search for: subdiagonal

I'm trying to enter a vector into the subdiagonal of a matrix but cannot find a command in R which corresponds to the MatLab version of diag(vec, k), where vec = the vector of interest, and k = the diagonal (k=0 for the diagonal; k=-1 for the subdiagonal; k=1 for superdiagonal, etc.) Is there an equivalent command in R? I'm looking fo...

I want to construct a symmetric band matrix in the Matrix package from a matrix where the first column contains data for the main diagonal, the second column has data for the first subdiagonal/superdiagonal and so on. Since the Matrix will be 10^5 x 10^5 or so, with perhaps 10-20 non-zero elements above the diagonal per row, I can't do it by constructing a full matrix and then using the band() function to subset it to a band matrix. Any suggestions? -thomas Thomas Lumley...

...als in a MATRIX and have been accustomed to using spdiags in MATLAB or Octave. I've got a solution pieced together using for loops and it works though isn't vectorized and liable to run very slow for large matrices. As an example: A = 1 2 3 4 5 9 8 7 6 5 4 5 6 7 8 5 4 3 2 1 8 7 6 0 1 The subdiagonals are: 9,5,3,0 4,4,6 5,7 and 8, I know about lower.tri and can fetch the data in a resulting vector which ,in this case, would be: 9,4,5,8,5,4,7,3,6,0 though I would have to manipulate this some more to extract the other diagonals (imagine this being done for say a 1000 x 1000 matrix). I look...

Hi Suppose I have a matrix (cohort are rows and years are columns) [2000] [2001] [2002] [2003] [C1] 0.01 0.03 0.02 0.09 [C2] 0.06 0.05 0.07 0.11 [C3] 0.1 0.5 0.4 0.98 [C4] 0.7 0.6 0.2 0.77 I want to extracts the diagonals to get a matrix which looks like this (C1 becomes C2 in 2002, C2 becomes C3 in 2003

Dear R-list, I am in the process of translating a long function written in Matlab into R (mainly because I am a big of fan of R, and folks will not have to pay to use it :). In the translation of this function I got stack because they use spdiags, which, as far as I can tell it is not available in R. I have explored the Matrix package, from which I borrowed some of the functions (e.g.,

Hi I want to write a little function that takes a vector of arbitrary length "n" and returns a matrix of size n+1 by n+1. I can't easily describe it, but the following function that works for n=3 should convey what I'm trying to do: f <- function(x){ matrix(c( 1 , 0 , 0 , 0, x[1] , 1 , 0 , 0, x[1]*x[2] , x[2] , 1 , 0,

...e: Sorting rows of a matrix independent of each other > (Paul Smith) > 73. Re: How to find maximum values on the density function of > arandom variable (guox@ucalgary.ca) > 74. Re: Sorting rows of a matrix independent of each other (Kevski) > 75. Re: Matrix Construction; Subdiagonal (Paul Smith) > 76. Re: search for string insider a string (Gabor Grothendieck) > 77. Re: How to find maximum values on the density function of > arandom variable (David Winsemius) > 78. Re: Unable to run smoother in qplot() or ggplot() - complains > about knots (Christop...