# [R] Optimization problem, to minimize the length(rle(B)\$lengths) for all the rows and columns

From: Ng Stanley <stanleyngkl_at_gmail.com>
Date: Mon, 12 May 2008 21:13:53 +0800

Hi,

how can I order the rows and columns of a matrix A to generate B, in order to minimize the length(rle(B)\$lengths) for all the rows and columns ?

```> set.seed(5)
> a <- matrix(rnorm(200), nrow=20)
> a[a<=0] <- 0
> a[a>0] <- 1
> a
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10]
[1,]    0    1    1    0    1    0    1    0    0     1
[2,]    1    1    0    1    0    1    1    0    1     0
[3,]    0    1    0    0    1    1    0    1    1     1
[4,]    1    1    1    1    0    1    0    1    1     1
[5,]    1    1    0    0    1    0    1    0    0     0
[6,]    0    0    1    0    0    1    1    0    0     0
[7,]    0    1    0    0    1    0    0    1    0     0
[8,]    0    1    0    0    0    0    1    0    0     0
[9,]    0    0    0    0    0    0    0    0    0     1

[10,]    1    0    0    0    0    1    0    0    0     0
[11,]    1    1    1    0    1    0    1    1    0     1
[12,]    0    1    1    0    0    1    0    1    1     1
[13,]    0    1    1    1    1    1    0    0    0     0
[14,]    0    1    0    1    1    1    0    1    0     1
[15,]    0    1    0    1    1    0    1    0    0     0
[16,]    0    1    0    0    1    1    1    1    1     1
[17,]    0    0    1    1    0    0    1    0    1     1
[18,]    0    0    0    1    0    1    0    1    0     1
[19,]    1    0    0    1    0    1    1    0    1     0

[20,]    0    0    1    0    0    0    1    1    0     1

[[alternative HTML version deleted]]

______________________________________________
```
R-help_at_r-project.org 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. Received on Mon 12 May 2008 - 13:16:25 GMT

Archive maintained by Robert King, hosted by the discipline of statistics at the University of Newcastle, Australia.
Archive generated by hypermail 2.2.0, at Mon 12 May 2008 - 13:30:38 GMT.

Mailing list information is available at https://stat.ethz.ch/mailman/listinfo/r-help. Please read the posting guide before posting to the list.