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Small reformat to Skill class

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Steamline a bit the implementation of
skill levels. As a side effect we can
retire MultiPV global and use a local
variable instead.

No functional change.
This commit is contained in:
Marco Costalba
2014-07-10 16:40:10 +02:00
committed by lucasart
parent f133f61e3f
commit 94b1bbb68b
1 changed files with 19 additions and 19 deletions
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38
src/search.cpp
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@@ -73,7 +73,7 @@ namespace {
return (Depth) Reductions[PvNode][i][std::min(int(d) / ONE_PLY, 63)][std::min(mn, 63)];
}
size_t MultiPV, PVIdx;
size_t PVIdx;
TimeManager TimeMgr;
double BestMoveChanges;
Value DrawValue[COLOR_NB];
@@ -94,18 +94,21 @@ namespace {
string uci_pv(const Position& pos, int depth, Value alpha, Value beta);
struct Skill {
Skill(int l) : level(l), best(MOVE_NONE) {}
Skill(int l, int rootSize) : level(l),
candidates(l < 20 ? std::min(4, rootSize) : 0),
best(MOVE_NONE) {}
~Skill() {
if (enabled()) // Swap best PV line with the sub-optimal one
if (candidates) // Swap best PV line with the sub-optimal one
std::swap(RootMoves[0], *std::find(RootMoves.begin(),
RootMoves.end(), best ? best : pick_move()));
}
bool enabled() const { return level < 20; }
size_t candidates_size() const { return candidates; }
bool time_to_pick(int depth) const { return depth == 1 + level; }
Move pick_move();
int level;
size_t candidates;
Move best;
};
@@ -279,15 +282,12 @@ namespace {
Countermoves.clear();
Followupmoves.clear();
MultiPV = Options["MultiPV"];
Skill skill(Options["Skill Level"]);
size_t multiPV = Options["MultiPV"];
Skill skill(Options["Skill Level"], RootMoves.size());
// Do we have to play with skill handicap? In this case enable MultiPV search
// that we will use behind the scenes to retrieve a set of possible moves.
if (skill.enabled() && MultiPV < 4)
MultiPV = 4;
MultiPV = std::min(MultiPV, RootMoves.size());
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))
@@ -301,7 +301,7 @@ namespace {
RootMoves[i].prevScore = RootMoves[i].score;
// MultiPV loop. We perform a full root search for each PV line
for (PVIdx = 0; PVIdx < MultiPV && !Signals.stop; ++PVIdx)
for (PVIdx = 0; PVIdx < multiPV && PVIdx < RootMoves.size() && !Signals.stop; ++PVIdx)
{
// Reset aspiration window starting size
if (depth >= 5)
@@ -366,12 +366,12 @@ namespace {
// Sort the PV lines searched so far and update the GUI
std::stable_sort(RootMoves.begin(), RootMoves.begin() + PVIdx + 1);
if (PVIdx + 1 == MultiPV || Time::now() - SearchTime > 3000)
if (PVIdx + 1 == multiPV || Time::now() - SearchTime > 3000)
sync_cout << uci_pv(pos, depth, alpha, beta) << sync_endl;
}
// If skill levels are enabled and time is up, pick a sub-optimal best move
if (skill.enabled() && skill.time_to_pick(depth))
if (skill.candidates_size() && skill.time_to_pick(depth))
skill.pick_move();
if (Options["Write Search Log"])
@@ -395,7 +395,7 @@ namespace {
if (Limits.use_time_management() && !Signals.stop && !Signals.stopOnPonderhit)
{
// Take some extra time if the best move has changed
if (depth > 4 && MultiPV == 1)
if (depth > 4 && multiPV == 1)
TimeMgr.pv_instability(BestMoveChanges);
// Stop the search if only one legal move is available or all
@@ -1292,8 +1292,8 @@ moves_loop: // When in check and at SpNode search starts from here
}
// When playing with a strength handicap, choose best move among the MultiPV
// set using a statistical rule dependent on 'level'. Idea by Heinz van Saanen.
// When playing with a strength handicap, choose best move among the first 'candidates'
// RootMoves using a statistical rule dependent on 'level'. Idea by Heinz van Saanen.
Move Skill::pick_move() {
@@ -1304,7 +1304,7 @@ moves_loop: // When in check and at SpNode search starts from here
rk.rand<unsigned>();
// RootMoves are already sorted by score in descending order
int variance = std::min(RootMoves[0].score - RootMoves[MultiPV - 1].score, PawnValueMg);
int variance = std::min(RootMoves[0].score - RootMoves[candidates - 1].score, PawnValueMg);
int weakness = 120 - 2 * level;
int max_s = -VALUE_INFINITE;
best = MOVE_NONE;
@@ -1312,12 +1312,12 @@ moves_loop: // When in check and at SpNode search starts from here
// Choose best move. For each move score we add two terms both dependent on
// weakness. One deterministic and bigger for weaker moves, and one random,
// then we choose the move with the resulting highest score.
for (size_t i = 0; i < MultiPV; ++i)
for (size_t i = 0; i < candidates; ++i)
{
int s = RootMoves[i].score;
// Don't allow crazy blunders even at very low skills
if (i > 0 && RootMoves[i-1].score > s + 2 * PawnValueMg)
if (i > 0 && RootMoves[i - 1].score > s + 2 * PawnValueMg)
break;
// This is our magic formula