public MertensFunctionWheel(int threads)
{
this.threads = threads;
wheelSubtotal = new int[wheelSize];
wheelInclude = new bool[wheelSize >> 1];
wheelNext = new byte[wheelSize >> 1];
wheelPrev = new byte[wheelSize >> 1];
var total = 0;
for (var i = 0; i < wheelSize; i++)
{
var include = IntegerMath.GreatestCommonDivisor(i, wheelSize) == 1;
if (include)
{
++total;
}
wheelSubtotal[i] = total;
wheelInclude[i >> 1] = include;
}
Debug.Assert(total == wheelCount);
var next = 0;
for (var i = (wheelSize >> 1) - 1; i >= 0; i--)
{
next += 2;
wheelNext[i] = (byte)next;
if (wheelInclude[i])
{
next = 0;
}
}
var prev = 0;
for (var i = 0; i < (wheelSize >> 1); i++)
{
prev += 2;
wheelPrev[i] = (byte)prev;
if (wheelInclude[i])
{
prev = 0;
}
}
#if DEBUG
for (var i = 1; i < wheelSize; i += 2)
{
var skip = wheelNext[i >> 1];
for (var j = 2; j < skip; j += 2)
{
if (wheelInclude[((i + j) % wheelSize) >> 1])
{
Debugger.Break();
}
}
if (!wheelInclude[((i + skip) % wheelSize) >> 1])
{
Debugger.Break();
}
}
for (var i = 1; i < wheelSize; i += 2)
{
var skip = wheelPrev[i >> 1];
for (var j = 2; j < skip; j += 2)
{
if (wheelInclude[((i - j + wheelSize) % wheelSize) >> 1])
{
Debugger.Break();
}
}
if (!wheelInclude[((i - skip + wheelSize) % wheelSize) >> 1])
{
Debugger.Break();
}
}
#endif
wheelFactors = IntegerMath.Factors(wheelSize).ToArray();
wheelMobius = wheelFactors.Select(factor => IntegerMath.Mobius(factor)).ToArray();
}
