private OmgNum _FermaFactorization(Dictionary <OmgNum, OmgNum> result, OmgNum num)
{
OmgNum factor = null;
if (OmgOp.DivMod(num, 2.ToOmgNum()).mod.IsZero())
{
factor = 2.ToOmgNum();
}
if (factor == null)
{
OmgNum a = OmgOp.Sqrt(num);
OmgNum aSq = OmgOp.Multiply(a, a);
bool isSquare = OmgOp.Equal(num, aSq);
if (isSquare)
{
factor = a;
}
a.Inc();
aSq = OmgOp.Multiply(a, a);
var s = OmgOp.Subtract(aSq, num);
while (factor == null)
{
var testSqrt = OmgOp.Sqrt(s);
if (OmgOp.Equal(s, OmgOp.Multiply(testSqrt, testSqrt)))
{
factor = (OmgOp.Equal(testSqrt, a)) ? OmgOp.Add(a, a) : OmgOp.Subtract(a, testSqrt);
break;
}
a.Inc();
aSq = OmgOp.Multiply(a, a);
s = OmgOp.Subtract(aSq, num);
}
}
if (factor == null || factor.IsOne())
{
return(num);
}
OmgNum pow = _FindPow(ref num, factor);
if (result.ContainsKey(factor))
{
result[factor] = OmgOp.Add(result[factor], pow);
}
else
{
result[factor] = pow;
}
return(num);
}
private OmgNum _SelectExponent(OmgNum carmN)
{
OmgNum candidate = ((1 << 16) + 1).ToOmgNum();
OmgNum gcd = OmgOp.Gcd(candidate, carmN);
while (!gcd.IsOne())
{
gcd = OmgOp.Gcd(candidate.Inc(), carmN);
}
gcd.Release();
return(candidate);
}
public OmgNum FindFactor(OmgNum n, int maxIterations = -1)
{
m_iterations = 0;
m_current = n;
OmgNum x = OmgOp.Random(1.ToOmgNum(), OmgOp.Subtract(n, 2.ToOmgNum()));
OmgNum y = 1.ToOmgNum();
OmgNum i = 0.ToOmgNum();
OmgNum stage = 2.ToOmgNum();
OmgNum sub = OmgOp.Subtract(x, y).MakeAbs();
OmgNum gcd = OmgOp.Gcd(n, sub);
sub.Release();
while (gcd.IsOne())
{
if (maxIterations >= 0 && m_iterations++ > maxIterations)
{
return(null);
}
if (OmgOp.Equal(i, stage))
{
y.Release();
y = new OmgNum(x);
stage.MultByTwo();
}
OmgNum xSquare = OmgOp.Multiply(x, x).Inc();
x.Release();
x = OmgOp.Mod(xSquare, n);
xSquare.Release();
i.Inc();
sub = OmgOp.Subtract(x, y).MakeAbs();
gcd.Release();
gcd = OmgOp.Gcd(n, sub);
sub.Release();
}
return(gcd);
}
private OmgNum _FindFactorsWithPollard(Dictionary <OmgNum, OmgNum> result, OmgNum num)
{
num = num.Copy();
while (!num.IsOne())
{
OmgNum factor = m_polard.FindFactor(num, maxIterations: 100000);
if (factor == null || factor.IsOne() || OmgOp.Equal(factor, num))
{
return(num);
}
OmgNum pow = _FindPow(ref num, factor);
result[factor] = pow;
}
return(num);
}
public Dictionary <OmgNum, OmgNum> Factorize(OmgNum num)
{
var initNum = num.Copy();
var result = new Dictionary <OmgNum, OmgNum>();
if (_IsSmallPrime(result, num))
{
return(result);
}
num = _FindFactorsWithPollard(result, num);
num = _FermaFactorization(result, num);
if (!num.IsOne())
{
result[num] = 1.ToOmgNum();
}
if (result.Count == 1 && result.TryGetValue(initNum, out var power) && power.IsOne())
{
return(result);
}
var nonPrimeFactors = new Stack <OmgNum>(result.Keys);
while (nonPrimeFactors.Count > 0)
{
var factor = nonPrimeFactors.Pop();
if (result[factor].IsZero())
{
result.Remove(factor);
continue;
}
var primeFactors = Factorize(factor);
if (primeFactors.Count == 1 && primeFactors.Values.First().IsOne())
{
continue;
}
var topPower = result[factor];
result.Remove(factor);
foreach (var primeFactor in primeFactors)
{
var pow = OmgOp.Multiply(topPower, primeFactor.Value);
if (result.ContainsKey(primeFactor.Key))
{
result[primeFactor.Key] = OmgOp.Add(result[primeFactor.Key], pow);
}
else
{
result[primeFactor.Key] = pow;
}
}
}
var keys = new List <OmgNum>(result.Keys);
foreach (var key in keys)
{
if (result[key].IsZero())
{
result.Remove(key);
}
}
return(result);
}
