Hey Mark, This latest release broke all the Clojure 1.2.0 and 1.2.1 builds for math.combinatorics (http://build.clojure.org/job/math.combinatorics-test-matrix/129/), I think due to using an assert arity that didn't exist then? We should either change the min version for the test matrix or modify the code to make it compatible. I can take care of the former for you if needed.
Alex On Tuesday, March 17, 2015 at 10:58:45 PM UTC-5, puzzler wrote: > > For a while now, the permutations function in the combinatorics library > has had special handling for lists with duplicate items. > > Example: (permutations [1 2 3]) -> ((1 2 3) (1 3 2) (2 1 3) (2 3 1) (3 1 > 2) (3 2 1)) > Example: (permutations [1 1 2]) -> ((1 1 2) (1 2 1) (2 1 1)) > > The new release, version 0.1.0 extends this intelligent handling of > duplicate items to combinations and subsets. > > There are straightforward computations for counting permutations, > combinations, and subsets of n distinct items -- so straightforward it > never seemed worth adding to the library. However, now with the special > handling of duplicates, it seems very natural to want to know things like: > > (count-permutations [1 1 1 2 2 2]) -> 20 ;not 6! > > So I've added count-permutations, count-combinations, and count-subsets > which do the obvious things for lists with no duplicates, but for lists > with duplicates, computes the count taking into account the special > handling of lists with duplicates. It computes these counts directly, not > by iterating through the actual stream of permutations/combinations/subsets. > > Similarly, there is now a way to compute the nth > permutation/combination/subset without iterating through the result stream. > > I've also added two new permutation-related functions: > drop-permutations lets you efficiently skip over some number of > permutations before starting the stream of results. > > permutation-index is like nth-permutation in reverse - from a scrambled > sortable collection, it will tell you how far into the lexicographic stream > of permutations it is located (computed directly without iterating through > the stream). > > So now you can easily find out in the blink of an eye, for example, that > "clojurecombinatoricsrocks" is the 169001484919860315564th permutation > (0-based) of "abcccceiijklmnoooorrrsstu" > > Didn't your life feel empty before learning that important fact? > > Enjoy the new functionality! > > https://github.com/clojure/math.combinatorics > > --Mark Engelberg > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en --- You received this message because you are subscribed to the Google Groups "Clojure" group. To unsubscribe from this group and stop receiving emails from it, send an email to clojure+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
