/**
* The Factor Base size B is given by (e ^ (sqrt(r))) ^ (sqrt(2)/4)
*
* Where r = ln(n) * ln(ln(n))
*
* Even for numbers in the millions of trillions, r ends up being very small, so in order to do exact math we assume r can fit inside a double.
*
* Since we must have an integer number of factor bases, we take the floor of B.
**/
public static int getFactorBaseSize(BigInteger number_to_factor)
{
double r = BigInteger.Log(number_to_factor) * (BigInteger.Log(BigIntegerWrapper.Log(number_to_factor)));
double exact_value = Math.Pow(Math.Pow(Math.E, Math.Sqrt(r)), (Math.Sqrt(2) / 4));
return((int)Math.Floor(exact_value));
}
public static int SieveofSundaramSerial(BigInteger to_factor)
{
if (BigIntegerWrapper.SqRt(to_factor) < int.MaxValue - 1)
{
int BAsize = (int)BigIntegerWrapper.SqRt(to_factor);
int k = BAsize / 2;
BitArray tracker = new BitArray(BAsize);
/* SET ALL TO PRIME STATUS */
tracker.SetAll(true);
int maxVal = 0;
int denominator = 0;
Stopwatch sundaram_serial = new Stopwatch();
sundaram_serial.Start();
for (int i = 1; i < k; i++)
{
denominator = (i << 1) + 1;
maxVal = (k - i) / denominator;
for (int j = i; j <= maxVal; j++)
{
tracker[i + j * denominator] = false;
}
}
sundaram_serial.Stop();
Stopwatch serielsearch = new Stopwatch();
serielsearch.Start();
int dummy = 0;
for (int i = 1; i < k; i++)
{
if (tracker[i])
{
dummy = (i << 1) + 1; // dummy contains prime number.The code is here not ignore the prime number calcuation part.
if (to_factor % dummy == 0)
{
break;
}
}
}
serielsearch.Stop();
Console.WriteLine("search runtime: " + serielsearch.ElapsedMilliseconds + "ms.");
Console.WriteLine("Serial Sieve of Sundaram Runtime: " + sundaram_serial.ElapsedMilliseconds + "ms.");
return(dummy);
}
else
{
Console.WriteLine("Too big to factor with Sieve of Sundaram. ");
return(-1);
}
}
public static BigInteger computeQX(BigInteger x, BigInteger n)
{
return(BigInteger.Pow((x + BigIntegerWrapper.SqRt(n)), 2) % n);
}
public static int SieveofSundaramParallel(BigInteger to_factor)
{
if (BigIntegerWrapper.SqRt(to_factor) < int.MaxValue - 1)
{
int BAsize = (int)BigIntegerWrapper.SqRt(to_factor);
int k = BAsize / 2;
BitArray tracker = new BitArray(BAsize);
/* SET ALL TO PRIME STATUS */
tracker.SetAll(true);
int maxVal = 0;
int denominator = 0;
Stopwatch sundaram_parallel = new Stopwatch();
sundaram_parallel.Start();
for (int i = 1; i < k; i++)
{
denominator = (i << 1) + 1;
maxVal = (k - i) / denominator;
/*Parallel.For(i, maxVal, new ParallelOptions { MaxDegreeOfParallelism = 2 }, (j, state) =>
* {
* tracker[i + j * denominator] = false;
* });*/
for (int j = i; j <= maxVal; j++)
{
tracker[i + j * denominator] = false;
}
}
sundaram_parallel.Stop();
Stopwatch parallelSearch = new Stopwatch();
parallelSearch.Start();
int dummy = 0;
int final = 0;
Parallel.For(1, k, new ParallelOptions {
MaxDegreeOfParallelism = 4
}, (i, state) =>
{
if (tracker[i])
{
dummy = (i << 1) + 1; // dummy contains prime number.The code is here not ignore the prime number calcuation part.
if (to_factor % dummy == 0)
{
final = dummy;
state.Break();
}
}
});
parallelSearch.Stop();
Console.WriteLine("search runtime: " + parallelSearch.ElapsedMilliseconds + "ms.");
Console.WriteLine("Parallel Sieve of Sundaram Runtime: " + sundaram_parallel.ElapsedMilliseconds + "ms.");
return(final);
}
else
{
Console.WriteLine("Too big to factor with Sieve of Sundaram. ");
return(-1);
}
}
public BigInteger[] getFactorsSerial()
{
BigInteger p = 1997333137;
BigInteger q = 2106945901;
BigInteger integer_to_factor = p * q;
Console.WriteLine("p value: " + p);
Console.WriteLine("q value: " + q);
BigInteger[] bruteforce_Serial = LeedamKeyson.factorModulusSerial(integer_to_factor);
Console.WriteLine("brute force serial p value: " + bruteforce_Serial[0]);
Console.WriteLine("brute force serial q value: " + bruteforce_Serial[1]);
BigInteger[] bruteforce_Parallel = LeedamKeyson.factorModulusParallel(integer_to_factor);
Console.WriteLine("brute force parallel p value: " + bruteforce_Parallel[0]);
//Console.WriteLine("brute force parallel q value" + bruteforce_Parallel[1]);
int factor_serial = QuadraticSieveFunctions.SieveofSundaramSerial(integer_to_factor);
Console.WriteLine("Serial returns the p value: " + factor_serial);
Console.WriteLine("Serial returns the q value: " + (integer_to_factor / factor_serial));
int factor_parallel = QuadraticSieveFunctions.SieveofSundaramParallel(integer_to_factor);
Console.WriteLine("Parallel returns the p value: " + factor_parallel);
Console.WriteLine("Parallel returns the q value: " + (integer_to_factor / factor_parallel));
int factor_base_size = QuadraticSieveFunctions.getFactorBaseSize(integer_to_factor);
factor_base_size = (int)BigIntegerWrapper.SqRt(integer_to_factor);
BigInteger sieve_interval_upper = QuadraticSieveFunctions.getSieveInterval(factor_base_size);
int[] factor_base = QuadraticSieveFunctions.SieveOfErastosthenesSerial(factor_base_size);
factor_base = new int[] { 0 };
factor_base = QuadraticSieveFunctions.SieveOfErastosthenesParallel(factor_base_size);
int[] quadratic_residues = QuadraticSieveFunctions.getResiduesSerial(factor_base, integer_to_factor);
BigInteger sieve_interval = QuadraticSieveFunctions.getSieveInterval(factor_base_size);
BigInteger sieve_interval_start = BigIntegerWrapper.SqRt(integer_to_factor);
LinkedList <BigInteger[]> smooth_numbers = QuadraticSieveFunctions.SmoothNumberSieveSerial(integer_to_factor, quadratic_residues, sieve_interval_start, sieve_interval_start + sieve_interval);
//int k = 100000000;
//QuadraticSieveFunctions.getFactorBaseSize(integer_to_factor);
//int test_factor_base_size = QuadraticSieveFunctions.getFactorBaseSize(k);
int result = factorSerial(factor_base, integer_to_factor);
int result2 = factorParallel(factor_base, integer_to_factor);
//int[] factor_base_parallel_improved = QuadraticSieveFunctions.SieveOfErastosthenesParallelImproved(2 * k);
//int[] factor_base_parallel = QuadraticSieveFunctions.SieveOfErastosthenesParallel(2*k);
return(new BigInteger[] { result, (int)(sieve_interval_upper / result) });
}
public BigInteger BigRoot(BigInteger k, BigInteger integer_to_factor)
{
return(BigInteger.Pow((k + BigIntegerWrapper.SqRt(integer_to_factor)), 2) % integer_to_factor);
}
