I'm facing a problem with negamax. Think it comes from my eval function but i'm not sure at all.
First, can you tell me if my negamax and his call are ok ?
Because i don't find any solution, even if i read a lot about it these days.
Before showing you the code, i have to tell you that my verification function is based on (x,y) position (correspond to the last coin inserted with X = column and Y = line). Is this a portable method with negamax/alpha-beta or do i have to check the entire grid ?
Here is my negamax function:
int IA_NegaMaxAlphaBeta(int profondeur, int alpha, int beta, int grille[LIGNES][COLONNES], int emplacements[COLONNES], int colonne, int emplacement, int joueur)
{
int x = COLONNES/2, y, i, k = 1;
if (profondeur == 0)
{
return IA_Evaluation(grille, emplacements, colonne, emplacement, joueur);
}
if (check(grille, emplacements, colonne, emplacement, joueur) == 4)
{
if (joueur == 0)
{
return -1000;
}
return 1000;
}
if (GrillePleine(emplacements))
{
return 0;
}
for(i = 0; i < COLONNES && alpha < beta; i++)
{
// EFFICACITE: Balayer les colonnes du milieu vers l'extérieur (alternativement gauche/droite)
x += i*k;
k = -k;
if (emplacements[x] > -1)
{
y = InsererJeton(grille, emplacements, x, joueur);
alpha = max(alpha, -IA_NegaMaxAlphaBeta(profondeur-1, -beta, -alpha, grille, emplacements, x, y, joueur^1));
AnnulerJeton(grille, emplacements, y, x);
}
}
return alpha;
}
Is there something wrong in it ?
And here comes my negamax call:
int x = COLONNES/2, y, i, k = 1, scoreCoup, scoreMeilleur = -1000000, col = -1;
for(i = 0; i < COLONNES; i++)
{
// EFFICACITE: Balayer les colonnes du milieu vers l'extérieur (alternativement gauche/droite)
x += i*k;
k = -k;
if (emplacements[x] > -1)
{
y = InsererJeton(grille, emplacements, x, joueur);
scoreCoup = IA_NegaMaxAlphaBeta(4, -100000, 100000, grille, emplacements, colonne, emplacement, joueur);
if (scoreCoup > scoreMeilleur)
{
scoreMeilleur = scoreCoup;
col = x;
}
AnnulerJeton(grille, emplacements, y, x);
}
}
If you want to see my eval function, just ask. I don't show it right now because there are maybe errors in my negamax.
Oh and by the way... Sorry for my english if i made mistakes ! I'm from Belgium
Thanks in advance for your help !
