Re: [Haskell-beginners] strange behaviour : computing lowest divisor

Thanks, that seems to have fixed it. On Wed, Dec 29, 2010 at 5:46 PM, Lyndon Maydwell wrote:

Try with Integer rather than Int. Might be an overflow issue...

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HI, I have written(copied) a small piece of code which finds the lowest

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of am integer (greater than 1)

the code is here

ld::Int->Int ld n = ld' 2 n where ld' i n | rem n i == 0 = i | i^2 > n = n | otherwise = ld' (i+1) n

now it seems to work fine for small numbers but for a big number we get

*Main> ld 278970415063349480483707695 7

the number is obviously divisible by 5 , so where is the anomaly ?

Thanks, Abhijit On Wed, Dec 29, 2010 at 2:52 PM, Alex Rozenshteyn wrote:

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I'm trying to understand the technique referred to as "tying the knot", but documentation on the internet seems to be much sparser and more

obtuse

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than I like.

So I'm asking here.

As far as I understand, "tying the knot" refers to a way of using laziness to implement something like references in a purely functional way.

I'm trying to write a toy simulation: I have a population :: [Person] I want to collect a random subset of possible pairs of distinct people. So I go to each person in the population and select a subset of the

On Wed, Dec 29, 2010 at 5:32 PM, Abhijit Ray wrote: divisor people

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after him/her in the list; these are pairs in which s/he is the first element.

I want to then be able to ask for all pairs in which a person is the first or the second element. I could give each person a unique id, but it seems like tying the knot is a valid way to implement this.

Please correct me if I am misunderstanding.

Thank you.

-- Alex R

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