h.isprime

来自「强大的数学工具包」· ISPRIME 代码 · 共 36 行

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        "is prime ?"
        SYNTAX: X = isprime(a)

        a is an expression whose value is a positive integer. 

        isprime decides if a is prime and displays the 
        following messages:
        - a is pseudoprime      
          (a passed several Miller-Rabin pseudoprimality tests.)
        - a is prime (a-1)
          (The primality of a was proved by factoring a-1.)
        - a is prime    h(-d)=r
          (The primality of a was proved by factoring the
           point order of an elliptic curve over Z/aZ which has
           complex multiplication in the ring of integers of
           the imaginary quadratic number field Q(sqrt(-d)).
           The class number of Q(sqrt(-d)) is r.) 
        X=1 if a is a prime; X=0 if a is not a prime; X=(-1) if
        a is a pseudoprime.


        Example 1: (correct)

                p = isprime( 6220506277488749 )


        Example 2: (incorrect)

                isprime( -34523454 )

_ERR_NR_019