Constraint Precedence

__init__.py

@@ -14,8 +14,8 @@
 from pycsp3.functions import variant, subvariant, Var, VarArray, satisfy, minimize, maximize, annotate
 from pycsp3.functions import And, Or, Not, Xor, IfThen, IfThenElse, Iff, Slide
 from pycsp3.functions import protect, col, abs, min, max, xor, iff, imply, ift, expr, conjunction, disjunction
-from pycsp3.functions import (AllDifferent, AllDifferentList, AllEqual, Increasing, Decreasing, LexIncreasing, LexDecreasing, Sum, Count, NValues, Cardinality,
-                              Maximum, Minimum, Channel, NoOverlap, Cumulative, BinPacking, Circuit, Clause)
+from pycsp3.functions import (AllDifferent, AllDifferentList, AllEqual, Increasing, Decreasing, LexIncreasing, LexDecreasing, Precedence, Sum, Count, NValues,
+                              Cardinality, Maximum, Minimum, Channel, NoOverlap, Cumulative, BinPacking, Circuit, Clause)
 from pycsp3.functions import posted, objective, unpost, value, values
 
 from pycsp3.tools.curser import columns, diagonal_down, diagonals_down, diagonal_up, diagonals_up, cp_array
@@ -49,7 +49,6 @@
 CHOCO = TypeSolver.CHOCO
 """ Solver Choco """
 
-
 if sys.argv:
     if len(sys.argv) == 1 and sys.argv[0] == "-m":  # copy of models
         import shutil
@@ -188,7 +187,7 @@ def solve(*, solver=ACE, options="", filename=None, verbose=-1, sols=None, extra
             if sols == ALL or isinstance(sols, int) and sols > 1:
                 options += " -xe -xc=false"
         elif solver == CHOCO:
-            #options += " -v=" + str(verbose)
+            # options += " -v=" + str(verbose)
             if sols == ALL or isinstance(sols, int) and sols > 1:
                 options += " -a "
         _solver.setting(options)

classes/auxiliary/ptypes.py

@@ -84,6 +84,7 @@ class TypeCtrArg(AbstractType):
     SIZES, WEIGTHS, PROFITS = auto(3)
     SIZE, ROOT, IMAGE, GRAPH, ROW, EXPRESSION, TYPE = auto(7)
     START_INDEX, START_ROW_INDEX, START_COL_INDEX = auto(3)
+    COVERED = auto()
 
 
 @unique
@@ -206,4 +207,4 @@ class TypeStatus(Enum):
     UNSAT, SAT, OPTIMUM, CORE, UNKNOWN = auto(5)
 
     def __str__(self):
-        return self.name
+        return self.name

classes/main/constraints.py

@@ -390,6 +390,13 @@ def __init__(self, lst, operator):
         self.arg(TypeCtrArg.OPERATOR, operator)
 
 
+class ConstraintPrecedence(Constraint):
+    def __init__(self, lst, values, covered=False):
+        super().__init__(TypeCtr.PRECEDENCE)
+        self.arg(TypeCtrArg.LIST, lst, content_ordered=True)
+        self.arg(TypeCtrArg.VALUES, values, attributes=[(TypeCtrArg.COVERED, "true")] if covered else [], content_ordered=True)
+
+
 ''' Counting and Summing Constraints '''
 
 

functions.py

@@ -13,8 +13,8 @@
     AnnotationRestarts)
 from pycsp3.classes.main.constraints import (
     ConstraintIntension, ConstraintExtension, ConstraintRegular, ConstraintMdd, ConstraintAllDifferent,
-    ConstraintAllDifferentList, ConstraintAllDifferentMatrix, ConstraintAllEqual, ConstraintOrdered, ConstraintLex, ConstraintLexMatrix, ConstraintSum,
-    ConstraintCount, ConstraintNValues, ConstraintCardinality, ConstraintMaximum, ConstraintMinimum, ConstraintChannel, ConstraintNoOverlap,
+    ConstraintAllDifferentList, ConstraintAllDifferentMatrix, ConstraintAllEqual, ConstraintOrdered, ConstraintLex, ConstraintLexMatrix, ConstraintPrecedence,
+    ConstraintSum, ConstraintCount, ConstraintNValues, ConstraintCardinality, ConstraintMaximum, ConstraintMinimum, ConstraintChannel, ConstraintNoOverlap,
     ConstraintCumulative, ConstraintBinPacking, ConstraintCircuit, ConstraintClause, PartialConstraint, ScalarProduct, auxiliary, manage_global_indirection)
 from pycsp3.classes.main.domains import Domain
 from pycsp3.classes.main.objectives import ObjectiveExpression, ObjectivePartial
@@ -767,6 +767,18 @@ def LexDecreasing(term, *others, strict=False, matrix=False):
     return _lex(term, others, TypeOrderedOperator.DECREASING if not strict else TypeOrderedOperator.STRICTLY_DECREASING, matrix)
 
 
+def Precedence(scope, *, values, covered=False):
+    """
+    Builds and returns a constraint Precedence.
+
+    :param scope: the scope of the constraint
+    :param values: the values such that the ith value must precede the i+1th value in the scope
+    :param covered: if True, all specified values must be assigned to the variables of the scope
+    :return: a constraint Precedence
+    """
+    return ECtr(ConstraintPrecedence(scope, values, covered))
+
+
 ''' Method for handling complete/partial constraints '''