- for (int pv = 0; pv <= 1; ++pv)
- for (int imp = 0; imp <= 1; ++imp)
- for (int d = 1; d < 64; ++d)
- for (int mc = 1; mc < 64; ++mc)
- {
- double r = K[pv][0] + log(d) * log(mc) / K[pv][1];
-
- if (r >= 1.5)
- Reductions[pv][imp][d][mc] = int(r) * ONE_PLY;
-
- // Increase reduction when eval is not improving
- if (!pv && !imp && Reductions[pv][imp][d][mc] >= 2 * ONE_PLY)
- Reductions[pv][imp][d][mc] += ONE_PLY;
- }
+ for (int imp = 0; imp <= 1; ++imp)
+ for (int d = 1; d < 64; ++d)
+ for (int mc = 1; mc < 64; ++mc)
+ {
+ double r = log(d) * log(mc) / 2;
+ if (r < 0.80)
+ continue;
+
+ Reductions[!PV][imp][d][mc] = int(std::round(r)) * ONE_PLY;
+ Reductions[PV][imp][d][mc] = std::max(Reductions[!PV][imp][d][mc] - ONE_PLY, DEPTH_ZERO);
+
+ // Increase reduction for non-PV nodes when eval is not improving
+ if (!imp && Reductions[!PV][imp][d][mc] >= 2 * ONE_PLY)
+ Reductions[!PV][imp][d][mc] += ONE_PLY;
+ }