanks so much Best Ogbos [[alternative HTML version deleted]]

useR's, I have a matrix given by the code: mat <- matrix(c(rep(NA,10),1,2,3,4,5,6,7,8,9,10,10,9,8,NA,6,5,4,NA,2,1,rep(NA,10),1,2,3,4,NA,6,7,8,9,10),10,5) This is a 10x5 matrix containing missing values. All columns except the second contain missing values. I want to delete all columns that contain ALL missing values, and in this case, it would be the first and fourth columns. Any column

Hi All. Imagine you have a large block diagonal matrix. I'd like to replace the zeros in this matrix with small random (runif) numbers. Any ideas for a simple and efficient way to do this? Best regards, Rick DeShon

Hi, I am looking for two ways to speed up my computations: 1. Is there a function that efficiently computes the 'sandwich product' of three matrices, say, ZPZ' 2. Is there a function that efficiently computes the determinant of a positive definite symmetric matrix? Thanks, S.A. [[alternative HTML version deleted]]

Hi r-help community, This question isn't so much a syntax/coding one, but here goes: Let's say I have matrix of arbitrary dimensions and I'd like to reorder the rows in such a way that I could maximize the sum of the entries along the diagonal. For example, for this 3x3 matrix: [,1] [,2] [,3] [1,] 3 4 13 [2,] 9 1 2 [3,] 2 11 1 rearranging the rows

I have a matrix that I want to turn into a transformed matrix that includes the indices from the original matrix and the value. The matrix is simply real-valued and is square (and large (8k x 8k)). I want something that looks like (for the 3x3 case): i j value 1 1 1.0 1 2 0.783432 1 3 -0.123482 2 1 0.783432 2 2 1.0 2 3 0.928374 and so on.... I can do this with for loops, but there is

Dear all, suppose I have following matrix:   > mat <- matrix(rnorm(25), 5) > > mat             [,1]       [,2]        [,3]       [,4]       [,5] [1,]  0.97056228 -1.3278509 -0.73511792  2.1650629 -0.4411997 [2,]  0.58613700 -0.2559899 -1.18334248 -1.4990907  1.8138846 [3,] -1.03333313  2.0227887  0.89622681  0.6483973 -1.5523283 [4,]  0.38968833  0.2490004 -0.02301061 -0.2705150

Hi all, Suppose we have the following matrix m <- matrix(c(1,2,3,2,1,3,3,1,2), ncol = 3, byrow=T) where in each row each number occurs only once. I'd like to define a permutation, e.g. 1 -> 2, 2 -> 1, 3 -> 3 and apply it to the matrix. Thus, the following matrix should result: m.perm <- matrix(c(2,1,3,1,2,3,3,2,1), ncol = 3, byrow=T) i.e. each 1 should map to 2 and vice

Hi all, If I have a huge matrix/ dataframe and I want to create a new matrix/ dataframe with every second (or third, or fourth etc.) row of the original matrix, how can I do it? Any help much appreciated. Thanks, Umesh [[alternative HTML version deleted]]

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I have a rectangular matrix of size 920 by 85. I'd like to coerce it into a square matrix such that all row/col names are present in the new matrix and the additional values are zero. As an example: A B C D A 1 2 3 4 E 5 6 7 8 F 9 10 11 12 Would be coerced to: A B C D E F A 1 2 3 4 5 9 B 2 0 0 0 6 10 C 3 0 0

Hi all, Given a matrix: > mat [,1] [,2] [,3] [1,] 0 0 0 [2,] 3 3 3 [3,] 1 1 1 [4,] 2 1 1 How can I convert it to a list of strings: > desired_output [1] "aaa" "ttt" "ccc" "gcc" In principle: 1. Number of Column in matrix = length of string (= 3) 2. Number of Row in matrix = length of vector ( = 4). 3.

Dear all I have data like this: x y [1,] 59.74889 3.1317081 [2,] 38.77629 1.7102589 [3,] NA 2.2312962 [4,] 32.35268 1.3889621 [5,] 74.01394 1.5361227 [6,] 34.82584 1.1665412 [7,] 42.72262 2.7870875 [8,] 70.54999 3.3917257 [9,] 59.37573 2.6763249 [10,] 68.87422 1.9697770 [11,] 19.00898 2.0584415 [12,] 60.27915 2.5365194 [13,] 50.76850

Hi, I have a matrix with m rows and n column and a vector with n elements. I want to divid each rows of the matrix by vector direcly. could you please hint me? Thank you khazaei

Dear all, I am trying to split a matrix into 2 as efficiently as possible. It is a character matrix: 1 2 3 1 "2-271" "2-367" "1-79" 2 "2-282" "2-378" "1-90" 3 "2-281" "2-377" "1-89" I want to make 2 matrices from this, as succinctly and efficiently as possible. I've tried such

Hi, I have a matrix that looks like this a <- c(1,1,1,1,2,2,3,3,3,3) b <- c(2,2,2,3,4,4,4,5,5,6) c <- c(1,2,3,4,5,6,7,8,9,10) M <- matrix(nr=10,nc=3) M[,1] <- a M[,2] <- b M[,3] <- c > M [,1] [,2] [,3] [1,] 1 2 1 [2,] 1 2 2 [3,] 1 2 3 [4,] 1 3 4 [5,] 2 4 5 [6,] 2 4 6 [7,] 3 4 7

Dear all, I've got many responses to my initial question, which is stated below. However, from those responses it has become clear that I need to rephrase my problem. All responses dealt with subscripting the data matrix before 'apply' is run on it. But this is not want I wanted to do. 'apply' cycles through rows or columns of a matrix, and runs a function on each row or

HI, I am really messing up to make a symmetrical matrix using upper.tri() & lower.tri() function. Here is my code:   > set.seed(1) > mat = matrix(rnorm(25), 5, 5) > mat            [,1]       [,2]       [,3]        [,4]        [,5] [1,] -0.6264538 -0.8204684  1.5117812 -0.04493361  0.91897737 [2,]  0.1836433  0.4874291  0.3898432 -0.01619026  0.78213630 [3,] -0.8356286  0.7383247

Hi all, I have a matrix, for example [,1] [,2] [1,] 1 3 [2,] 4 6 I want to replicate the matrix twice and add an extra column at the end, which is [,1] [,2] [,3] [,4] [,5] [,6] [,7] [1,] 1 3 1 3 1 3 2 [2,] 4 6 4 6 4 6 5 I found 'rep' only works for vector. Does anyone know how to replicate a matrix, and append the matrix?

Hi all, I have created following codes : mat = cbind(c(0.000059710430,0.000023057380), c(0.000023057380, 0.00005971089)) set.seed = 1000 vary = runif(dim(mat)[1], 2000, 3000) calc = function(mat, vary) { result = vector(length = (length(vary)+1)) result[1] = sqrt(t(vary) %*% vary) for (i in 1 : length(vary)) { result[(i+1)] = sum(vary)*sum(vary*mat[,i])