private ulong EvaluateInternal(ulong n, ulong x0, ulong xmax) { this.n = n; x0 = T1(x0 + 1); xmax = T1(xmax); if (x0 > xmax) { return(0); } var ymin = YFloor(xmax); var xmin = Math.Max(x0, Math.Min(T1(C1 * IntegerMath.CeilingRoot(2 * n, 3)), xmax)); #if DIAG Console.WriteLine("n = {0}, xmin = {1}, xmax = {2}", n, xmin, xmax); #endif var s = (ulong)0; var a2 = (ulong)1; var x2 = xmax; var y2 = ymin; var c2 = a2 * x2 + y2; while (true) { var a1 = a2 + 1; var x4 = YTan(a1); var y4 = YFloor(x4); var c4 = a1 * x4 + y4; var x5 = x4 + 1; var y5 = YFloor(x5); var c5 = a1 * x5 + y5; if (x4 <= xmin) { break; } s += Triangle(c4 - c2 - x0) - Triangle(c4 - c2 - x5) + Triangle(c5 - c2 - x5); if (threads == 0) { s += ProcessRegion(0, (ulong)(a1 * x2 + y2 - c5), (ulong)(a2 * x5 + y5 - c2), a1, 1, c5, a2, 1, c2); while (stack.Count > 0) { var r = stack.Pop(); s += ProcessRegion(0, r.w, r.h, r.a1, r.b1, r.c1, r.a2, r.b2, r.c2); } } else { Enqueue(new Region((ulong)(a1 * x2 + y2 - c5), (ulong)(a2 * x5 + y5 - c2), a1, 1, c5, a2, 1, c2)); } a2 = a1; x2 = x4; y2 = y4; c2 = c4; } s += (xmax - x0 + 1) * ymin + Triangle(xmax - x0); var rest = x2 - x0; s -= y2 * rest + a2 * Triangle(rest); xmanual = x2; return(s); }