void id_loop(Position& pos) {
- Stack stack[MAX_PLY_PLUS_6], *ss = stack+2; // To allow referencing (ss-2)
+ Stack stack[MAX_PLY+4], *ss = stack+2; // To allow referencing (ss-2) and (ss+2)
int depth;
Value bestValue, alpha, beta, delta;
multiPV = std::max(multiPV, skill.candidates_size());
// Iterative deepening loop until requested to stop or target depth reached
- while (++depth <= MAX_PLY && !Signals.stop && (!Limits.depth || depth <= Limits.depth))
+ while (++depth < MAX_PLY && !Signals.stop && (!Limits.depth || depth <= Limits.depth))
{
// Age out PV variability metric
BestMoveChanges *= 0.5;
moveCount = quietCount = 0;
bestValue = -VALUE_INFINITE;
- ss->currentMove = ss->ttMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
ss->ply = (ss-1)->ply + 1;
- (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
- (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
// Used to send selDepth info to GUI
if (PvNode && thisThread->maxPly < ss->ply)
if (!RootNode)
{
// Step 2. Check for aborted search and immediate draw
- if (Signals.stop || pos.is_draw() || ss->ply > MAX_PLY)
- return ss->ply > MAX_PLY && !inCheck ? evaluate(pos) : DrawValue[pos.side_to_move()];
+ if (Signals.stop || pos.is_draw() || ss->ply >= MAX_PLY)
+ return ss->ply >= MAX_PLY && !inCheck ? evaluate(pos) : DrawValue[pos.side_to_move()];
// Step 3. Mate distance pruning. Even if we mate at the next move our score
// would be at best mate_in(ss->ply+1), but if alpha is already bigger because
return alpha;
}
+ assert(0 <= ss->ply && ss->ply < MAX_PLY);
+
+ ss->currentMove = ss->ttMove = (ss+1)->excludedMove = bestMove = MOVE_NONE;
+ (ss+1)->skipNullMove = false; (ss+1)->reduction = DEPTH_ZERO;
+ (ss+2)->killers[0] = (ss+2)->killers[1] = MOVE_NONE;
+
// Step 4. Transposition table lookup
// We don't want the score of a partial search to overwrite a previous full search
// TT value, so we use a different position key in case of an excluded move.
ss->ply = (ss-1)->ply + 1;
// Check for an instant draw or if the maximum ply has been reached
- if (pos.is_draw() || ss->ply > MAX_PLY)
- return ss->ply > MAX_PLY && !InCheck ? evaluate(pos) : DrawValue[pos.side_to_move()];
+ if (pos.is_draw() || ss->ply >= MAX_PLY)
+ return ss->ply >= MAX_PLY && !InCheck ? evaluate(pos) : DrawValue[pos.side_to_move()];
+
+ assert(0 <= ss->ply && ss->ply < MAX_PLY);
// Decide whether or not to include checks: this fixes also the type of
// TT entry depth that we are going to use. Note that in qsearch we use
void RootMove::extract_pv_from_tt(Position& pos) {
- StateInfo state[MAX_PLY_PLUS_6], *st = state;
+ StateInfo state[MAX_PLY], *st = state;
const TTEntry* tte;
int ply = 1; // At root ply is 1...
Move m = pv[0]; // ...instead pv[] array starts from 0
void RootMove::insert_pv_in_tt(Position& pos) {
- StateInfo state[MAX_PLY_PLUS_6], *st = state;
+ StateInfo state[MAX_PLY], *st = state;
const TTEntry* tte;
int idx = 0; // Ply starts from 1, we need to start from 0
Threads.mutex.unlock();
- Stack stack[MAX_PLY_PLUS_6], *ss = stack+2; // To allow referencing (ss-2)
+ Stack stack[MAX_PLY+4], *ss = stack+2; // To allow referencing (ss-2) and (ss+2)
Position pos(*sp->pos, this);
std::memcpy(ss-2, sp->ss-2, 5 * sizeof(Stack));