similar to: how to get such a subset of a matrix?

Displaying 20 results from an estimated 20000 matches similar to: "how to get such a subset of a matrix?"

2006 Aug 07
2
Is there a function in R can help me to plot such a figure?
Hi, i want to plot figure like this, http://www.cis.hut.fi/projects/somtoolbox/download/pics2/shotvs2_colorcode.png So is there a function or package in R can help me to do this. Any suggestion will be appreciated. Thanks in advance Jiantao Shi [[alternative HTML version deleted]]
2005 Feb 07
4
proportional matrix rows
Hi I have a two-column integer matrix like this: R> jj [,1] [,2] [1,] -1 1 [2,] -2 2 [3,] -7 6 [4,] -8 7 [5,] -6 5 [6,] -9 8 [7,] -5 4 [8,] 3 -3 [9,] -10 9 [10,] -4 3 I want a diagnostic that detects whether a row is a multiple of the first row or not. In this case, this would be rows 1,2, and 8. How to do this
2006 Nov 17
2
do.call("+", ...)
Hi How do I make do.call() take "+" as a function for a list of more than two elements? Toy problem follows: f <- function(i){matrix((1:6)^i,2,3)} # Thus f() returns a matrix of size 2x3; I want to add a whole bunch of such matrices, # as in f(1) + f(2) + f(3) + f(4) # But: > do.call("+",sapply(1:4,f,simplify=FALSE)) Error in do.call("+",
2005 Oct 09
2
How to get the remaining vector after sampling a subset?
Hi , I have a vector,for example, x=rnorm(100) Then i rendom choose 20 of them. chosen=sample(x,20). And i want to get the remain values in x. Is there a quick way to go? Thanks in advance. [[alternative HTML version deleted]]
2005 May 11
3
How to plot a matrix with 18 rows by row vs. a vector in a single graph, resulting 18 lines with different colors?
I have a matrix gene=array(rnorm(180), dim=c(18,10)) and a vector time=c(0, 0.5,2,4,6,8,12,24,48,72). So i can get a plot with plot(time,gene[1,],type="b",col="green") for the first row.So how can i get all the 18 rows in the same plot VS. the same vector time=c(0,0.5,2,4,6,8,12,24,48,72). Any suggestions.Thanks ! [[alternative HTML version deleted]]
2006 Feb 14
3
Inf values in a matrix
Hello, I have some Inf values in a matrix, but I don't want to replace them with some value but rather remove the rows that contain the Inf values. Also I would like to record the rows which were removed. Is there an easy way to do this instead of writing loops over the matrix? Thanks. Ita Cirovic Donev
2010 Dec 02
1
Arrange elements on a matrix according to rowSums + short 'apply' Q
Greetings, My goal is to create a Markov transition matrix (probability of moving from one state to another) with the 'highest traffic' portion of the matrix occupying the top-left section. Consider the following sample: inputData <- c( c(5, 3, 1, 6, 7), c(9, 7, 3, 10, 11), c(1, 2, 3, 4, 5), c(2, 4, 6, 8, 10), c(9, 5, 2, 1, 1) ) MAT <- matrix(inputData,
2011 Nov 29
1
Sum matrix by rows, conditional on value
I'd like to sum a matrix only where the matrix meets a specific condition. The matrix has 365 rows and about 50,000 columns. str(cdem.mat.yr) num [1:365, 1:41772] -43.5 -48.4 -45.9 -38.4 -32 ... I'm having trouble replicating this because it is not working out for me, so I'm unsure I can provide an solid working example (apologies). I would like to subset my matrix where the values
2005 May 13
2
how to generate object name automatically?
Hi everybody, I have a lable vector , raw.labs= paste("file1", 1:20, sep = "") And i can i make the content of raw.labs to be a object name. eg ,file1=123(use some function on raw.labs to generate the name file1) Thanks! [[alternative HTML version deleted]]
2007 Dec 12
2
Matrix Inversion
I got the following error: a = read.csv("mat.csv") b = as.matrix(a) tb = t(b) bb = tb %*% b dim(bb) ibb = solve(bb) bb %*% ibb > ibb = solve(bb) Error in solve.default(bb) : system is computationally singular: reciprocal condition number = 1.77573e-19 > Are there any ways to find more information about why it is singular? Thanks.
2007 Apr 24
5
intersect more than two sets
Hi, I searched the archives and did not find a good solution to that. assume I have 10 sets and I want to have the common character elements of them. how could i do that? -- Weiwei Shi, Ph.D Research Scientist GeneGO, Inc. "Did you always know?" "No, I did not. But I believed..." ---Matrix III
2007 Feb 13
4
Generating MVN Data
Dear All I want to generate multivariate normal data in R for a given covariance matrix, i.e. my generated data must have the given covariance matrix. I know the rmvnorm command is to be used but may be I am failing to properly assign the covariance matrix. Any help will be greatly appreciated thanks. M. R. Ahmad
2010 Mar 05
2
Selecting rows of a matrix based on some condition on the columns
The data set consists of two sets of matrices, as labelled by the columns, T's and C's. > xy x T1 T2 T3 T4 T5 C1 C2 C3 C4 C5 [1,] 50 0.00 0.00 33.75 0.00 0.00 0.00 36.76 0.00 35.26 0.00 [2,] 13 34.41 0.00 0.00 36.64 32.86 34.11 35.80 37.74 0.00 0.00 [3,] 14 35.85 0.00 33.88 36.68 34.88 34.58 0.00 32.75 37.45 0.00 [4,] 33 34.56
2005 Mar 16
8
Summing up matrices in a list
Dear all, I think that my question is very simple but I failed to solve it. I have a list which elements are matrices like this: >mylist [[1]] [,1] [,2] [,3] [1,] 1 3 5 [2,] 2 4 6 [[2]] [,1] [,2] [,3] [1,] 7 9 11 [2,] 8 10 12 I'd like to create a matrix M<-mylist[[1]]+mylist[[2]] [,1] [,2] [,3] [1,] 8 12 16 [2,] 10 14 18
2007 Sep 07
2
confusion matrix - better code?
Hi, I’ve written some code to obtain a confusion matrix when the true classification and the predicted classification are known. Suppose true classification is called “tr” and predicted classification is “pr”. I have 4 classes in tr, but only 3 classes out of 4 are predicted in “pr”. Following is my code, but looks quite “clunky” to me. I wonder if you have any suggestions to improve it.
2005 Feb 09
4
subset
Dear all, I am trying to extract rows from a data.frame based on the rowSums != 0. I want to preserve rownames in the first column in the subset. Does anyone know how to extract all species that don't have rowSums equal to zero? Here it is: # dataset x <- data.frame( species=c("sp.1","sp.2","sp.3","sp.4"), site1=c(2,3,0,0), site2=c(0,0,0,0),
2007 May 20
2
Number of NA's in every second column
Hi R-users, How do I calculate a number of NA's in a row of every second column in my data frame? As a starting point: dfr <- data.frame(sapply(x, function(x) sample(0:x, 6, replace = TRUE))) dfr[dfr==0] <- NA So, I would like to count the number of NA in row one, two, three etc. of columns X1, X3, X5 etc. Thanks in advance Lauri [[alternative HTML version deleted]]
2012 Oct 05
3
loop for column substraction of a matrix
Dear useRs, I have a matrix with 38 columns and 365 rows. what i want to do is the following..... 1. subtracting from each column, first itself and then all the remaining columns. More precisely, from column number 1, i will first subtract itself(column 1) and then the remaining 37 columns. Afterwards i will take column number 2 and do the same. In this way i want to proceed till 38th column.
2006 Oct 16
5
Re : Generate a random bistochastic matrix
Thanks, I tried someting like this, but computation takes times for large matrices btransf <- function(y,X=length(y)^4) { N <- length(y) bm <- matrix(rep(1/N,N^2),N,N) for(j in 1:X){ coord <- sample(1:N,4,replace=T) d <- runif(1,0,min(bm[coord[1],coord[2]],bm[coord[3],coord[4]]))
2005 Jan 05
4
output from table() in matrix form
Hi How do I get the output from table() in matrix form? If I have R> table(c(1,1,1,1,2,20)) 1 2 20 4 1 1 I want [,1] [,2] [,3] [1,] 1 2 20 [2,] 4 1 1 The problem is that names(table) is a vector of characters and I need the numeric values. I am using R> rbind(as.integer(names(x)),x) I thought tabulate() might be better as it takes an