I would be very interested to learn which kind of practical problems these engines can solve? Any real-world examples would help me understand the benefit of this approach. Many greetings John
Am Samstag, 2. Februar 2013 07:44:25 UTC+1 schrieb AtKaaZ: > > seems a bit similar to https://github.com/Prismatic/plumbing > > > On Sat, Feb 2, 2013 at 1:12 AM, Ben Wolfson <wol...@gmail.com<javascript:> > > wrote: > >> ReadyForZero is open-sourcing our library for easily gathering data >> and computing summary measures in a declarative way: >> >> https://github.com/ReadyForZero/babbage >> >> The summary measure functionality allows you to compute multiple >> measures over arbitrary partitions of your input data simultaneously >> and in a single pass. You just say what you want to compute: >> >> > (def my-fields {:y (stats :y count) >> :x (stats :x count) >> :both (stats #(+ (or (:x %) 0) (or (:y %) 0)) count >> sum mean)}) >> >> and the sets that are of interest: >> >> > (def my-sets (-> (sets {:has-y #(contains? % :y}) >> (complement :has-y))) ;; could also take >> intersections, unions >> >> And then run it with some data: >> >> > (calculate my-sets my-fields [{:x 1 :y 2} {:x 10} {:x 4 :y 3} {:x 5}]) >> {:not-has-y >> {:y {:count 0}, :x {:count 2}, :both {:mean 7.5, :sum 15, :count 2}}, >> :has-y >> {:y {:count 2}, :x {:count 2}, :both {:mean 5.0, :sum 10, :count 2}}, >> :all >> {:y {:count 2}, :x {:count 4}, :both {:mean 6.25, :sum 25, :count 4}}} >> >> The functions :x, :y, and #(+ (or (:x %) 0) (or (:y %) 0)) defined in >> the fields map are called once per input element no matter how many >> sets the element contributes to. The function #(contains? % y) is also >> called once per input element, no matter how many unions, >> intersections, complements, etc. the set :has-y contributes to. >> >> A variety of measure functions, and structured means of combining >> them, are supplied; it's also easy to define additional measures. >> >> babbage also supplies a method for running computations structured as >> dependency graphs; this can make gathering the initial data for >> summarizing simpler to express. To give an example that's probably >> familiar from another context: >> >> > (defgraphfn sum [xs] >> (apply + xs)) >> > (defgraphfn sum-squared [xs] >> (sum (map #(* % %) xs))) >> > (defgraphfn count-input :count [xs] >> (count xs)) >> > (defgraphfn mean [count sum] >> (double (/ sum count))) >> > (defgraphfn mean2 [count sum-squared] >> (double (/ sum-squared count))) >> > (defgraphfn variance [mean mean2] >> (- mean2 (* mean mean))) >> > (run-graph {:xs [1 2 3 4]} sum variance sum-squared count-input mean >> mean2) >> {:sum 10 >> :count 4 >> :sum-squared 30 >> :mean 2.5 >> :variance 1.25 >> :mean2 7.5 >> :xs [1 2 3 4]} >> >> Options are provided for parallel, sequential, and lazy computation of >> the elements of the result map, and for resolving the dependency graph >> in advance of running the computation for a given input, either at >> runtime or at compile time. >> >> Please see the README at the github repo for more details. >> >> Enjoy! >> >> -- >> Ben Wolfson >> "Human kind has used its intelligence to vary the flavour of drinks, >> which may be sweet, aromatic, fermented or spirit-based. ... Family >> and social life also offer numerous other occasions to consume drinks >> for pleasure." [Larousse, "Drink" entry] >> >> -- >> -- >> You received this message because you are subscribed to the Google >> Groups "Clojure" group. >> To post to this group, send email to clo...@googlegroups.com<javascript:> >> Note that posts from new members are moderated - please be patient with >> your first post. >> To unsubscribe from this group, send email to >> clojure+u...@googlegroups.com <javascript:> >> 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+u...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> >> > > > -- > Please correct me if I'm wrong or incomplete, > even if you think I'll subconsciously hate it. > > -- -- 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/groups/opt_out.
