Constrained matrix permutation #74

To do

• Literature search, this looks promising:
  • C. J. Carstens, Proof of uniform sampling of binary matrices with fixed row sums and column sums for the fast Curveball algorithm. PHYSICAL REVIEW E 91, 042812 (2015)
  • Snijders, T.A.B., Enumeration and simulation methods for 0-1 matrices with given marginals. Psychometrika, 56 (1991), 397-417. (this enumerates all possible matrices -- probably not what we want)
• After finding a proof of uniformity we're happy with, code it up
• Compare distribution of some test statistic between this method and @stefanv's code. Test statistic could be total number of pairs of sharks observed together