private int alphabeta(Coordinate field, int boardvalue, int alpha, int beta, int depthbound, int depth
#if PRETTY
, string parent
#endif
)
{
#if STATS
++nodesvisited;
depthnodes[depth]++;
if (depth > maxdepth)
{
maxdepth = depth;
}
#endif
++expirenodecnt;
if (expirenodecnt >= 3000)
{
expirenodecnt = 0;
//Console.WriteLine("Checking timeout: {0}", DateTime.Now);
if (DateTime.Now > expiretime)
{
//Console.WriteLine("Timeout: {0}", DateTime.Now);
throw new ABSearchTimeoutException();
}
}
int attacker = (depth % 2 == 0) ? 1 : -1;
InterestingFieldAgent fieldagentbackup = (InterestingFieldAgent)fieldagent.Clone();
board[field.X, field.Y] = -1 * attacker; // remember: field comes still from the upper level.
fieldagent.UpdateInterestingFieldArray(board, field);
fieldagent.UpdateThreatLists(board, field, -1 * attacker);
boardvalue += field.Val;
#if PRETTY
string thisnode = "" + nodesvisited;
if (nodesvisited < 250)
{
string infostring = "";
infostring += "<table>";
infostring += "<tr><td>";
infostring += "node: " + thisnode + "-" + depthnodes[depth] + ", boardval: " + boardvalue + ", moveval: " + eval.statVal(board, field, -1 * attacker);
infostring += "</td></tr>";
infostring += "<tr><td>compare val: " + field.Val + "</td></tr>";
infostring += "<tr><td>last move from: " + attacker * -1 + "</td></tr>";
infostring += "<tr><td>Own threats: " + fieldagent.ownthreatlist.Count + "</td></tr>";
foreach (Threat t in fieldagent.ownthreatlist)
{
infostring += "<tr><td>cat : " + t.category + "</td></tr>";
foreach (Coordinate c in t.fields)
{
infostring += "<tr><td>coord : " + c + "</td></tr>";
}
}
infostring += "<tr><td>Own threats added: " + fieldagent.ownaddedthreatlist.Count + "</td></tr>";
foreach (Threat t in fieldagent.ownaddedthreatlist)
{
infostring += "<tr><td>cat : " + t.category + "</td></tr>";
foreach (Coordinate c in t.fields)
{
infostring += "<tr><td>coord : " + c + "</td></tr>";
}
}
infostring += "<tr><td>Own threats removed: " + fieldagent.ownremovedthreatlist.Count + "</td></tr>";
foreach (Threat t in fieldagent.ownremovedthreatlist)
{
infostring += "<tr><td>cat : " + t.category + "</td></tr>";
foreach (Coordinate c in t.fields)
{
infostring += "<tr><td>coord : " + c + "</td></tr>";
}
}
infostring += "<tr><td>Opp threats: " + fieldagent.oppthreatlist.Count + "</td></tr>";
foreach (Threat t in fieldagent.oppthreatlist)
{
infostring += "<tr><td>cat : " + t.category + "</td></tr>";
foreach (Coordinate c in t.fields)
{
infostring += "<tr><td>coord : " + c + "</td></tr>";
}
}
infostring += "<tr><td>Opp threats added: " + fieldagent.oppaddedthreatlist.Count + "</td></tr>";
foreach (Threat t in fieldagent.oppaddedthreatlist)
{
infostring += "<tr><td>cat : " + t.category + "</td></tr>";
foreach (Coordinate c in t.fields)
{
infostring += "<tr><td>coord : " + c + "</td></tr>";
}
}
infostring += "<tr><td>Opp threats removed: " + fieldagent.oppremovedthreatlist.Count + "</td></tr>";
foreach (Threat t in fieldagent.oppremovedthreatlist)
{
infostring += "<tr><td>cat : " + t.category + "</td></tr>";
foreach (Coordinate c in t.fields)
{
infostring += "<tr><td>coord : " + c + "</td></tr>";
}
}
infostring += "</table>";
PrettyPrint.PrintBoard(wr, thisnode, board, infostring);
wr.WriteLine("{0} -> {1};", parent, nodesvisited);
}
#endif
if (boardvalue > StatValEvaluator.WINBORDER || boardvalue < -StatValEvaluator.WINBORDER)
{
board[field.X, field.Y] = 0;
if (attacker == 1)
{
return(boardvalue - depth * 10000);
}
else
{
return(boardvalue + depth * 10000);
}
}
if (depth == depthbound)
{
board[field.X, field.Y] = 0;
return(boardvalue);
}
ArrayList fields = null;
if (depth == 0)
{
fields = firstMoveFields;
}
else
{
fields = fieldagent.ReallyInterestingFields(board, attacker);
}
// Calculate the static value for all fields
for (int i = 0; i < fields.Count; ++i)
{
Coordinate c = (Coordinate)fields[i];
board[c.X, c.Y] = attacker;
InterestingFieldAgent valifabackup = (InterestingFieldAgent)fieldagent.Clone();
fieldagent.UpdateThreatLists(board, c, attacker);
c.Val = eval.statVal(board, c, attacker);
fieldagent = valifabackup;
board[c.X, c.Y] = 0;
fields[i] = c;
}
fields.Sort();
if (depth % 2 == 0)
{
//MAX node
fields.Reverse();
foreach (Coordinate ifield in fields)
{
int max = alpha;
if ((max = alphabeta(ifield, boardvalue, alpha, beta, depthbound, depth + 1
#if PRETTY
, thisnode
#endif
)) > alpha)
{
alpha = max;
if (depth == 0)
{
tmpbestfield = ifield;
}
}
if (depth == 0)
{
Console.WriteLine("Got max from {0}: {1}", ifield, max);
}
if (alpha >= beta)
{
fieldagent = fieldagentbackup;
if (depth == 0)
{
tmpbestfield = ifield;
}
board[field.X, field.Y] = 0;
return(beta);
}
}
fieldagent = fieldagentbackup;
board[field.X, field.Y] = 0;
return(alpha);
}
else
{
//MIN node
foreach (Coordinate ifield in fields)
{
if (depth == 0)
{
tmpbestfield = ifield;
}
int min = beta;
if ((min = alphabeta(ifield, boardvalue, alpha, beta, depthbound, depth + 1
#if PRETTY
, thisnode
#endif
)) < beta)
{
beta = min;
if (depth == 0)
{
tmpbestfield = ifield;
}
}
if (alpha >= beta)
{
fieldagent = fieldagentbackup;
if (depth == 0)
{
tmpbestfield = ifield;
}
board[field.X, field.Y] = 0;
return(alpha);
}
}
fieldagent = fieldagentbackup;
board[field.X, field.Y] = 0;
return(beta);
}
}
