{"action":"created","issue":{"url":"https://api.github.com/repos/JuliaMath/FFTW.jl/issues/62","repository_url":"https://api.github.com/repos/JuliaMath/FFTW.jl","labels_url":"https://api.github.com/repos/JuliaMath/FFTW.jl/issues/62/labels{/name}","comments_url":"https://api.github.com/repos/JuliaMath/FFTW.jl/issues/62/comments","events_url":"https://api.github.com/repos/JuliaMath/FFTW.jl/issues/62/events","html_url":"https://github.com/JuliaMath/FFTW.jl/issues/62","id":300118347,"number":62,"title":"FFTW.r2r slow","user":{"login":"skeletonyk","id":14181817,"avatar_url":"https://avatars3.githubusercontent.com/u/14181817?v=4","gravatar_id":"","url":"https://api.github.com/users/skeletonyk","html_url":"https://github.com/skeletonyk","followers_url":"https://api.github.com/users/skeletonyk/followers","following_url":"https://api.github.com/users/skeletonyk/following{/other_user}","gists_url":"https://api.github.com/users/skeletonyk/gists{/gist_id}","starred_url":"https://api.github.com/users/skeletonyk/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/skeletonyk/subscriptions","organizations_url":"https://api.github.com/users/skeletonyk/orgs","repos_url":"https://api.github.com/users/skeletonyk/repos","events_url":"https://api.github.com/users/skeletonyk/events{/privacy}","received_events_url":"https://api.github.com/users/skeletonyk/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"assignees":[],"milestone":null,"comments":5,"created_at":"2018-02-26T05:56:49Z","updated_at":"2018-02-27T01:22:46Z","closed_at":null,"author_association":"NONE","body":"I was trying to use discrete sine transform which is not in the standard Base library (why is cosine transform there~?) so I turned to use fftw.r2r with FFTW.RODFT00 flag. It turned out to be 2x slower the Matlab dst somehow. Does anyone have the same issue? \r\n\r\nThis is the result for 2D transform\r\nJulia:\r\n  @time ainv(rand(1000,1000))\r\n  0.612343 seconds (204 allocations: 30.528 MiB, 0.86% gc time)\r\n\r\nMatlab:\r\n Elapsed time is 0.140380 seconds.\r\n\r\nPS I turned the multithreading on in Julia already. \r\n\r\nThanks!\r\n"},"comment":{"url":"https://api.github.com/repos/JuliaMath/FFTW.jl/issues/comments/368712727","html_url":"https://github.com/JuliaMath/FFTW.jl/issues/62#issuecomment-368712727","issue_url":"https://api.github.com/repos/JuliaMath/FFTW.jl/issues/62","id":368712727,"user":{"login":"skeletonyk","id":14181817,"avatar_url":"https://avatars3.githubusercontent.com/u/14181817?v=4","gravatar_id":"","url":"https://api.github.com/users/skeletonyk","html_url":"https://github.com/skeletonyk","followers_url":"https://api.github.com/users/skeletonyk/followers","following_url":"https://api.github.com/users/skeletonyk/following{/other_user}","gists_url":"https://api.github.com/users/skeletonyk/gists{/gist_id}","starred_url":"https://api.github.com/users/skeletonyk/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/skeletonyk/subscriptions","organizations_url":"https://api.github.com/users/skeletonyk/orgs","repos_url":"https://api.github.com/users/skeletonyk/repos","events_url":"https://api.github.com/users/skeletonyk/events{/privacy}","received_events_url":"https://api.github.com/users/skeletonyk/received_events","type":"User","site_admin":false},"created_at":"2018-02-27T01:22:46Z","updated_at":"2018-02-27T01:22:46Z","author_association":"NONE","body":"Thanks for the detailed reply and the tests. I didn't know I can use @btime before. Thanks. \r\n\r\nI did run it a few times to avoid the compilation time. I tried the same code of yours and the results are:\r\n\r\n  722.920 μs (53 allocations: 1.00 MiB)\r\n  223.660 μs (4 allocations: 1.00 MiB)\r\n  15.340 ms (2 allocations: 256.08 KiB)\r\n\r\nSomething is not right with my r2r haha. Can I ask which version of Julia are you using? Also did you build FFTW to use MKL library? "}}
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