public static List <BigInteger> LoadPrimes()
{
if (!Directory.Exists(basePath))
{
Directory.CreateDirectory(basePath);
}
List <BigInteger> result = new List <BigInteger>();
try
{
using (BinaryReader reader = new BinaryReader(File.Open(basePath + "PrimeDatabase.savedata", FileMode.Open)))
{
int length = reader.ReadInt32();
for (int i = 0; i < length; i++)
{
result.Add(MathExtras.ReadBigInteger(reader));
}
}
}
catch (FileNotFoundException e)
{
Console.WriteLine("Error loading Primes");
return(new List <BigInteger>());
}
return(result);
}
private static List <BigInteger> ReadFactors(BinaryReader reader)
{
List <BigInteger> factors = new List <BigInteger>();
int count = reader.ReadInt32();
for (int i = 0; i < count; i++)
{
factors.Add(MathExtras.ReadBigInteger(reader));
}
return(factors);
}
public static void Write(this BigInteger number, BinaryWriter writer)
{
MathExtras.WriteBigInteger(number, writer);
}
public static List <BigInteger> Factorize(this BigInteger number)
{
if (number.BitCount > 10 && MathExtras.MillerTest(number))
{
// it's prime already!
return(new List <BigInteger>());
}
List <BigInteger> factors = new List <BigInteger>();
int next = 0;
while (number > 1)
{
if (Program.primes.Count <= next)
{
// out of primes
// Calculations concluded that number number is prime
if (MathExtras.MillerTest(number))
{
factors.Add(number);
return(factors);
}
BigInteger sqrt = BigInteger.Sqrt(number);
if (sqrt * sqrt == number)
{
// Calculations concluded that number has two factors of sqrt
if (MathExtras.MillerTest(sqrt))
{
// and they are prime
factors.Add(sqrt);
factors.Add(sqrt);
}
else
{
// and they are composite
factors.Add(-sqrt);
factors.Add(-sqrt);
}
continue;
}
// no more factors can be found
factors.Add(-number);
return(factors);
/*
* MathExtras.PrimeFactorizationResult res = MathExtras.PollardsRho(number);
* switch (res.result)
* {
* case MathExtras.PrimeFactorizationResultEvaluation.FactorFound:
* // Calculations concluded that number has a factor of res.primeFactor
* factors.Add(res.primeFactor);
* number /= res.primeFactor;
* continue;
*
* case MathExtras.PrimeFactorizationResultEvaluation.Prime:
* // Calculations concluded that number number is prime
* factors.Add(number);
* return factors;
*
* default:
* // There was an issue factorizing
* factors.Add(-number);
* return factors;
* }
*/
}
else
{
if (Program.primes[next] < 0)
{
// ran out of safe primes
next = Program.primes.Count;
continue;
}
}
BigInteger prime = Program.primes[next];
if (number % prime == 0)
{
factors.Add(prime);
number /= prime;
}
else
{
next += 1;
}
}
return(factors);
}
public static void Write(this BigFloat number, BinaryWriter writer)
{
MathExtras.WriteBigFloat(number, writer);
}