// Step 14. Reduced search
// Reduction lookup tables (initialized at startup) and their getter functions
- int8_t PVReductionMatrix[64][64]; // [depth][moveNumber]
- int8_t NonPVReductionMatrix[64][64]; // [depth][moveNumber]
+ int8_t PVReductionMatrix[8][64][64]; // [depth][moveNumber]
+ int8_t NonPVReductionMatrix[8][64][64]; // [depth][moveNumber]
- inline Depth pv_reduction(Depth d, int mn) { return (Depth) PVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; }
- inline Depth nonpv_reduction(Depth d, int mn) { return (Depth) NonPVReductionMatrix[Min(d / 2, 63)][Min(mn, 63)]; }
+ inline Depth pv_reduction(Depth d, int mn) { return (Depth) PVReductionMatrix[0][Min(d / 2, 63)][Min(mn, 63)]; }
+ inline Depth nonpv_reduction(Depth d, int mn) { return (Depth) NonPVReductionMatrix[0][Min(d / 2, 63)][Min(mn, 63)]; }
// Common adjustments
{
TM.set_active_threads(newActiveThreads);
init_eval(TM.active_threads());
- // HACK: init_eval() destroys the static castleRightsMask[] array in the
- // Position class. The below line repairs the damage.
- Position p(pos.to_fen());
- assert(pos.is_ok());
}
// Wake up sleeping threads
return !Quit;
}
+// init_reduction_tables()
-/// init_search() is called during startup. It initializes various lookup tables
-
-void init_search() {
+void init_reduction_tables(int8_t pvTable[64][64], int8_t nonPvTable[64][64], int pvInhib, int nonPvInhib)
+{
+ double pvBase = 1.001 - log(3.0) * log(16.0) / pvInhib;
+ double nonPvBase = 1.001 - log(3.0) * log(4.0) / nonPvInhib;
- // Init our reduction lookup tables
+ // Init reduction lookup tables
for (int i = 1; i < 64; i++) // i == depth (OnePly = 1)
for (int j = 1; j < 64; j++) // j == moveNumber
{
- double pvRed = 0.5 + log(double(i)) * log(double(j)) / 6.0;
- double nonPVRed = 0.5 + log(double(i)) * log(double(j)) / 3.0;
- PVReductionMatrix[i][j] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(OnePly)) : 0);
- NonPVReductionMatrix[i][j] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(OnePly)) : 0);
+ double pvRed = pvBase + log(double(i)) * log(double(j)) / pvInhib;
+ double nonPVRed = nonPvBase + log(double(i)) * log(double(j)) / nonPvInhib;
+
+ pvTable[i][j] = (int8_t) ( pvRed >= 1.0 ? floor( pvRed * int(OnePly)) : 0);
+ nonPvTable[i][j] = (int8_t) (nonPVRed >= 1.0 ? floor(nonPVRed * int(OnePly)) : 0);
}
+}
+
+// init_search() is called during startup. It initializes various lookup tables
+
+void init_search() {
+
+ for (int i = 0; i < 8; i++)
+ init_reduction_tables(PVReductionMatrix[i], NonPVReductionMatrix[i], 4.0 * pow(1.3, i), 2.0 * pow(1.3, i));
// Init futility margins array
for (int i = 0; i < 16; i++) // i == depth (OnePly = 2)
if (nullValue >= beta)
{
+ // Do not return unproven mate scores
+ if (nullValue >= value_mate_in(PLY_MAX))
+ nullValue = beta;
+
if (depth < 6 * OnePly)
- return beta;
+ return nullValue;
// Do zugzwang verification search
Value v = search(pos, ss, beta, depth-5*OnePly, ply, false, threadID);
if (v >= beta)
- return beta;
+ return nullValue;
} else {
// The null move failed low, which means that we may be faced with
// some kind of threat. If the previous move was reduced, check if