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https://github.com/sockspls/badfish
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Retire probe_dtz() from Tablebases
It is not needed in SF.
This commit is contained in:
Marco Costalba
parent
7aeef7285f
commit
39e4398133
2 changed files with 236 additions and 235 deletions
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@ -505,7 +505,7 @@ public:
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// Given a position, produce a 64-bit material signature key. If the engine
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// supports such a key, it should equal the engine's key.
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Key get_key(Position& pos, bool mirror)
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Key get_key(const Position& pos, bool mirror)
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{
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Key key = 0;
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@ -1520,7 +1520,7 @@ WDLScore probe_wdl_table(Position& pos, int* success)
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}
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}
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int probe_dtz_table(Position& pos, int wdl, int *success)
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int probe_dtz_table(const Position& pos, int wdl, int *success)
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{
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uint64_t idx;
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int i, res;
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@ -1727,6 +1727,238 @@ WDLScore probe_ab(Position& pos, WDLScore alpha, WDLScore beta, int *success)
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}
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}
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int probe_dtz(Position& pos, int *success);
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// This routine treats a position with en passant captures as one without.
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int probe_dtz_no_ep(Position& pos, int *success)
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{
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int dtz;
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WDLScore wdl = probe_ab(pos, WDLHardLoss, WDLHardWin, success);
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if (*success == 0) return 0;
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if (wdl == WDLDraw) return 0;
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if (*success == 2)
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return wdl == WDLHardWin ? 1 : 101;
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ExtMove stack[MAX_MOVES];
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ExtMove *moves, *end = NULL;
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StateInfo st;
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CheckInfo ci(pos);
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if (wdl > 0) {
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// Generate at least all legal non-capturing pawn moves
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// including non-capturing promotions.
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if (!pos.checkers())
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end = generate<NON_EVASIONS>(pos, stack);
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else
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end = generate<EVASIONS>(pos, stack);
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for (moves = stack; moves < end; ++moves) {
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Move move = moves->move;
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if ( type_of(pos.moved_piece(move)) != PAWN
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|| pos.capture(move)
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|| !pos.legal(move, ci.pinned))
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continue;
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pos.do_move(move, st, pos.gives_check(move, ci));
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WDLScore v = -probe_ab(pos, WDLHardLoss, -wdl + WDLSoftWin, success);
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pos.undo_move(move);
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if (*success == 0) return 0;
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if (v == wdl)
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return v == WDLHardWin ? 1 : 101;
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}
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}
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dtz = 1 + probe_dtz_table(pos, wdl, success);
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if (*success >= 0) {
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if (wdl & 1) dtz += 100;
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return wdl >= 0 ? dtz : -dtz;
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}
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if (wdl > 0) {
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int best = 0xffff;
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for (moves = stack; moves < end; ++moves) {
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Move move = moves->move;
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if (pos.capture(move) || type_of(pos.moved_piece(move)) == PAWN
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|| !pos.legal(move, ci.pinned))
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continue;
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pos.do_move(move, st, pos.gives_check(move, ci));
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int v = -probe_dtz(pos, success);
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pos.undo_move(move);
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if (*success == 0)
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return 0;
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if (v > 0 && v + 1 < best)
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best = v + 1;
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}
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return best;
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} else {
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int best = -1;
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if (!pos.checkers())
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end = generate<NON_EVASIONS>(pos, stack);
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else
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end = generate<EVASIONS>(pos, stack);
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for (moves = stack; moves < end; ++moves) {
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int v;
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Move move = moves->move;
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if (!pos.legal(move, ci.pinned))
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continue;
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pos.do_move(move, st, pos.gives_check(move, ci));
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if (st.rule50 == 0) {
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if (wdl == -2) v = -1;
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else {
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v = probe_ab(pos, WDLSoftWin, WDLHardWin, success);
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v = (v == 2) ? 0 : -101;
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}
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} else {
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v = -probe_dtz(pos, success) - 1;
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}
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pos.undo_move(move);
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if (*success == 0)
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return 0;
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if (v < best)
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best = v;
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}
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return best;
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}
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}
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// Probe the DTZ table for a particular position.
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// If *success != 0, the probe was successful.
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// The return value is from the point of view of the side to move:
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// n < -100 : loss, but draw under 50-move rule
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// -100 <= n < -1 : loss in n ply (assuming 50-move counter == 0)
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// 0 : draw
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// 1 < n <= 100 : win in n ply (assuming 50-move counter == 0)
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// 100 < n : win, but draw under 50-move rule
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//
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// The return value n can be off by 1: a return value -n can mean a loss
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// in n+1 ply and a return value +n can mean a win in n+1 ply. This
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// cannot happen for tables with positions exactly on the "edge" of
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// the 50-move rule.
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//
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// This implies that if dtz > 0 is returned, the position is certainly
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// a win if dtz + 50-move-counter <= 99. Care must be taken that the engine
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// picks moves that preserve dtz + 50-move-counter <= 99.
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//
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// If n = 100 immediately after a capture or pawn move, then the position
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// is also certainly a win, and during the whole phase until the next
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// capture or pawn move, the inequality to be preserved is
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// dtz + 50-movecounter <= 100.
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//
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// In short, if a move is available resulting in dtz + 50-move-counter <= 99,
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// then do not accept moves leading to dtz + 50-move-counter == 100.
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//
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int probe_dtz(Position& pos, int *success)
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{
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*success = 1;
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int v = probe_dtz_no_ep(pos, success);
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if (pos.ep_square() == SQ_NONE)
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return v;
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if (*success == 0)
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return 0;
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// Now handle en passant.
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int v1 = -3;
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ExtMove stack[MAX_MOVES];
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ExtMove *moves, *end;
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StateInfo st;
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if (!pos.checkers())
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end = generate<CAPTURES>(pos, stack);
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else
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end = generate<EVASIONS>(pos, stack);
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CheckInfo ci(pos);
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for (moves = stack; moves < end; ++moves) {
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Move capture = moves->move;
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if (type_of(capture) != ENPASSANT
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|| !pos.legal(capture, ci.pinned))
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continue;
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pos.do_move(capture, st, pos.gives_check(capture, ci));
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WDLScore v0 = -probe_ab(pos, WDLHardLoss, WDLHardWin, success);
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pos.undo_move(capture);
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if (*success == 0)
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return 0;
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if (v0 > v1) v1 = v0;
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}
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if (v1 > -3) {
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v1 = wdl_to_dtz[v1 + 2];
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if (v < -100) {
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if (v1 >= 0)
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v = v1;
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} else if (v < 0) {
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if (v1 >= 0 || v1 < -100)
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v = v1;
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} else if (v > 100) {
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if (v1 > 0)
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v = v1;
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} else if (v > 0) {
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if (v1 == 1)
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v = v1;
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} else if (v1 >= 0) {
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v = v1;
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} else {
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for (moves = stack; moves < end; ++moves) {
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Move move = moves->move;
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if (type_of(move) == ENPASSANT) continue;
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if (pos.legal(move, ci.pinned))
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break;
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}
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if (moves == end && !pos.checkers()) {
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end = generate<QUIETS>(pos, end);
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for (; moves < end; ++moves) {
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Move move = moves->move;
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if (pos.legal(move, ci.pinned))
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break;
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}
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}
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if (moves == end)
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v = v1;
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}
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}
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return v;
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}
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} // namespace
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void Tablebases::free()
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@ -1895,236 +2127,6 @@ WDLScore Tablebases::probe_wdl(Position& pos, int *success)
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return v;
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}
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// This routine treats a position with en passant captures as one without.
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static int probe_dtz_no_ep(Position& pos, int *success)
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{
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int dtz;
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WDLScore wdl = probe_ab(pos, WDLHardLoss, WDLHardWin, success);
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if (*success == 0) return 0;
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if (wdl == WDLDraw) return 0;
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if (*success == 2)
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return wdl == WDLHardWin ? 1 : 101;
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ExtMove stack[MAX_MOVES];
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ExtMove *moves, *end = NULL;
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StateInfo st;
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CheckInfo ci(pos);
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if (wdl > 0) {
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// Generate at least all legal non-capturing pawn moves
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// including non-capturing promotions.
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if (!pos.checkers())
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end = generate<NON_EVASIONS>(pos, stack);
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else
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end = generate<EVASIONS>(pos, stack);
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for (moves = stack; moves < end; ++moves) {
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Move move = moves->move;
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if ( type_of(pos.moved_piece(move)) != PAWN
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|| pos.capture(move)
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|| !pos.legal(move, ci.pinned))
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continue;
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pos.do_move(move, st, pos.gives_check(move, ci));
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WDLScore v = -probe_ab(pos, WDLHardLoss, -wdl + WDLSoftWin, success);
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pos.undo_move(move);
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if (*success == 0) return 0;
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if (v == wdl)
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return v == WDLHardWin ? 1 : 101;
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}
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}
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dtz = 1 + probe_dtz_table(pos, wdl, success);
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if (*success >= 0) {
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if (wdl & 1) dtz += 100;
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return wdl >= 0 ? dtz : -dtz;
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}
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if (wdl > 0) {
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int best = 0xffff;
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for (moves = stack; moves < end; ++moves) {
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Move move = moves->move;
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if (pos.capture(move) || type_of(pos.moved_piece(move)) == PAWN
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|| !pos.legal(move, ci.pinned))
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continue;
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pos.do_move(move, st, pos.gives_check(move, ci));
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int v = -Tablebases::probe_dtz(pos, success);
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pos.undo_move(move);
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if (*success == 0)
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return 0;
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if (v > 0 && v + 1 < best)
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best = v + 1;
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}
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return best;
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} else {
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int best = -1;
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if (!pos.checkers())
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end = generate<NON_EVASIONS>(pos, stack);
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else
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end = generate<EVASIONS>(pos, stack);
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for (moves = stack; moves < end; ++moves) {
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int v;
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Move move = moves->move;
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if (!pos.legal(move, ci.pinned))
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continue;
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pos.do_move(move, st, pos.gives_check(move, ci));
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if (st.rule50 == 0) {
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if (wdl == -2) v = -1;
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else {
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v = probe_ab(pos, WDLSoftWin, WDLHardWin, success);
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v = (v == 2) ? 0 : -101;
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}
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} else {
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v = -Tablebases::probe_dtz(pos, success) - 1;
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}
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pos.undo_move(move);
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if (*success == 0)
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return 0;
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if (v < best)
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best = v;
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}
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return best;
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}
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}
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// Probe the DTZ table for a particular position.
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// If *success != 0, the probe was successful.
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// The return value is from the point of view of the side to move:
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// n < -100 : loss, but draw under 50-move rule
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// -100 <= n < -1 : loss in n ply (assuming 50-move counter == 0)
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// 0 : draw
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// 1 < n <= 100 : win in n ply (assuming 50-move counter == 0)
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// 100 < n : win, but draw under 50-move rule
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//
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// The return value n can be off by 1: a return value -n can mean a loss
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// in n+1 ply and a return value +n can mean a win in n+1 ply. This
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// cannot happen for tables with positions exactly on the "edge" of
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// the 50-move rule.
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//
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// This implies that if dtz > 0 is returned, the position is certainly
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// a win if dtz + 50-move-counter <= 99. Care must be taken that the engine
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// picks moves that preserve dtz + 50-move-counter <= 99.
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//
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// If n = 100 immediately after a capture or pawn move, then the position
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// is also certainly a win, and during the whole phase until the next
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// capture or pawn move, the inequality to be preserved is
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// dtz + 50-movecounter <= 100.
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//
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// In short, if a move is available resulting in dtz + 50-move-counter <= 99,
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// then do not accept moves leading to dtz + 50-move-counter == 100.
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//
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int Tablebases::probe_dtz(Position& pos, int *success)
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{
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*success = 1;
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int v = probe_dtz_no_ep(pos, success);
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if (pos.ep_square() == SQ_NONE)
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return v;
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if (*success == 0)
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return 0;
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// Now handle en passant.
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int v1 = -3;
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ExtMove stack[MAX_MOVES];
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ExtMove *moves, *end;
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StateInfo st;
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if (!pos.checkers())
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end = generate<CAPTURES>(pos, stack);
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else
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end = generate<EVASIONS>(pos, stack);
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CheckInfo ci(pos);
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for (moves = stack; moves < end; ++moves) {
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Move capture = moves->move;
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if (type_of(capture) != ENPASSANT
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|| !pos.legal(capture, ci.pinned))
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continue;
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pos.do_move(capture, st, pos.gives_check(capture, ci));
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WDLScore v0 = -probe_ab(pos, WDLHardLoss, WDLHardWin, success);
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pos.undo_move(capture);
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if (*success == 0)
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return 0;
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if (v0 > v1) v1 = v0;
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}
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if (v1 > -3) {
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v1 = wdl_to_dtz[v1 + 2];
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if (v < -100) {
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if (v1 >= 0)
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v = v1;
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} else if (v < 0) {
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if (v1 >= 0 || v1 < -100)
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v = v1;
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} else if (v > 100) {
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if (v1 > 0)
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v = v1;
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} else if (v > 0) {
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if (v1 == 1)
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v = v1;
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} else if (v1 >= 0) {
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v = v1;
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} else {
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for (moves = stack; moves < end; ++moves) {
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Move move = moves->move;
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if (type_of(move) == ENPASSANT) continue;
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if (pos.legal(move, ci.pinned))
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break;
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}
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if (moves == end && !pos.checkers()) {
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end = generate<QUIETS>(pos, end);
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for (; moves < end; ++moves) {
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Move move = moves->move;
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if (pos.legal(move, ci.pinned))
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break;
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}
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}
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if (moves == end)
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v = v1;
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}
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}
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return v;
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}
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// Check whether there has been at least one repetition of positions
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// since the last capture or pawn move.
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static int has_repeated(StateInfo *st)
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@ -2182,14 +2184,14 @@ bool Tablebases::root_probe(Position& pos, Search::RootMoves& rootMoves, Value&
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if (!v) {
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if (st.rule50 != 0) {
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v = -Tablebases::probe_dtz(pos, &success);
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v = -probe_dtz(pos, &success);
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if (v > 0)
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++v;
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else if (v < 0)
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--v;
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} else {
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v = -Tablebases::probe_wdl(pos, &success);
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v = -probe_wdl(pos, &success);
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v = wdl_to_dtz[v + 2];
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -18,7 +18,6 @@ extern int MaxCardinality;
|
|||
void init(const std::string& paths);
|
||||
void free();
|
||||
WDLScore probe_wdl(Position& pos, int* success);
|
||||
int probe_dtz(Position& pos, int* success);
|
||||
bool root_probe(Position& pos, Search::RootMoves& rootMoves, Value& score);
|
||||
bool root_probe_wdl(Position& pos, Search::RootMoves& rootMoves, Value& score);
|
||||
|
||||
|
|
|
|||
Loading…
Add table
Reference in a new issue