add latin squares and unique sudoku instance name

Author: Dimosts

pycona/benchmarks/__init__.py

@@ -6,4 +6,5 @@
 from .nurse_rostering import construct_nurse_rostering
 from .zebra import construct_zebra_problem
 from .nqueens import construct_nqueens_problem
-from .golomb import construct_golomb
+from .golomb import construct_golomb
+from .latin_squares import construct_latin_squares

pycona/benchmarks/latin_squares.py

@@ -0,0 +1,39 @@
+import cpmpy as cp
+from cpmpy.transformations.normalize import toplevel_list
+from ..answering_queries.constraint_oracle import ConstraintOracle
+from ..problem_instance import ProblemInstance, absvar
+
+
+def construct_latin_squares(grid_size=4):
+    """
+    :return: a ProblemInstance object, along with a constraint-based oracle
+    """
+
+    # Create a dictionary with the parameters
+    parameters = {"grid_size": grid_size}
+
+    # Variables
+    grid = cp.intvar(1, grid_size, shape=(grid_size, grid_size), name="grid")
+
+    model = cp.Model()
+
+    # Constraints on rows and columns
+    for row in grid:
+        model += cp.AllDifferent(row).decompose()
+
+    for col in grid.T:  # numpy's Transpose
+        model += cp.AllDifferent(col).decompose()
+
+    C_T = list(set(toplevel_list(model.constraints)))
+
+    # Create the language:
+    AV = absvar(2)  # create abstract vars - as many as maximum arity
+
+    # create abstract relations using the abstract vars
+    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]]
+
+    instance = ProblemInstance(variables=grid, params=parameters, language=lang, name=f"latin_squares_{grid_size}")
+
+    oracle = ConstraintOracle(C_T)
+
+    return instance, oracle

pycona/benchmarks/sudoku.py

@@ -37,7 +37,7 @@ def construct_sudoku(block_size_row=2, block_size_col=2, grid_size=4):
     # create abstract relations using the abstract vars
     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]]
 
-    instance = ProblemInstance(variables=grid, params=parameters, language=lang, name="sudoku")
+    instance = ProblemInstance(variables=grid, params=parameters, language=lang, name=f"sudoku_{block_size_row}_{block_size_col}_{grid_size}")
 
     oracle = ConstraintOracle(C_T)