curveball function

Randomize an incidence matrix or bipartite graph using the curveball algorithm

curveball randomizes an incidence matrix or bipartite graph, preserving the row and column sums

curveball(M, trades = 5 * nrow(M), class = NULL)

Arguments

• M: a binary matrix of class matrix or Matrix, or a bipartite graph of class igraph.
• trades: integer: number of trades; the default is 5 * nrow(M) (approx. mixing time)
• class: string: Return object as matrix, Matrix, igraph. If NULL, object is returned in the same class as M.

Returns

An incidence matrix of class matrix or Matrix, or a bipartite graph of class igraph.

Details

Strona et al. (2014) provided an initial implementation of the Curveball algorithm in R. curveball() is a modified R implementation that is slightly more efficient. For an even more efficient algorithm, see backbone::fastball().

Examples

M <- incidence.from.probability(5,5,.5)  #A matrix
Mrand <- curveball(M)  #Random matrix with same row/col sums
all.equal(rowSums(M), rowSums(curveball(M)))
all.equal(colSums(M), colSums(curveball(M)))

References

Strona, Giovanni, Domenico Nappo, Francesco Boccacci, Simone Fattorini, and Jesus San-Miguel-Ayanz. 2014. A Fast and Unbiased Procedure to Randomize Ecological Binary Matrices with Fixed Row and Column Totals. Nature Communications, 5, 4114. tools:::Rd_expr_doi("10.1038/ncomms5114")

Godard, Karl and Neal, Zachary P. 2022. fastball: A fast algorithm to sample bipartite graphs with fixed degree sequences. list("arXiv:2112.04017")

Neal, Z. P. 2022. incidentally: An R package to generate incidence matrices and bipartite graphs. OSF Preprints tools:::Rd_expr_doi("10.31219/osf.io/ectms")