nqueens (handcrafted B for now)

Author: Dimosts

pycona/benchmarks/nqueens.py

@@ -16,26 +16,29 @@ def construct_nqueens_problem(n):
 
     # Constraints list
     CT = []
+    diag = []
 
     CT += list(cp.AllDifferent(queens).decompose())
 
     for i in range(n):
         for j in range(i + 1, n): # Compare each queen with every other queen once
-            CT += [(queens[i] - i != queens[j] - j)]  # Different major diagonals
-            CT += [(queens[i] + i != queens[j] + j)]  # Different minor diagonals
-
+            diag += [(queens[i] - i != queens[j] - j)]  # Different major diagonals
+            diag += [(queens[i] + i != queens[j] + j)]  # Different minor diagonals
 
     # Add all collected constraints to the model
-    model += CT
+    model += CT + diag
 
-    C_T = toplevel_list(CT) 
+    C_T = toplevel_list(CT + diag) 
 
     AV = absvar(2)
-    #lang = [AV[0] == AV[1], AV[0] != AV[1], AV[0] < AV[1], AV[0] > AV[1], AV[0] >= AV[1], AV[0] <= AV[1]] + 
-    lang = [AV[0] - AV[1] == constant for constant in range(-n, 2*n)] + [AV[0] - AV[1] != constant for constant in range(-n, 2*n)]
+    lang = [AV[0] == AV[1], AV[0] != AV[1], AV[0] < AV[1], AV[0] > AV[1], AV[0] >= AV[1], AV[0] <= AV[1]]
+    #lang = [AV[0] - AV[1] == constant for constant in range(-n, 2*n)] + [AV[0] - AV[1] != constant for constant in range(-n, 2*n)]
 
     instance = ProblemInstance(variables=queens, params=parameters, language=lang, name="nqueens")
 
+    instance.construct_bias()
+    instance.bias = instance.bias + diag
+
     oracle = ConstraintOracle(list(set(toplevel_list(C_T))))
 
     print("oracle constraints: ", len(oracle.constraints))