Legendre prime counting function: Difference between revisions
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GordonBGood (talk | contribs) m (→Non Memoized Haskell Versions: Haskell: improve comments...) |
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'''The Non-Recursive Partial Sieving Algorithm''' |
'''The Non-Recursive Partial Sieving Algorithm''' |
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Just substitute the following Haskell code for the `countPrimes` function above to enjoy the further gain in speed: |
Just substitute the following Haskell code for the `countPrimes` function above to enjoy the further gain in speed; this version may appear to be recursive to those unfamiliar with Functional Programming (FP) implementations but FP generally turns all function recursions in tail-call position (which all of these are) into the same compiled code as a simple loop in other languages: |
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<syntaxhighlight lang="haskell"> |
<syntaxhighlight lang="haskell">countPrimes :: Word64 -> Int64 |
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countPrimes n = |
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if n < 3 then (if n < 2 then 0 else 1) else |
if n < 3 then (if n < 2 then 0 else 1) else |
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let |
let |
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