forbid to leave the goal state

main.py

@@ -92,6 +92,16 @@ def init_global(maze_filename):
                 PW_OF_X_U[ix, iu, -1] = 1 - PW_OF_X_U[ix, iu].sum()
                 F_X_U_W[ix, iu, -1] = ij_to_s[tuple(x + u)]
 
+    # Forbid to leave the goal state
+    # (could've been done through cost function though)
+    goal_idx = ij_to_s[np.where(MAZE == b'G')][0]
+    U_OF_X[goal_idx] = False
+    U_OF_X[goal_idx, -1] = True
+    PW_OF_X_U[goal_idx] = 0
+    PW_OF_X_U[goal_idx, -1, -1] = 1
+    F_X_U_W[goal_idx] = 0
+    F_X_U_W[goal_idx, -1, -1] = goal_idx
+
 
 def h_matrix(j, g):
     h_x_u = (PW_OF_X_U * (g[F_X_U_W] + ALPHA*j[F_X_U_W])).sum(axis=2)