Re: [R] randomize a matrix
hi Cameron It so happens that the particular example P you chose has no partners under the symmetry you describe. Can you explain what this is to be used for? Could you also give an example of what the operation you desire might look like if it was successful, and show exactly what you mean by row and column sums? Does the order of row and column sums have to stay the same, ie: is 0 1 0 0 symmetric with 1 0 0 0 or not? -Alex Brown On 19 Oct 2006, at 20:49, Guenther, Cameron wrote: Hello everyone, If I have an incidence matrix of 0 and 1's P=[1 1 1 1 1 1 1 1 1 1 0 0 1 1 1 0 0 0 1 1 1 0 0 0 1 1 0 0 0 0] I want to create a new uniform random matrix [a] that is filled with 0's and 1's but constrained so that the row and column sums are the same as in [P]. Does anyone know how to accomplish this? Thanks in advance Cameron Guenther, Ph.D. Associate Research Scientist FWC/FWRI, Marine Fisheries Research 100 8th Avenue S.E. St. Petersburg, FL 33701 (727)896-8626 Ext. 4305 [EMAIL PROTECTED] __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting- guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] randomize a matrix
Cameron, In your example, I think P is the only matrix with 0-1 entries that has the given row and column sums. In general, I would solve the problem simulating a Markov Chain. Start from a given incidence matrix A and iterate the following steps: (1) select two rows, a, b, and two columns, i, j, at random. (2) If A[c(a,b), c(i,j)] is of one of the forms 1 0 or0 1 0 1 1 0 then set it to the other, i.e. set A[c(a,b), c(i,j)] - A[c(b,a), c(i,j)]. After sufficiently many iterations, A will have a uniform distribution. Giovanni Date: Thu, 19 Oct 2006 15:49:55 -0400 From: Guenther, Cameron [EMAIL PROTECTED] Sender: [EMAIL PROTECTED] Precedence: list Thread-topic: [R] randomize a matrix Thread-index: Acbzt8BjJUXZEHZgQNaMi9gYYuh3Sg== Hello everyone, If I have an incidence matrix of 0 and 1's P=[1 1 1 1 1 1 1 1 1 1 0 0 1 1 1 0 0 0 1 1 1 0 0 0 1 1 0 0 0 0] I want to create a new uniform random matrix [a] that is filled with 0's and 1's but constrained so that the row and column sums are the same as in [P]. Does anyone know how to accomplish this? Thanks in advance Cameron Guenther, Ph.D. Associate Research Scientist FWC/FWRI, Marine Fisheries Research 100 8th Avenue S.E. St. Petersburg, FL 33701 (727)896-8626 Ext. 4305 [EMAIL PROTECTED] __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. -- __ [ ] [ Giovanni Petris [EMAIL PROTECTED] ] [ Department of Mathematical Sciences ] [ University of Arkansas - Fayetteville, AR 72701 ] [ Ph: (479) 575-6324, 575-8630 (fax) ] [ http://definetti.uark.edu/~gpetris/ ] [__] __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] randomize a matrix
Hello everyone, If I have an incidence matrix of 0 and 1's P=[1 1 1 1 1 1 1 1 1 1 0 0 1 1 1 0 0 0 1 1 1 0 0 0 1 1 0 0 0 0] I want to create a new uniform random matrix [a] that is filled with 0's and 1's but constrained so that the row and column sums are the same as in [P]. Does anyone know how to accomplish this? Thanks in advance Cameron Guenther, Ph.D. Associate Research Scientist FWC/FWRI, Marine Fisheries Research 100 8th Avenue S.E. St. Petersburg, FL 33701 (727)896-8626 Ext. 4305 [EMAIL PROTECTED] __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.