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Code Issues Releases Wiki Activity

Retire pv[] from SearchStack

Browse source 
Extract PV info from TT instead of using
a set of arrays. This is almost equivalent
except for cases when TT is full and the PV entry
is overwritten, but this is very rare.

(Almost) No functional change

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba 2010-06-26 15:05:38 +01:00
parent 0a687b2cf0
commit adb43cc0cc
3 changed files with 38 additions and 51 deletions
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82
src/search.cpp
View file

@ -282,7 +282,7 @@ namespace {
/// Local functions
Value id_loop(const Position& pos, Move searchMoves[]);
Value root_search(Position& pos, SearchStack* ss, RootMoveList& rml, Value* alphaPtr, Value* betaPtr);
Value root_search(Position& pos, SearchStack* ss, Move* pv, RootMoveList& rml, Value* alphaPtr, Value* betaPtr);
template <NodeType PvNode>
Value search(Position& pos, SearchStack* ss, Value alpha, Value beta, Depth depth, int ply);
@ -314,7 +314,7 @@ namespace {
void ponderhit();
void wait_for_stop_or_ponderhit();
void init_ss_array(SearchStack* ss, int size);
void print_pv_info(const Position& pos, SearchStack* ss, Value alpha, Value beta, Value value);
void print_pv_info(const Position& pos, Move* ss, Value alpha, Value beta, Value value);
#if !defined(_MSC_VER)
void *init_thread(void *threadID);
@ -368,8 +368,7 @@ void init_search() {
// Called at the beginning of search() when starting to examine a new node.
void SearchStack::init() {
pv[0] = pv[1] = bestMove = MOVE_NONE;
currentMove = threatMove = MOVE_NONE;
currentMove = threatMove = bestMove = MOVE_NONE;
reduction = Depth(0);
eval = VALUE_NONE;
}
@ -606,6 +605,7 @@ namespace {
Position p(pos, pos.thread());
SearchStack ss[PLY_MAX_PLUS_2];
Move pv[PLY_MAX_PLUS_2];
Move EasyMove = MOVE_NONE;
Value value, alpha = -VALUE_INFINITE, beta = VALUE_INFINITE;
@ -635,6 +635,7 @@ namespace {
TT.new_search();
H.clear();
init_ss_array(ss, PLY_MAX_PLUS_2);
pv[0] = pv[1] = MOVE_NONE;
ValueByIteration[1] = rml.get_move_score(0);
Iteration = 1;
@ -666,11 +667,11 @@ namespace {
}
// Search to the current depth, rml is updated and sorted, alpha and beta could change
value = root_search(p, ss, rml, &alpha, &beta);
value = root_search(p, ss, pv, rml, &alpha, &beta);
// Write PV to transposition table, in case the relevant entries have
// been overwritten during the search.
TT.insert_pv(p, ss->pv);
TT.insert_pv(p, pv);
if (AbortSearch)
break; // Value cannot be trusted. Break out immediately!
@ -679,7 +680,7 @@ namespace {
ValueByIteration[Iteration] = value;
// Drop the easy move if differs from the new best move
if (ss->pv[0] != EasyMove)
if (pv[0] != EasyMove)
EasyMove = MOVE_NONE;
if (UseTimeManagement)
@ -701,7 +702,7 @@ namespace {
// Stop search early if one move seems to be much better than the others
int64_t nodes = TM.nodes_searched();
if ( Iteration >= 8
&& EasyMove == ss->pv[0]
&& EasyMove == pv[0]
&& ( ( rml.get_move_cumulative_nodes(0) > (nodes * 85) / 100
&& current_search_time() > MaxSearchTime / 16)
||( rml.get_move_cumulative_nodes(0) > (nodes * 98) / 100
@ -744,18 +745,18 @@ namespace {
<< " hashfull " << TT.full() << endl;
// Print the best move and the ponder move to the standard output
if (ss->pv[0] == MOVE_NONE)
if (pv[0] == MOVE_NONE)
{
ss->pv[0] = rml.get_move(0);
ss->pv[1] = MOVE_NONE;
pv[0] = rml.get_move(0);
pv[1] = MOVE_NONE;
}
assert(ss->pv[0] != MOVE_NONE);
assert(pv[0] != MOVE_NONE);
cout << "bestmove " << ss->pv[0];
cout << "bestmove " << pv[0];
if (ss->pv[1] != MOVE_NONE)
cout << " ponder " << ss->pv[1];
if (pv[1] != MOVE_NONE)
cout << " ponder " << pv[1];
cout << endl;
@ -769,12 +770,12 @@ namespace {
LogFile << "\nNodes: " << TM.nodes_searched()
<< "\nNodes/second: " << nps()
<< "\nBest move: " << move_to_san(p, ss->pv[0]);
<< "\nBest move: " << move_to_san(p, pv[0]);
StateInfo st;
p.do_move(ss->pv[0], st);
p.do_move(pv[0], st);
LogFile << "\nPonder move: "
<< move_to_san(p, ss->pv[1]) // Works also with MOVE_NONE
<< move_to_san(p, pv[1]) // Works also with MOVE_NONE
<< endl;
}
return rml.get_move_score(0);
@ -786,7 +787,7 @@ namespace {
// scheme, prints some information to the standard output and handles
// the fail low/high loops.
Value root_search(Position& pos, SearchStack* ss, RootMoveList& rml, Value* alphaPtr, Value* betaPtr) {
Value root_search(Position& pos, SearchStack* ss, Move* pv, RootMoveList& rml, Value* alphaPtr, Value* betaPtr) {
EvalInfo ei;
StateInfo st;
@ -937,11 +938,12 @@ namespace {
// the score before research in case we run out of time while researching.
rml.set_move_score(i, value);
update_pv(ss);
TT.extract_pv(pos, ss->pv, PLY_MAX);
rml.set_move_pv(i, ss->pv);
pv[0] = ss->bestMove;
TT.extract_pv(pos, pv, PLY_MAX);
rml.set_move_pv(i, pv);
// Print information to the standard output
print_pv_info(pos, ss, alpha, beta, value);
print_pv_info(pos, pv, alpha, beta, value);
// Prepare for a research after a fail high, each time with a wider window
*betaPtr = beta = Min(beta + AspirationDelta * (1 << researchCountFH), VALUE_INFINITE);
@ -977,8 +979,9 @@ namespace {
// Update PV
rml.set_move_score(i, value);
update_pv(ss);
TT.extract_pv(pos, ss->pv, PLY_MAX);
rml.set_move_pv(i, ss->pv);
pv[0] = ss->bestMove;
TT.extract_pv(pos, pv, PLY_MAX);
rml.set_move_pv(i, pv);
if (MultiPV == 1)
{
@ -989,7 +992,7 @@ namespace {
BestMoveChangesByIteration[Iteration]++;
// Print information to the standard output
print_pv_info(pos, ss, alpha, beta, value);
print_pv_info(pos, pv, alpha, beta, value);
// Raise alpha to setup proper non-pv search upper bound
if (value > alpha)
@ -1487,7 +1490,7 @@ namespace {
Value oldAlpha = alpha;
TM.incrementNodeCounter(pos.thread());
ss->pv[0] = ss->pv[1] = ss->bestMove = ss->currentMove = MOVE_NONE;
ss->bestMove = ss->currentMove = MOVE_NONE;
ss->eval = VALUE_NONE;
// Check for an instant draw or maximum ply reached
@ -1813,14 +1816,7 @@ namespace {
void update_pv(SearchStack* ss) {
Move* src = (ss+1)->pv;
Move* dst = ss->pv;
*dst = ss->bestMove = ss->currentMove;
do
*++dst = *src;
while (*src++ != MOVE_NONE);
ss->bestMove = ss->currentMove;
}
@ -1830,15 +1826,7 @@ namespace {
void sp_update_pv(SearchStack* pss, SearchStack* ss) {
Move* src = (ss+1)->pv;
Move* dst = ss->pv;
Move* pdst = pss->pv;
*dst = *pdst = pss->bestMove = ss->bestMove = ss->currentMove;
do
*++dst = *++pdst = *src;
while (*src++ != MOVE_NONE);
pss->bestMove = ss->bestMove = ss->currentMove;
}
@ -2280,7 +2268,7 @@ namespace {
// print_pv_info() prints to standard output and eventually to log file information on
// the current PV line. It is called at each iteration or after a new pv is found.
void print_pv_info(const Position& pos, SearchStack* ss, Value alpha, Value beta, Value value) {
void print_pv_info(const Position& pos, Move* pv, Value alpha, Value beta, Value value) {
cout << "info depth " << Iteration
<< " score " << value_to_string(value)
@ -2291,8 +2279,8 @@ namespace {
<< " nps " << nps()
<< " pv ";
for (int j = 0; ss->pv[j] != MOVE_NONE && j < PLY_MAX; j++)
cout << ss->pv[j] << " ";
for (int j = 0; pv[j] != MOVE_NONE && j < PLY_MAX; j++)
cout << pv[j] << " ";
cout << endl;
@ -2302,7 +2290,7 @@ namespace {
: (value <= alpha ? VALUE_TYPE_UPPER : VALUE_TYPE_EXACT));
LogFile << pretty_pv(pos, current_search_time(), Iteration,
TM.nodes_searched(), value, type, ss->pv) << endl;
TM.nodes_searched(), value, type, pv) << endl;
}
}

1
src/search.h
View file

@ -50,7 +50,6 @@ const int KILLER_MAX = 2;
struct EvalInfo;
struct SearchStack {
Move pv[PLY_MAX_PLUS_2];
Move currentMove;
Move mateKiller;
Move threatMove;

6
src/tt.cpp
View file

@ -192,9 +192,9 @@ void TranspositionTable::extract_pv(const Position& pos, Move pv[], const int PL
Position p(pos, pos.thread());
int ply = 0;
// Update position to the end of current PV
while (pv[ply] != MOVE_NONE)
p.do_move(pv[ply++], st);
assert(pv[0] != MOVE_NONE);
p.do_move(pv[ply++], st);
// Try to add moves from TT while possible
while ( (tte = retrieve(p.get_key())) != NULL