What happened to bignum support? (clojure 1.3.0)
Greetings, Clojure community. I've been playing around with clojure, and just downloaded 1.3.0. Here's a REPL session, wherein I define a power-of-two function, and apply it a couple of times. lecturer-01:clojure-1.3.0 kangas$ java -cp clojure-1.3.0.jar clojure.main Clojure 1.3.0 user= (defn pow2 [n] (loop [n n, p 1] (if (zero? n) p (recur (dec n) (+ p p)) ))) #'user/pow2 user= (pow2 62) 4611686018427387904 user= (pow2 63) ArithmeticException integer overflow clojure.lang.Numbers.throwIntOverflow (Numbers.java:1374) user= Previous versions would silently, automagically convert to bignums and give me the answer I wanted. Is clojure-1.3.0 too serious, enterprisy, and Java-like for this sort of thing? I found no clue in the list of changes. thanks, George -- 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
Re: What happened to bignum support? (clojure 1.3.0)
Greetings, Clojure community. I've been playing around with clojure, and just downloaded 1.3.0. Here's a REPL session, wherein I define a power-of-two function, and apply it a couple of times. lecturer-01:clojure-1.3.0 kangas$ java -cp clojure-1.3.0.jar clojure.main Clojure 1.3.0 user= (defn pow2 [n] (loop [n n, p 1] (if (zero? n) p (recur (dec n) (+ p p)) ))) #'user/pow2 user= (pow2 62) 4611686018427387904 user= (pow2 63) ArithmeticException integer overflow clojure.lang.Numbers.throwIntOverflow (Numbers.java:1374) user= Previous versions would silently, automagically convert to bignums and give me the answer I wanted. Is clojure-1.3.0 too serious, enterprisy, and Java-like for this sort of thing? I found no clue in the list of changes. This has to do with the primitive math support in Clojure 1.3. Every number is now a primitive unless otherwise mentioned. `(pow2 63)` is throwing an exception now because 63 is a primitive int. If you want `pow2` to work well on large numbers you will have to use the arbitrary precision math functions like +', -', *', /', etc. You can also take advantage of BigInteger contagion by switching the initial value of p to 1N instead of 1. Thus you can write your function in two ways - ;;; Use arbitrary precision add function. Will return BigInteger when needed. (defn pow2 [n] (loop [n n, p 1] (if (zero? n) p (recur (dec n) (+' p p) ; +' instead of + ;;; Utilize BigInteger contagion. Will always return BigInteger. (defn pow2 [n] (loop [n n, p 1N] ; this is different (if (zero? n) p (recur (dec n) (+ p p) I hope that helps. Regards, BG -- Baishampayan Ghose b.ghose at gmail.com -- 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
Re: What happened to bignum support? (clojure 1.3.0)
Hi George, On 25 Sep 2011, at 22:25, George Kangas wrote: Previous versions would silently, automagically convert to bignums and give me the answer I wanted. Is clojure-1.3.0 too serious, enterprisy, and Java-like for this sort of thing? I found no clue in the list of changes. In addition to Baishampayan's excellent answer, it might also be useful to point you to the relevant documentation. The 1.3 changelist mentions Enhanced Primitive Support (https://github.com/clojure/clojure/blob/master/changes.txt#L75) which points to the following two pages: http://dev.clojure.org/display/doc/Enhanced+Primitive+Support http://dev.clojure.org/display/doc/Documentation+for+1.3+Numerics which may be helpful for you. Sam --- http://sam.aaron.name -- 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
Re: What happened to bignum support? (clojure 1.3.0)
Thanks, Baishampayan and Sam! Since so little effort is required to get the BigInt behavior, you'll all be relieved to hear that I Approve of This Change. Should I ever need high performance from Clojure, I'll actually be happy about it. Notwithstanding the snarking tone of my original post. George -- 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
