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Prime testing

Simple check if a number is prime. See also http://fssnip.net/2w.

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let isPrime n =
    match n with
    | _ when n > 3 && (n % 2 = 0 || n % 3 = 0) -> false
    | _ ->
        let maxDiv = int(System.Math.Sqrt(float n)) + 1
        let rec f d i = 
            if d > maxDiv then 
                true
            else
                if n % d = 0 then 
                    false
                else
                    f (d + i) (6 - i)     
        f 5 2
val isPrime : n:int -> bool

Full name: Script.isPrime
val n : int
val maxDiv : int
Multiple items
val int : value:'T -> int (requires member op_Explicit)

Full name: Microsoft.FSharp.Core.Operators.int

--------------------
type int = int32

Full name: Microsoft.FSharp.Core.int

--------------------
type int<'Measure> = int

Full name: Microsoft.FSharp.Core.int<_>
namespace System
type Math =
  static val PI : float
  static val E : float
  static member Abs : value:sbyte -> sbyte + 6 overloads
  static member Acos : d:float -> float
  static member Asin : d:float -> float
  static member Atan : d:float -> float
  static member Atan2 : y:float * x:float -> float
  static member BigMul : a:int * b:int -> int64
  static member Ceiling : d:decimal -> decimal + 1 overload
  static member Cos : d:float -> float
  ...

Full name: System.Math
System.Math.Sqrt(d: float) : float
Multiple items
val float : value:'T -> float (requires member op_Explicit)

Full name: Microsoft.FSharp.Core.Operators.float

--------------------
type float = System.Double

Full name: Microsoft.FSharp.Core.float

--------------------
type float<'Measure> = float

Full name: Microsoft.FSharp.Core.float<_>
val f : (int -> int -> bool)
val d : int
val i : int
Raw view Test code New version

More information

Link:http://fssnip.net/7E
Posted:12 years ago
Author:d95danb
Tags: prime testing , primes , math

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