internal void FindAllFactors( Integer FindFromNotChanged )
{
// ShowStats(); // So far.
OriginalFindFrom.Copy( FindFromNotChanged );
FindFrom.Copy( FindFromNotChanged );
NumbersTested++;
ClearFactorsArray();
Integer OneFactor;
OneFactorRec Rec;
// while( not forever )
for( int Count = 0; Count < 1000; Count++ )
{
if( Worker.CancellationPending )
return;
uint SmallPrime = IntMath.IsDivisibleBySmallPrime( FindFrom );
if( SmallPrime == 0 )
break; // No more small primes.
// Worker.ReportProgress( 0, "Found a small prime factor: " + SmallPrime.ToString() );
AddToStats( SmallPrime );
OneFactor = new Integer();
OneFactor.SetFromULong( SmallPrime );
Rec = new OneFactorRec();
Rec.Factor = OneFactor;
Rec.IsDefinitelyAPrime = true;
AddFactorRec( Rec );
if( FindFrom.IsULong())
{
ulong CheckLast = FindFrom.GetAsULong();
if( CheckLast == SmallPrime )
{
Worker.ReportProgress( 0, "It only had small prime factors." );
VerifyFactors();
return; // It had only small prime factors.
}
}
IntMath.Divide( FindFrom, OneFactor, Quotient, Remainder );
if( !Remainder.IsZero())
throw( new Exception( "Bug in FindAllFactors. Remainder is not zero." ));
FindFrom.Copy( Quotient );
if( FindFrom.IsOne())
throw( new Exception( "Bug in FindAllFactors. This was already checked for 1." ));
}
// Worker.ReportProgress( 0, "No more small primes." );
if( IsFermatPrimeAdded( FindFrom ))
{
VerifyFactors();
return;
}
// while( not forever )
for( int Count = 0; Count < 1000; Count++ )
{
if( Worker.CancellationPending )
return;
// If FindFrom is a ulong then this will go up to the square root of
// FindFrom and return zero if it doesn't find it there. So it can't
// go up to the whole value of FindFrom.
uint SmallFactor = NumberIsDivisibleByUInt( FindFrom );
if( SmallFactor == 0 )
break;
// This is necessarily a prime because it was the smallest one found.
AddToStats( SmallFactor );
// Worker.ReportProgress( 0, "Found a small factor: " + SmallFactor.ToString( "N0" ));
OneFactor = new Integer();
OneFactor.SetFromULong( SmallFactor );
Rec = new OneFactorRec();
Rec.Factor = OneFactor;
Rec.IsDefinitelyAPrime = true; // The smallest factor. It is necessarily a prime.
AddFactorRec( Rec );
IntMath.Divide( FindFrom, OneFactor, Quotient, Remainder );
if( !Remainder.IsZero())
throw( new Exception( "Bug in FindAllFactors. Remainder is not zero. Second part." ));
if( Quotient.IsOne())
throw( new Exception( "This can't happen here. It can't go that high." ));
FindFrom.Copy( Quotient );
if( IsFermatPrimeAdded( FindFrom ))
{
VerifyFactors();
return;
}
}
if( IsFermatPrimeAdded( FindFrom ))
{
VerifyFactors();
return;
}
// If it got this far then it's definitely composite or definitely
// small enough to factor.
Integer P = new Integer();
Integer Q = new Integer();
bool TestedAllTheWay = FindTwoFactorsWithFermat( FindFrom, P, Q, 0 );
if( !P.IsZero())
{
// Q is necessarily prime because it's bigger than the square root.
// But P is not necessarily prime.
// P is the smaller one, so add it first.
if( IsFermatPrimeAdded( P ))
{
Worker.ReportProgress( 0, "P from Fermat method was probably a prime." );
}
else
{
OneFactor = new Integer();
OneFactor.Copy( P );
Rec = new OneFactorRec();
Rec.Factor = OneFactor;
Rec.IsDefinitelyNotAPrime = true;
AddFactorRec( Rec );
}
Worker.ReportProgress( 0, "Q is necessarily prime." );
OneFactor = new Integer();
OneFactor.Copy( Q );
Rec = new OneFactorRec();
Rec.Factor = OneFactor;
Rec.IsDefinitelyAPrime = true;
AddFactorRec( Rec );
}
else
{
// Didn't find any with Fermat.
OneFactor = new Integer();
OneFactor.Copy( FindFrom );
Rec = new OneFactorRec();
Rec.Factor = OneFactor;
if( TestedAllTheWay )
Rec.IsDefinitelyAPrime = true;
else
Rec.IsDefinitelyNotAPrime = true;
AddFactorRec( Rec );
}
Worker.ReportProgress( 0, "That's all it could find." );
VerifyFactors();
}
private void AddFactorRec( OneFactorRec Rec )
{
// if( Rec == null )
// return false;
FactorsArray[FactorsArrayLast] = Rec;
SortIndexArray[FactorsArrayLast] = FactorsArrayLast;
FactorsArrayLast++;
if( FactorsArrayLast >= FactorsArray.Length )
{
try
{
Array.Resize( ref FactorsArray, FactorsArray.Length + 16 );
Array.Resize( ref SortIndexArray, FactorsArray.Length );
}
catch( Exception Except )
{
throw( new Exception( "Couldn't resize the arrays for FindFactors.cs. " + Except.Message ));
}
}
}
private bool IsFermatPrimeAdded( Integer FindFrom )
{
if( FindFrom.IsULong())
{
// The biggest size that NumberIsDivisibleByUInt() will check to
// see if it has primes for sure.
if( FindFrom.GetAsULong() < (223092870UL * 223092870UL))
return false; // Factor this.
}
int HowManyTimes = 20; // How many primes it will be checked with.
if( !IntMath.IsFermatPrime( FindFrom, HowManyTimes ))
return false;
Integer OneFactor = new Integer();
OneFactor.Copy( FindFrom );
OneFactorRec Rec = new OneFactorRec();
Rec.Factor = OneFactor;
// Neither one of these is set to true here because it's probably
// a prime, but not definitely.
// Rec.IsDefinitelyAPrime = false;
// Rec.IsDefinitelyNotAPrime = false;
AddFactorRec( Rec );
Worker.ReportProgress( 0, "Fermat thinks this one is a prime." );
return true; // It's a Fermat prime and it was added.
}
internal void FindSmallPrimeFactorsOnly( Integer FindFromNotChanged )
{
OriginalFindFrom.Copy( FindFromNotChanged );
FindFrom.Copy( FindFromNotChanged );
ClearFactorsArray();
Integer OneFactor;
OneFactorRec Rec;
// while( not forever )
for( int Count = 0; Count < 1000; Count++ )
{
if( Worker.CancellationPending )
return;
uint SmallPrime = IntMath.IsDivisibleBySmallPrime( FindFrom );
if( SmallPrime == 0 )
break; // No more small primes.
// Worker.ReportProgress( 0, "Found a small prime factor: " + SmallPrime.ToString() );
OneFactor = new Integer();
OneFactor.SetFromULong( SmallPrime );
Rec = new OneFactorRec();
Rec.Factor = OneFactor;
Rec.IsDefinitelyAPrime = true;
AddFactorRec( Rec );
if( FindFrom.IsULong())
{
ulong CheckLast = FindFrom.GetAsULong();
if( CheckLast == SmallPrime )
{
// Worker.ReportProgress( 0, "It only had small prime factors." );
VerifyFactors();
return; // It had only small prime factors.
}
}
IntMath.Divide( FindFrom, OneFactor, Quotient, Remainder );
if( !Remainder.IsZero())
throw( new Exception( "Bug in FindSmallPrimeFactorsOnly(). Remainder is not zero." ));
FindFrom.Copy( Quotient );
if( FindFrom.IsOne())
throw( new Exception( "Bug in FindSmallPrimeFactorsOnly(). This was already checked for 1." ));
}
// Worker.ReportProgress( 0, "One factor was not a small prime." );
OneFactor = new Integer();
OneFactor.Copy( FindFrom );
Rec = new OneFactorRec();
Rec.Factor = OneFactor;
AddFactorRec( Rec );
// Worker.ReportProgress( 0, "No more small primes." );
}