# Randomizations

The methods for matrix randomizations defined in RandomBooleanMatrices are defined for the SpatialEcology type ComMatrix and Assemblage. These methods randomize the cells of a presence-absence matrix while keeping row and column sums constant - a very widely used method for randomizing ecological communities for null model analysis (see e.g. Miklós, I. and Podani, J. (2004), RANDOMIZATION OF PRESENCE–ABSENCE MATRICES: COMMENTS AND NEW ALGORITHMS. Ecology, 85: 86-92.

To simulate random communities, you define a matrixrandomizer object on your type - you can then simulate from it using rand and rand!. For example, using the amph object from the tutorial @example tutorial using Random rmg = matrixrandomizer(amph) newcomm = rand!(rmg)

newcomm is then a new Assemblage object with the same properties as amph`, but with all co-occurrences randomized.