/// <summary>
/// Probes the transposition table for a entry that matches the position key.
/// </summary>
/// <param name="key">The position key</param>
/// <returns>(true, entry) if one was found, (false, empty) if not found</returns>
public (bool, TranspositionTableEntry) Probe(HashKey key)
{
var ttc = FindCluster(key);
var g = _generation;
// Probing the Table will automatically update the generation of the entry in case the
// probing retrieves an element.
TranspositionTableEntry e = default;
var set = false;
for (var i = 0; i < ttc.Cluster.Length; ++i)
{
if (ttc.Cluster[i].Key32 != 0 && ttc.Cluster[i].Key32 != key.UpperKey)
{
continue;
}
ttc.Cluster[i].Generation = g;
e = ttc.Cluster[i];
set = true;
Hits++;
break;
}
return(set, !set ? TTCluster.DefaultEntry : e);
}
public void Save(TranspositionTableEntry tte)
{
Key32 = tte.Key32;
if (!tte.Move.IsNullMove())
{
Move = tte.Move;
}
Depth = tte.Depth;
Generation = tte.Generation;
Value = tte.Value;
StaticValue = tte.StaticValue;
Type = tte.Type;
}
/// <summary>
/// Stores a move in the transposition table. It will automatically detect the best cluster
/// location to store it in. If a similar move already is present, a simple check if done to
/// make sure it actually is an improvement of the previous move.
/// </summary>
/// <param name="key">The position key</param>
/// <param name="value">The value of the move</param>
/// <param name="type">The bound type, e.i. did it exceed alpha or beta</param>
/// <param name="depth">The depth of the move</param>
/// <param name="move">The move it self</param>
/// <param name="statValue">The static value of the move</param>
public void Store(HashKey key, int value, Bound type, sbyte depth, Move move, int statValue)
{
var ttc = FindCluster(key);
var clusterIndex = 0;
var found = false;
for (var i = 0; i < ttc.Cluster.Length; ++i)
{
if (ttc.Cluster[i].Key32 != 0 && ttc.Cluster[i].Key32 != key.UpperKey)
{
continue;
}
clusterIndex = i;
found = true;
break;
}
if (!found)
{
var index = 0;
var candidate = ttc.Cluster[index];
var g = _generation;
var i = 0;
foreach (var ttEntry in ttc.Cluster)
{
var(cc1, cc2, cc3, cc4) =
(candidate.Generation == g,
ttEntry.Generation == g,
ttEntry.Type == Bound.Exact,
ttEntry.Depth <= candidate.Depth);
if (cc1 && cc4 || !(cc2 || cc3) && (cc4 || cc1))
{
index = i;
candidate = ttEntry;
}
i++;
}
clusterIndex = index;
}
var e = new TranspositionTableEntry(key.UpperKey, move, depth, _generation, value, statValue, type);
ttc.Cluster[clusterIndex].Save(e);
}
public void Refresh(TranspositionTableEntry tte) => tte.Generation = _generation;
public readonly bool Equals(TranspositionTableEntry other) => Key32 == other.Key32 && Generation == other.Generation;
public TranspositionTableEntry(TranspositionTableEntry tte)
{
this = tte;
}
