fix BIBD model

nucs/examples/bibd/__main__.py

@@ -6,6 +6,8 @@
 
 if __name__ == "__main__":
     problem = BIBDProblem(8, 14, 7, 4, 3)
+    # problem = BIBDProblem(6, 10, 5, 3, 2)
+    # problem = BIBDProblem(7, 7, 3, 3, 1)
     solver = BacktrackSolver(problem)
-    solver.solve_all()
-    print(get_statistics(solver.statistics))
+    solver.solve_all(lambda solution: print(problem.solution_as_matrix(solution)))
+    print(get_statistics(solver.statistics))

nucs/examples/bibd/bibd_problem.py

@@ -1,3 +1,5 @@
+from typing import List
+
 from nucs.problems.problem import Problem
 from nucs.propagators.propagators import ALG_EXACTLY_EQ, ALG_LEXICOGRAPHIC_LEQ, ALG_MIN_EQ
 
@@ -7,32 +9,50 @@ class BIBDProblem(Problem):
     CSPLIB problem #28 - https://www.csplib.org/Problems/prob028/
     """
 
-    def __init__(self, v: int, b: int, r: int, k: int, l: int):
-        s = (v * (v - 1)) // 2
-        n = (v + s) * b
-        super().__init__([(0, 1)] * n)
+    def __init__(self, object_nb: int, block_nb: int, by_row_count: int, by_column_count: int, scalar_product: int):
+        self.object_nb = object_nb  # number of rows
+        self.block_nb = block_nb  # number of columns
+        matrix_var_nb = object_nb * block_nb  # number of cells in the matrix
+        redundant_var_nb = ((object_nb * (object_nb - 1)) // 2) * block_nb
+        super().__init__([(0, 1)] * (matrix_var_nb + redundant_var_nb))
         # rows: counts
-        for i in range(0, v):
-            self.add_propagator((list(range(i * b, (i + 1) * b)), ALG_EXACTLY_EQ, [1, r]))
+        for object_idx in range(0, object_nb):
+            self.add_propagator(
+                (list(range(object_idx * block_nb, (object_idx + 1) * block_nb)), ALG_EXACTLY_EQ, [1, by_row_count])
+            )
         # columns: counts
-        for j in range(0, b):
-            self.add_propagator((list(range(j, v * b, b)), ALG_EXACTLY_EQ, [1, k]))
+        for block_idx in range(0, block_nb):
+            self.add_propagator(
+                (list(range(block_idx, object_nb * block_nb, block_nb)), ALG_EXACTLY_EQ, [1, by_column_count])
+            )
         # scalar products: conjunctions and counts
-        conj_idx = v * b
-        for i1 in range(0, v - 1):
-            for i2 in range(i1 + 1, v):
+        conj_idx = object_nb * block_nb  # index of first redundant variable
+        for i1 in range(0, object_nb - 1):
+            for i2 in range(i1 + 1, object_nb):
                 conj_vars = []
-                for j in range(0, b):
+                for block_idx in range(0, block_nb):
                     self.add_propagator(
-                        ([(i1 * b + j), (i2 * b + j), conj_idx], ALG_MIN_EQ, [])
+                        ([(i1 * block_nb + block_idx), (i2 * block_nb + block_idx), conj_idx], ALG_MIN_EQ, [])
                     )  # TODO:replace by AND ?
                     conj_vars.append(conj_idx)
                     conj_idx += 1
-                self.add_propagator((conj_vars, ALG_EXACTLY_EQ, [1, l]))
+                self.add_propagator((conj_vars, ALG_EXACTLY_EQ, [1, scalar_product]))
         # remove symmetries
         # lexleq on rows
-        for i in range(0, v - 1):
-            self.add_propagator((list(range(i * b, (i + 2) * b)), ALG_LEXICOGRAPHIC_LEQ, []))
+        for object_idx in range(0, object_nb - 1):
+            self.add_propagator(
+                (list(range(object_idx * block_nb, (object_idx + 2) * block_nb)), ALG_LEXICOGRAPHIC_LEQ, [])
+            )
         # lexleq on columns
-        for j in range(0, b - 1):
-            self.add_propagator((list(range(j, v * b, b)) + list(range(j + 1, v * b, b)), ALG_LEXICOGRAPHIC_LEQ, []))
+        for block_idx in range(0, block_nb - 1):
+            self.add_propagator(
+                (
+                    list(range(block_idx, object_nb * block_nb, block_nb))
+                    + list(range(block_idx + 1, object_nb * block_nb, block_nb)),
+                    ALG_LEXICOGRAPHIC_LEQ,
+                    [],
+                )
+            )
+
+    def solution_as_matrix(self, solution: List[int]) -> List[List[int]]:
+        return [[solution[i * self.block_nb + j] for j in range(0, self.block_nb)] for i in range(0, self.object_nb)]

tests/examples/test_bibd.py

@@ -10,8 +10,16 @@ def test_6_10_5_3_2(self) -> None:
         solver.solve_all()
         assert solver.statistics[STATS_SOLVER_SOLUTION_NB] == 1
 
+    def test_7_7_3_3_1(self) -> None:
+        problem = BIBDProblem(7, 7, 3, 3, 1)
+        solver = BacktrackSolver(problem)
+        solver.solve_all()
+        assert solver.statistics[STATS_SOLVER_SOLUTION_NB] == 1
+
     def test_8_14_7_4_3(self) -> None:
         problem = BIBDProblem(8, 14, 7, 4, 3)
         solver = BacktrackSolver(problem)
         solver.solve_all()
         assert solver.statistics[STATS_SOLVER_SOLUTION_NB] == 92
+
+