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Use float instead of double in reduction parameters

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This is faster on 32 bit CPU and precision is enough.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This commit is contained in:
Marco Costalba
2010-01-28 12:47:48 +01:00
parent 1d7a3f26e0
commit e4d3a15656
1 changed files with 15 additions and 15 deletions
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30
src/search.cpp
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@@ -239,8 +239,8 @@ namespace {
std::ofstream LogFile;
// Natural logarithmic lookup table and its getter function
double lnArray[512];
inline double ln(int i) { return lnArray[i]; }
float lnArray[512];
inline float ln(int i) { return lnArray[i]; }
// MP related variables
int ActiveThreads = 1;
@@ -288,8 +288,8 @@ namespace {
bool ok_to_prune(const Position& pos, Move m, Move threat);
bool ok_to_use_TT(const TTEntry* tte, Depth depth, Value beta, int ply);
Value refine_eval(const TTEntry* tte, Value defaultEval, int ply);
void reduction_parameters(double base, double Inhibitor, Depth depth, double& logLimit, double& gradient);
Depth reduction(int moveCount, const double LogLimit, const double BaseRed, const double Gradient);
void reduction_parameters(float base, float Inhibitor, Depth depth, float& logLimit, float& gradient);
Depth reduction(int moveCount, const float LogLimit, const float BaseRed, const float Gradient);
void update_history(const Position& pos, Move move, Depth depth, Move movesSearched[], int moveCount);
void update_killers(Move m, SearchStack& ss);
void update_gains(const Position& pos, Move move, Value before, Value after);
@@ -574,7 +574,7 @@ void init_threads() {
// Init our logarithmic lookup table
for (i = 0; i < 512; i++)
lnArray[i] = log(double(i)); // log() returns base-e logarithm
lnArray[i] = float(log(double(i))); // log() returns base-e logarithm
for (i = 0; i < THREAD_MAX; i++)
Threads[i].activeSplitPoints = 0;
@@ -966,7 +966,7 @@ namespace {
value = - VALUE_INFINITE;
// Precalculate reduction parameters
double LogLimit, Gradient, BaseReduction = 0.5;
float LogLimit, Gradient, BaseReduction = 0.5;
reduction_parameters(BaseReduction, 6.0, depth, LogLimit, Gradient);
while (1) // Fail high loop
@@ -1260,7 +1260,7 @@ namespace {
MovePicker mp = MovePicker(pos, ttMove, depth, H, &ss[ply]);
// Precalculate reduction parameters
double LogLimit, Gradient, BaseReduction = 0.5;
float LogLimit, Gradient, BaseReduction = 0.5;
reduction_parameters(BaseReduction, 6.0, depth, LogLimit, Gradient);
// Loop through all legal moves until no moves remain or a beta cutoff
@@ -1583,7 +1583,7 @@ namespace {
CheckInfo ci(pos);
// Precalculate reduction parameters
double LogLimit, Gradient, BaseReduction = 0.5;
float LogLimit, Gradient, BaseReduction = 0.5;
reduction_parameters(BaseReduction, 3.0, depth, LogLimit, Gradient);
// Loop through all legal moves until no moves remain or a beta cutoff occurs
@@ -1998,7 +1998,7 @@ namespace {
const int FutilityMoveCountMargin = 3 + (1 << (3 * int(sp->depth) / 8));
// Precalculate reduction parameters
double LogLimit, Gradient, BaseReduction = 0.5;
float LogLimit, Gradient, BaseReduction = 0.5;
reduction_parameters(BaseReduction, 3.0, sp->depth, LogLimit, Gradient);
while ( lock_grab_bool(&(sp->lock))
@@ -2142,7 +2142,7 @@ namespace {
Move move;
// Precalculate reduction parameters
double LogLimit, Gradient, BaseReduction = 0.5;
float LogLimit, Gradient, BaseReduction = 0.5;
reduction_parameters(BaseReduction, 6.0, sp->depth, LogLimit, Gradient);
while ( lock_grab_bool(&(sp->lock))
@@ -2710,26 +2710,26 @@ namespace {
// floating point operations are involved we try to recalculate reduction at each move, but
// we do the most consuming computation only once per node.
void reduction_parameters(double baseReduction, double reductionInhibitor, Depth depth, double& logLimit, double& gradient)
void reduction_parameters(float baseReduction, float reductionInhibitor, Depth depth, float& logLimit, float& gradient)
{
// Precalculate some parameters to avoid to calculate the following formula for each move:
//
// red = baseReduction + ln(moveCount) * ln(depth / 2) / reductionInhibitor;
//
logLimit = depth > OnePly ? (1.0 - baseReduction) * reductionInhibitor / ln(depth / 2) : 1000.0;
gradient = depth > OnePly ? ln(depth / 2) / reductionInhibitor : 0.0;
logLimit = depth > OnePly ? (1 - baseReduction) * reductionInhibitor / ln(depth / 2) : 1000;
gradient = depth > OnePly ? ln(depth / 2) / reductionInhibitor : 0;
}
// reduction() returns reduction in plies based on moveCount and depth.
// Reduction is always at least one ply.
Depth reduction(int moveCount, double logLimit, double baseReduction, double gradient) {
Depth reduction(int moveCount, float logLimit, float baseReduction, float gradient) {
if (ln(moveCount) < logLimit)
return Depth(0);
double red = baseReduction + ln(moveCount) * gradient;
float red = baseReduction + ln(moveCount) * gradient;
return Depth(int(floor(red * int(OnePly))));
}