Difference between revisions of "Talk:Prime numbers"
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[[User:MathematicalOrchid|MathematicalOrchid]] 16:41, 5 February 2007 (UTC) |
[[User:MathematicalOrchid|MathematicalOrchid]] 16:41, 5 February 2007 (UTC) |
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+ | a composite can indeed have factors greater than its square root, and indeed most do. what you mean is that a composite will definitely have at least one factor smaller-equal than its square root. |
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+ | why not use <hask>(\x -> n > x*x)</hask> --[[User:JohannesAhlmann|Johannes Ahlmann]] 21:18, 5 February 2007 (UTC) |
Revision as of 21:18, 5 February 2007
Here's an interesting question: will the program go faster if we replace all those (n >)
expressions with (\x -> floor (sqrt n) > x)
?
On one hand, a composite integer cannot possess a factor greater than its square root.
On the other hand, since the list we're looking through contains all possible prime numbers, we are guaranteed to find a factor or an exact match eventually, so do we need the takeWhile
at all?
Throwing this over to somebody with a bigger brain than me...
MathematicalOrchid 16:41, 5 February 2007 (UTC)
a composite can indeed have factors greater than its square root, and indeed most do. what you mean is that a composite will definitely have at least one factor smaller-equal than its square root.
why not use (\x -> n > x*x)
--Johannes Ahlmann 21:18, 5 February 2007 (UTC)