calculate_IBS
calculate_IBS(snpdata, mat.name="GT")
calculate_IBS is a function that generates the dissimilarity matrix (1-IBS where IBS is the identity by state that represents the proportion of similar loci between any given pair of samples)
snpdata: an object of class SNPdata
mat.name: the name of the genotype table to be used for IBS calculation
a SNPdata object with an additional field: IBS. This is an N*N matrix (where N is the number of samples)