public void TestFlip()
{
BetterBitArray bitArray = new BetterBitArray(100000);
for (UInt32 i = 0; i < bitArray.bitLength; i++)
{
Assert.IsFalse(bitArray.Get(i));
}
for (UInt32 i = 0; i < bitArray.bitLength; i++)
{
bitArray.Flip(i);
}
for (UInt32 i = 0; i < bitArray.bitLength; i++)
{
Assert.IsTrue(bitArray.Get(i));
}
for (UInt32 i = 0; i < bitArray.bitLength; i++)
{
bitArray.Flip(i);
}
for (UInt32 i = 0; i < bitArray.bitLength; i++)
{
Assert.IsFalse(bitArray.Get(i));
}
}
public static void PerformanceTestBitArrays(Int32 length)
{
long before;
System.Collections.BitArray bitArray = new System.Collections.BitArray(length);
BetterBitArray betterBitArray = new BetterBitArray((UInt32)length);
before = Stopwatch.GetTimestamp();
for (int i = 0; i < 10000; i++)
{
bitArray.SetAll(false);
//bitArray.Set(0, true);
}
Console.WriteLine((Stopwatch.GetTimestamp() - before).StopwatchTicksAsInt64Milliseconds());
PrintGC("BitArray");
before = Stopwatch.GetTimestamp();
for (int i = 0; i < 10000; i++)
{
betterBitArray.SetAll(false);
//betterBitArray.Assert(0);
}
Console.WriteLine((Stopwatch.GetTimestamp() - before).StopwatchTicksAsInt64Milliseconds());
PrintGC("BetterBitArray");
}
//
// On an HP Z600, It takes about 38 seconds to generate
// the first 150 million primes (about 4 million primes per second)
//
public static UInt32[] GeneratePrimes(UInt32 max, out UInt32 outPrimeCount)
{
if (max == UInt32.MaxValue)
{
throw new ArgumentOutOfRangeException("max", "max cannot be UInt32.MaxValue");
}
UInt32[] primes = new UInt32[PrimeCount.UpperBound(max)];
UInt32 primeCount;
UInt32 maxSquareRoot = (UInt32)Math.Sqrt(max);
BetterBitArray isComposite = new BetterBitArray((max + 1) >> 1);
primes[0] = 2;
primes[1] = 3;
primeCount = 2;
UInt32 candidatePrime;
UInt32 incrementAmount = 0;
for (candidatePrime = 5; candidatePrime <= maxSquareRoot; candidatePrime += incrementAmount)
{
if (!isComposite.Get(candidatePrime >> 1))
{
//
// Mark all multiples of this prime as composites
//
UInt32 candidatePrimeDoubled = 2 * candidatePrime;
for (UInt32 j = candidatePrime * candidatePrime; j <= max; j += candidatePrimeDoubled)
{
isComposite.Assert(j >> 1);
}
//
// Add to the primes
//
primes[primeCount++] = candidatePrime;
}
incrementAmount = (incrementAmount == 2) ? 4U : 2U;
}
// Add the rest of the primes
for (; candidatePrime <= max; candidatePrime += incrementAmount)
{
if (!isComposite.Get(candidatePrime >> 1))
{
primes[primeCount++] = candidatePrime;
}
incrementAmount = (incrementAmount == 2) ? 4U : 2U;
}
outPrimeCount = primeCount;
return(primes);
}
public void XorEquals(BetterBitArray other)
{
if (this.bitLength != other.bitLength)
{
throw new ArgumentException(String.Format("Given bit array is {0} bits but this bit array is {1}", other.bitLength, this.bitLength));
}
UInt32 thisArrayLength = (UInt32)this.array.Length;
for (UInt32 i = 0; i < thisArrayLength; i++)
{
this.array[i] ^= other.array[i];
}
}
public static UInt32[] GeneratePrimes(UInt32 max, out UInt32 outPrimeCount)
{
if (max < 5)
{
throw new ArgumentOutOfRangeException("max", "max can't be too small");
}
if (max == UInt32.MaxValue)
{
throw new ArgumentOutOfRangeException("max", "max cannot be UInt32.MaxValue");
}
UInt32[] primes = new UInt32[PrimeCount.UpperBound(max)];
UInt32 primeCount;
UInt32 maxSquareRoot = (UInt32)Math.Sqrt(max);
BetterBitArray isPrime = new BetterBitArray(max + 1);
// put in candidate primes
for (UInt32 i = 1; i <= maxSquareRoot; i++)
{
for (UInt32 j = 1; j <= maxSquareRoot; j++)
{
UInt32 n;
n = 4 * i + j;
//if (n > max) throw new InvalidOperationException();
if (n <= max) // Should always be true for large enough max (maybe take this out0
{
UInt32 nMod12 = n % 12;
if (nMod12 == 1 || nMod12 == 5)
{
isPrime.Flip(n);
}
}
n = 3 * i + j;
//if (n > max) throw new InvalidOperationException();
if (n <= max) // Should always be true for large enough max (maybe take this out0
{
UInt32 nMod12 = n % 12;
if (nMod12 == 7)
{
isPrime.Flip(n);
}
}
if (i > j)
{
n = 3 * i - j;
//if (n > max) throw new InvalidOperationException();
if (n <= max) // Should always be true for large enough max (maybe take this out0
{
UInt32 nMod12 = n % 12;
if (nMod12 == 11)
{
isPrime.Flip(n);
}
}
}
}
}
primes[0] = 2;
primes[1] = 3;
primeCount = 2;
UInt32 candidatePrime;
for (candidatePrime = 5; candidatePrime <= maxSquareRoot; candidatePrime += 2)
{
if (isPrime.Get(candidatePrime))
{
//
// Mark all multiples of its square as composite
//
//
UInt32 candidatePrimeSquared = candidatePrime * candidatePrime;
//UInt32 candidatePrimeSquaredThenDoubled = iSquared * 2;
for (UInt32 j = candidatePrimeSquared; j <= max; j += candidatePrimeSquared)
{
isPrime.Deassert(j);
}
//
// Add to the primes
//
primes[primeCount++] = candidatePrime;
}
}
// Add the rest of the primes
for (; candidatePrime <= max; candidatePrime += 2)
{
if (isPrime.Get(candidatePrime))
{
primes[primeCount++] = candidatePrime;
}
}
outPrimeCount = primeCount;
return(primes);
}
public Enumerator(BetterBitArray bitarray)
{
this.bitarray = bitarray;
this.bitIndex = UInt32.MaxValue;
}
