/// <summary>
/// True arbitrary-precision mod operation
/// </summary>
/// <param name="n1"></param>
/// <param name="n2"></param>
/// <returns></returns>
public static BigInt Mod(BigInt n1, BigInt n2)
{
if (n1.digitArray.Length != n2.digitArray.Length) MakeSafe(ref n1, ref n2);
BigInt res = new BigInt(n1);
res.Mod(n2);
return res;
}