Thanks John and Rudiger, Yes, I can and will rewrite the code... I was just shocked at how slow eval was.
-Joe On Wed, Jul 18, 2012 at 10:52 PM, Rüdiger Asche <r...@ruediger-asche.de>wrote: > ** > yes it is: > > (define thunk1 (lambda () (/ 100 10))) > (define thunk2 (lambda () (eval '(/ 100 10)))) > (define iterate (lambda (ct thunk) > (if (zero? ct) > #t (begin (thunk) (iterate (- ct 1) thunk))))) > > (time (iterate 1000000 thunk1)) > => cpu time: 15 real time: 16 gc time: 0 > > (time (iterate 1000000 thunk2)) > => cpu time: 21110 real time: 21125 gc time: 436 > > > > > ----- Original Message ----- > *From:* Joe Gilray <jgil...@gmail.com> > *To:* Racket mailing list <users@racket-lang.org> > *Sent:* Thursday, July 19, 2012 7:15 AM > *Subject:* [racket] Is eval very slow? > > Hi, > > I've written some code that uses eval: > > (define ops (list * / + -)) > (define digits '(1 2 3 4 5)) > (for ([dl (combinations 4 digits)]) > (define lst '()) > (for ([d (permute-all dl)]) > (for* ([o1 ops] [o2 ops] [o3 ops]) > (unless (and (eq? o1 /) (zero? (eval (list o2 (second d) (list o3 > (third d) (fourth d)))))) ; avoid divide by zero > (define val (eval (list o1 (first d) (list o2 (second d) (list > o3 (third d) (fourth d)))))) > (when (>= val 1) (set! lst (cons val lst)))) ... > > It runs very, very slowly. Am I doing something wrong? Is there a way to > speed up eval? > > Thanks, > -Joe > > ------------------------------ > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users > >
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