public bool MillerRabin(Int64 n, Int64 accuracy = 100)
{
if (n < 1)
{
throw new ArgumentException("The number must be natural");
}
if (n == 1 || n == 2)
{
return(true);
}
if (n % 2 == 0)
{
return(false);
}
Tuple <Int64, Int64> tAnds = FindT(n);
Random rnd = new Random();
for (Int64 i = 1; i <= accuracy; ++i)
{
Int64 a = rnd.Next(2, (int)n - 2);
Int64 x = BinaryMath.PowByModulo(a, tAnds.Item1, n);
if (x == 1 || x == n - 1)
{
continue;
}
bool isCont = false;
for (Int64 j = 0; j < tAnds.Item2 - 1; ++j)
{
x = (x * x) % n;
if (x == 1)
{
return(false);
}
if (x == n - 1)
{
isCont = true;
}
}
if (isCont)
{
continue;
}
return(false);
}
return(true);
}
private Tuple <Int64, Int64> FindT(Int64 n)
{
Tuple <Int64, Int64> res;
for (Int64 i = 60; i >= 1; --i)
{
if ((n - 1) % BinaryMath.Pow(2, i) == 0)
{
return(new Tuple <Int64, Int64>((n - 1) / BinaryMath.Pow(2, i), i));
}
}
return(null);
}
