Implement randomizing

The first 10 half-moves are now randomized by adding a small random bonus
to each move in the root.

diff --git a/dropper.c b/dropper.c
index 2c5fbae..f0975d5 100644 (file)
--- a/dropper.c
+++ b/dropper.c
@@ -40,6 +40,8 @@ int ReadClock (int start);
 char *MoveToText (int move);
 int TimeIsUp (int mode);
 
+int randomize, ranKey;
+int moveNr;              // part of game state; incremented by MakeMove
 
 #define captCode (rawInts + 22*10 + 10)
 #define deltaVec (rawChar + 22*10 + 10)
@@ -894,7 +896,7 @@ Search (int stm, int alpha, int beta, StackFrame *ff, int depth, int reduction,
     int oldSP = moveSP, *pvStart = pvPtr;
     int killer1 = killers[ply][0], killer2 = killers[ply][1], hashMove;
     int bestNr, bestScore, startAlpha, startScore, resultDepth, iterDepth=0;
-    int hit, hashKeyH;
+    int hit, hashKeyH, ran=0;
     int curEval, score;
 
     // legality
@@ -1092,10 +1094,11 @@ if(PATH)printf("%d:%d:%d new iter moveStack[%d..%d]\n",ply,depth,iterDepth,m.fir
                    int lmr;
                  search:
                    lmr = (curMove >= m.late) + (curMove >= m.drops);
+                   if(ply==0 && randomize && moveNr < 10) ran = (alpha > INF-100 || alpha <-INF+100 ? 0 : (f.newKey*ranKey>>24 & 31)- 16);
                    repKey[index] = (int)f.newKey & 0x1FFFFF | f.newEval << 21; // remember position
                    // recursion
                    deprec[ply] = (f.checker != CK_NONE ? f.checker : 0)<<24 | maxDepth<<16 | depth<< 8 | iterDepth; path[ply++] = moveStack[curMove];
-                   score = -Search(stm, -beta, -alpha, &f, iterDepth-1, lmr, highDepth);
+                   score = ran - Search(stm, -beta, -alpha+ran, &f, iterDepth-1, lmr, highDepth);
                    ply--;
 
                    repKey[index] = 0;
@@ -1185,7 +1188,6 @@ if(PATH || f.hashKey == 0x1348708590)printf("%d:%d   Hash store %16llx, d=%d, ch
     return bestScore;
 }
 
-int moveNr;              // part of game state; incremented by MakeMove
 int gameMove[MAXMOVES];  // holds the game history
 int stm = WHITE;
 
@@ -1331,7 +1333,6 @@ printf("# move = %08x\n", m);
 
 // Some global variables that control your engine's behavior
 int ponder;
-int randomize;
 int resign;         // engine-defined option
 int contemptFactor; // likewise
 
@@ -1385,7 +1386,7 @@ RootMakeMove(int move)
   index = (unsigned int)undoInfo.newKey >> 24 ^ stm << 2; // uses high byte of low (= hands-free) key
   while(repKey[index] && (repKey[index] ^ (int)undoInfo.newKey) & 0x1FFFFF) index += 2; // find empty slot
   repKey[index] = (int)undoInfo.newKey & 0x1FFFFF | undoInfo.newEval << 21; // remember position
-  stm ^= COLOR;
+  stm ^= COLOR; moveNr++;
   return 1;
 }
 
@@ -1477,7 +1478,7 @@ printf("# command: %s\n", inBuf);
     if(!strcmp(command, "memory"))  { if(SetMemorySize(atoi(inBuf+7))) printf("tellusererror Not enough memory\n"), exit(-1); return 1; }
     if(!strcmp(command, "ping"))    { printf("pong%s", inBuf+4); return 1; }
 //  if(!strcmp(command, ""))        { sscanf(inBuf, " %d", &); return 1; }
-    if(!strcmp(command, "new"))     { engineSide = BLACK; stm = WHITE; maxDepth = MAXPLY; randomize = OFF; return 1; }
+    if(!strcmp(command, "new"))     { engineSide = BLACK; stm = WHITE; maxDepth = MAXPLY; randomize = OFF; moveNr = 0; ranKey = GetTickCount() | 0x1001; return 1; }
     if(!strcmp(command, "variant")) { GameInit(inBuf + 8); Setup(startPos); return 1; }
     if(!strcmp(command, "setboard")){ engineSide = NONE;  stm = Setup(inBuf+9); return 1; }
     if(!strcmp(command, "undo"))    { TakeBack(1); return 1; }