public BigInteger T3Slow(BigInteger n)
{
var sum = (BigInteger)0;
var root3 = IntegerMath.FloorRoot(n, 3);
if (threads == 0)
{
sum += T3Worker(n, root3, 0, 1);
}
else
{
var tasks = new Task[threads];
for (var i = 0; i < threads; i++)
{
var thread = i;
tasks[i] = new Task(() =>
{
var s = T3Worker(n, root3, thread, threads);
lock (this)
sum += s;
});
tasks[i].Start();
}
Task.WaitAll(tasks);
}
return(3 * sum + IntegerMath.Power(T1(root3), 3));
}
public static Rational CeilingRoot(Rational a, Rational b)
{
var c = FloorRoot(a, b);
if (IntegerMath.Power(a, c) != c)
{
++c;
}
return(c);
}
private BigInteger T3Worker(BigInteger n, BigInteger root3, int worker, int workers)
{
var s = (BigInteger)0;
for (var z = (BigInteger)1 + 2 * worker; z <= root3; z += 2 * workers)
{
var nz = n / z;
var sqrtnz = IntegerMath.FloorSquareRoot(nz);
var t = hyperbolicSum[worker].Evaluate(nz, (long)z + 2, (long)sqrtnz);
s += 2 * t - IntegerMath.Power(T1(sqrtnz), 2) + T1(nz / z);
}
return(s);
}
public BigInteger F3(BigInteger n)
{
//Console.WriteLine("F3({0})", n);
var s = (BigInteger)0;
var dmax = IntegerMath.FloorRoot(n, 3);
for (var d = 1; d <= dmax; d += 2)
{
var md = mobius[d];
if (md == 0)
{
continue;
}
var term = T3(n / IntegerMath.Power((BigInteger)d, 3));
s += md * term;
}
Debug.Assert((s - 1) % 3 == 0);
return((s - 1) / 3);
}
public override Rational Power(Rational a, Rational b)
{
return(IntegerMath.Power(a, b));
}
public override uint Power(uint a, uint b)
{
return(IntegerMath.Power(a, b));
}
public override Int128 Power(Int128 a, Int128 b)
{
return(IntegerMath.Power(a, b));
}
public override ulong Power(ulong a, ulong b)
{
return(IntegerMath.Power(a, b));
}
public override BigInteger Power(BigInteger a, BigInteger b)
{
return(IntegerMath.Power(a, b));
}
