Given that partitions2.rkt is written in TR, it shouldn't have to go through a contract boundary to use `exact-zero?` (which is also written in TR). The contract profiler does not observe any time spent in contracts, which supports that hypothesis.
How did you discover that `exact-zero?` was wrapped? I'm wondering whether we looked at different versions of the code (I ran the version Jens attached to his email), or whether there's a bug in the contract profiler. Vincent At Sun, 29 Jun 2014 07:47:24 +0100, Matthew Flatt wrote: > > It looks like "partitions2.rkt" ends up calling a contract-wrapped > variant of `exact-zero?`. If I change `ref!` to > > (define (ref! n thnk) > (let ([v (vector-ref cache n)]) > (if (zero? v) > (let ([new-v (thnk)]) > (vector-set! cache n new-v) > new-v) > v))) > > then "partitions2.rkt" is much faster. > > At Sat, 28 Jun 2014 12:06:34 +0200, Jens Axel Søgaard wrote: > > Hi, > > > > I have converted your code to Typed Racket and made two versions. > > The first version use a hash as cache and the second version us a vector. > > > > Timings show that the vector version is 1.5 to 2 times slower than the > > hash version. > > > > I don't understand this. Is there anything that can be done to improve it? > > > > The two versions can be seen here in color: > > > > http://pasterack.org/pastes/12166 > > http://pasterack.org/pastes/16085 > > > > They are also attached. > > > > I used (time (begin (partitions 50000) 0)) as benchmark. > > > > > > > > > > 2014-06-28 9:54 GMT+02:00 Jos Koot <jos.k...@gmail.com>: > > > Sorry, forgot to post the following to the users list. > > > > > > Hi, > > > count partitions, much faster and exact. > > > You may want to put the hash or part of it within function p such as to > > > avoid spllling much memory. > > > Jos > > > > > > #lang racket > > > > > > (require math/number-theory) > > > > > > (define p-hash (make-hash '((0 . 1)))) > > > > > > (define (p n) > > > (hash-ref! p-hash n > > > (λ () > > > (+ > > > (let loop ((k 1) (m (sub1 n)) (s 0)) > > > (if (< m 0) s > > > (loop (add1 k) (- m (add1 (* 3 k))) (if (odd? k) (+ s (p m)) (- s (p > > > m)))))) > > > (let loop ((k -1) (m (- n 2)) (s 0)) > > > (if (< m 0) s > > > (loop (sub1 k) (+ m (* 3 k) -2) (if (odd? k) (+ s (p m)) (- s (p > > > m)))))))))) > > > > > > (time (for ((n (in-range 0 1000))) (p n))) > > > (time (for ((n (in-range 0 1000))) (partitions n))) > > > (void (time (p 10000))) > > > > > > (for/and ((n (in-range 0 1000))) (= (partitions n) (p n))) > > > > > > (read-line) > > > > > > ; results with racket: > > > ; cpu time: 16 real time: 16 gc time: 0 > > > ; cpu time: 8845 real time: 8845 gc time: 111 > > > ; cpu time: 577 real time: 578 gc time: 0 > > > ; #t > > > > > > > > > > > > ____________________ > > > Racket Users list: > > > http://lists.racket-lang.org/users > > > > > > > > -- > > -- > > Jens Axel Søgaard > > > > > > ------------------------------------------------------------------------------ > > [application/octet-stream "partitions2.rkt"] [~/Desktop & open] [~/Temp & > > open] > > > > > > ------------------------------------------------------------------------------ > > [application/octet-stream "partitions1.rkt"] [~/Desktop & open] [~/Temp & > > open] > > ____________________ > > Racket Users list: > > http://lists.racket-lang.org/users > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users ____________________ Racket Users list: http://lists.racket-lang.org/users
