{"action":"created","issue":{"url":"https://api.github.com/repos/JuliaLang/IndexingBenchmarks.jl/issues/6","repository_url":"https://api.github.com/repos/JuliaLang/IndexingBenchmarks.jl","labels_url":"https://api.github.com/repos/JuliaLang/IndexingBenchmarks.jl/issues/6/labels{/name}","comments_url":"https://api.github.com/repos/JuliaLang/IndexingBenchmarks.jl/issues/6/comments","events_url":"https://api.github.com/repos/JuliaLang/IndexingBenchmarks.jl/issues/6/events","html_url":"https://github.com/JuliaLang/IndexingBenchmarks.jl/pull/6","id":136659677,"number":6,"title":"Initial implementation of butterfly FFT with various ways of indexing","user":{"login":"daanhb","id":7403822,"avatar_url":"https://avatars.githubusercontent.com/u/7403822?v=3","gravatar_id":"","url":"https://api.github.com/users/daanhb","html_url":"https://github.com/daanhb","followers_url":"https://api.github.com/users/daanhb/followers","following_url":"https://api.github.com/users/daanhb/following{/other_user}","gists_url":"https://api.github.com/users/daanhb/gists{/gist_id}","starred_url":"https://api.github.com/users/daanhb/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/daanhb/subscriptions","organizations_url":"https://api.github.com/users/daanhb/orgs","repos_url":"https://api.github.com/users/daanhb/repos","events_url":"https://api.github.com/users/daanhb/events{/privacy}","received_events_url":"https://api.github.com/users/daanhb/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":1,"created_at":"2016-02-26T10:42:21Z","updated_at":"2016-02-26T12:51:08Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/JuliaLang/IndexingBenchmarks.jl/pulls/6","html_url":"https://github.com/JuliaLang/IndexingBenchmarks.jl/pull/6","diff_url":"https://github.com/JuliaLang/IndexingBenchmarks.jl/pull/6.diff","patch_url":"https://github.com/JuliaLang/IndexingBenchmarks.jl/pull/6.patch"},"body":"This test is a comparison of several naive implementations of the recursive butterfly algorithm for the FFT. Large numbers of views are being created in the recursion. Currently, the cost of the actual computations seems to be dominant over the overhead of creating views. Whether data is being copied or not, does not seem to matter much. \r\n\r\nThe example does show that views allocate memory (quite a lot, in this case). The test compares implementations where all data is being copied, where views/subs are created, or where views are simulated manually by passing around either strides or ranges as extra parameters. The latter approach does not allocate memory.\r\n\r\nPerhaps by optimizing the implementation (precomputing twiddle factors comes to mind), the difference between the various ways of indexing can be made more pronounced."},"comment":{"url":"https://api.github.com/repos/JuliaLang/IndexingBenchmarks.jl/issues/comments/189262426","html_url":"https://github.com/JuliaLang/IndexingBenchmarks.jl/pull/6#issuecomment-189262426","issue_url":"https://api.github.com/repos/JuliaLang/IndexingBenchmarks.jl/issues/6","id":189262426,"user":{"login":"stevengj","id":2913679,"avatar_url":"https://avatars.githubusercontent.com/u/2913679?v=3","gravatar_id":"","url":"https://api.github.com/users/stevengj","html_url":"https://github.com/stevengj","followers_url":"https://api.github.com/users/stevengj/followers","following_url":"https://api.github.com/users/stevengj/following{/other_user}","gists_url":"https://api.github.com/users/stevengj/gists{/gist_id}","starred_url":"https://api.github.com/users/stevengj/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/stevengj/subscriptions","organizations_url":"https://api.github.com/users/stevengj/orgs","repos_url":"https://api.github.com/users/stevengj/repos","events_url":"https://api.github.com/users/stevengj/events{/privacy}","received_events_url":"https://api.github.com/users/stevengj/received_events","type":"User","site_admin":false},"created_at":"2016-02-26T12:51:08Z","updated_at":"2016-02-26T12:51:08Z","body":"Might be worthwhile to test some simplified version of my pure-Julia FFT from JuliaLang/julia#6193 (@yuyichao has an updated version of this somewhere, I forget where), too; we need to have benchmarks of optimized code too."}}