public static bool IsPrimeLowNumber(int n, int k)
{
Random rn = new Random((int)DateTime.Now.Ticks);
for (int i = 0; i < k; i++)
{
int a = rn.Next(0, n - 1);
if (AbvMath.GetGCDBinary(n, a) > 1)
{
return(false);
}
BigInteger buf = BigInteger.ModPow(a, (n - 1) >> 1, n);
switch (AbvMath.GetLegendreSymbolValue(a, n))
{
case 0:
return(false);
case 1:
if (buf != 1)
{
return(false);
}
break;
case -1:
if (buf != n - 1)
{
return(false);
}
break;
}
}
return(true);
}
/// <summary>
/// Test is it num prime
/// </summary>
/// <param name="n">Number to test</param>
/// <param name="k">Count of iterations (accuary = 1-2^-k)</param>
/// <returns>true if n prime and false otherwise</returns>
public static bool IsPrime(ref BigInteger n, int k)
{
Random rn = new Random((int)DateTime.Now.Ticks);
int min = 0x7fffffff;
if (n < min)
{
min = int.Parse(n.ToString()) - 1;
}
for (int i = 0; i < k; i++)
{
BigInteger a = rn.Next(0, min);
if (AbvMath.GetGCDBinary(n, a) > 1)
{
return(false);
}
BigInteger buf = BigInteger.ModPow(a, (n - 1) >> 1, n);
switch (AbvMath.GetLegendreSymbolValue(a, n))
{
case 0:
return(false);
case 1:
if (buf != 1)
{
return(false);
}
break;
case -1:
if (buf != n - 1)
{
return(false);
}
break;
}
}
return(true);
}
private bool PrivateIsPrime(ref BigInteger n, int k)
{
Random rn = new Random();
BigInteger one = BigInteger.One;
for (_CurrentState = 0; _CurrentState < k; _CurrentState++)
{
OnStatusChanged(this);
BigInteger a = rn.Next(0, 2147000000);
if (AbvMath.GetGCDBinary(n, a) > 1)
{
return(false);
}
BigInteger buf = BigInteger.ModPow(a, (n - 1) >> 1, n);
switch (AbvMath.GetJacobiSymbolValue(a, n))
{
case 0:
return(false);
case 1:
if (buf != 1)
{
return(false);
}
break;
case -1:
if (buf != n - 1)
{
return(false);
}
break;
}
}
return(true);
}
