I'm looking for a reference on how to sample uniformly (and preferably efficiently, elegantly, etc.) from the vertices of a polytope. I gather that enumerating vertices is hard. I also note the MO questions Uniformly Sampling from Convex Polytopes and Is it possible to sample uniformly on the surface of a high-dimensional polytope?. A bit of poking around Google Scholar hasn't turned anything up.

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    $\begingroup$ I recently asked a question that turned out to be equivalent: cstheory.stackexchange.com/questions/42705/… I found some interesting references, but nothing definitive yet. $\endgroup$ – Lorenzo Najt Apr 14 '19 at 4:30
  • $\begingroup$ I think I was able to show it is NP-hard. Take a look and see if you believe my argument. :-) $\endgroup$ – Lorenzo Najt Apr 20 '19 at 5:17
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    $\begingroup$ It is $NP$-hard. See updated answer. $\endgroup$ – Lorenzo Najt Nov 13 '19 at 0:22
  • $\begingroup$ @LorenzoNajt- Thanks for the update! $\endgroup$ – Steve Huntsman Nov 13 '19 at 15:37

Here is one efficient approach, performing a random walk with a rapid mixing time, that has been implemented for a particular class of polytopes, but which might well be adaptable to a more general setting: Random Walks on the Vertices of Transportation Polytopes (2008).

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  • $\begingroup$ Interesting bit from the first page: "Markov chain Monte Carlo (MCMC) has not been well explored as a means of sampling, or approximately counting, vertices of general polytopes." $\endgroup$ – Steve Huntsman Jan 2 '19 at 14:52
  • $\begingroup$ ...and from the conclusions: "The question of whether we can sample vertices of a general [transportation polytope], when the number of sources is not constant, is still open." $\endgroup$ – Steve Huntsman Jan 2 '19 at 14:53

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