Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.lang.python > #101821
| From | Chris Angelico <rosuav@gmail.com> |
|---|---|
| Newsgroups | comp.lang.python |
| Subject | Re: Keen eyes |
| Date | 2016-01-17 09:30 +1100 |
| Message-ID | <mailman.47.1452983435.15297.python-list@python.org> (permalink) |
| References | <d8e5eaf4-c59f-4635-8e73-f4a9a1a84877@googlegroups.com> |
On Sun, Jan 17, 2016 at 9:23 AM, <jonas.thornvall@gmail.com> wrote:
> function factor_it(i){
> prime=true;
> sqroot=Math.floor(Math.sqrt(i));
> for (j=2;j<sqroot;j++){ k=i/j; prime=!Number.isInteger(k); if (prime) {return prime}}
> return prime;
> }
A couple of potential problems here. The first thing that comes to
mind is that floating point inaccuracy is going to bite you long
before the numbers "seem huge" to someone who's thinking about 2**53.
The second is an off-by-one error: a perfect square may come up as
prime.
Check for those and see how it looks.
Also, check your double-use of the 'prime' variable, which also
appears to be global here.
ChrisA
Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
Keen eyes jonas.thornvall@gmail.com - 2016-01-16 14:23 -0800
Re: Keen eyes Chris Angelico <rosuav@gmail.com> - 2016-01-17 09:30 +1100
Re: Keen eyes jonas.thornvall@gmail.com - 2016-01-16 14:55 -0800
Re: Keen eyes jonas.thornvall@gmail.com - 2016-01-16 15:25 -0800
Re: Keen eyes Steven D'Aprano <steve@pearwood.info> - 2016-01-17 18:10 +1100
Re: Keen eyes Ian Kelly <ian.g.kelly@gmail.com> - 2016-01-17 00:37 -0700
Re: Keen eyes Paul Rubin <no.email@nospam.invalid> - 2016-01-16 23:52 -0800
Re: Keen eyes Chris Angelico <rosuav@gmail.com> - 2016-01-17 19:25 +1100
Re: Keen eyes BartC <bc@freeuk.com> - 2016-01-17 11:17 +0000
Re: Keen eyes Chris Angelico <rosuav@gmail.com> - 2016-01-17 22:32 +1100
csiph-web