I would like to be able to randomise presence-absence (i.e. binary) matrices whilst keeping both the row and column totals constant. Is there a function in R that would allow me to do this?
I'm working with vegetation presence-absence matrices based on field observations. The matrices are formatted to have sites as rows and species as columns. The presence of a species on a site is indicated with a 1 (absence is obviously indicated with a 0). I would like to randomise the matrices many times in order to construct null models. However, I cannot identify a function in R to do this, and the programming looks tricky for someone of my limited skills. Can anybody help me out? Many thanks, Nick Cutler Institute of Geography School of Geosciences University of Edinburgh Drummond Street Edinburgh EH8 9XP United Kingdom Tel: 0131 650 2532 Web: http://www.geos.ed.ac.uk/homes/s0455078 ______________________________________________ [email protected] 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.
