Fix Polyhedron.isempty()

[linpy.git] / pypol / linear.py

diff --git a/pypol/linear.py b/pypol/linear.py
index 8e96f35..5f3c559 100644 (file)
--- a/pypol/linear.py
+++ b/pypol/linear.py
@@ -72,15 +72,17 @@ class Expression:
         if not isinstance(constant, numbers.Rational):
             raise TypeError('constant must be a rational number')
         self._constant = constant
         if not isinstance(constant, numbers.Rational):
             raise TypeError('constant must be a rational number')
         self._constant = constant

+        self._symbols = tuple(sorted(self._coefficients))
+        self._dimension = len(self._symbols)

         return self
 
         return self
 

-
+    @property

     def symbols(self):
     def symbols(self):

-        yield from sorted(self._coefficients)
+        return self._symbols

 
     @property
     def dimension(self):
 
     @property
     def dimension(self):

-        return len(list(self.symbols()))
+        return self._dimension

 
     def coefficient(self, symbol):
         if isinstance(symbol, Expression) and symbol.issymbol():
 
     def coefficient(self, symbol):
         if isinstance(symbol, Expression) and symbol.issymbol():


@@ -94,9 +96,8 @@ class Expression:
 
     __getitem__ = coefficient
 
 
     __getitem__ = coefficient
 

-    @property

     def coefficients(self):
     def coefficients(self):

-        for symbol in self.symbols():
+        for symbol in self.symbols:

             yield symbol, self.coefficient(symbol)
 
     @property
             yield symbol, self.coefficient(symbol)
 
     @property


@@ -107,19 +108,20 @@ class Expression:
         return len(self._coefficients) == 0
 
     def values(self):
         return len(self._coefficients) == 0
 
     def values(self):

-        for symbol in self.symbols():
+        for symbol in self.symbols:

             yield self.coefficient(symbol)
         yield self.constant
 
     def values_int(self):
             yield self.coefficient(symbol)
         yield self.constant
 
     def values_int(self):

-        for symbol in self.symbols():
+        for symbol in self.symbols:

             return self.coefficient(symbol)
         return int(self.constant)
 
             return self.coefficient(symbol)
         return int(self.constant)
 

+    @property

     def symbol(self):
         if not self.issymbol():
             raise ValueError('not a symbol: {}'.format(self))
     def symbol(self):
         if not self.issymbol():
             raise ValueError('not a symbol: {}'.format(self))

-        for symbol in self.symbols():
+        for symbol in self.symbols:

             return symbol
 
     def issymbol(self):
             return symbol
 
     def issymbol(self):


@@ -136,8 +138,8 @@ class Expression:
 
     @_polymorphic_method
     def __add__(self, other):
 
     @_polymorphic_method
     def __add__(self, other):

-        coefficients = dict(self.coefficients)
-        for symbol, coefficient in other.coefficients:
+        coefficients = dict(self.coefficients())
+        for symbol, coefficient in other.coefficients():

             if symbol in coefficients:
                 coefficients[symbol] += coefficient
             else:
             if symbol in coefficients:
                 coefficients[symbol] += coefficient
             else:


@@ -149,8 +151,8 @@ class Expression:
 
     @_polymorphic_method
     def __sub__(self, other):
 
     @_polymorphic_method
     def __sub__(self, other):

-        coefficients = dict(self.coefficients)
-        for symbol, coefficient in other.coefficients:
+        coefficients = dict(self.coefficients())
+        for symbol, coefficient in other.coefficients():

             if symbol in coefficients:
                 coefficients[symbol] -= coefficient
             else:
             if symbol in coefficients:
                 coefficients[symbol] -= coefficient
             else:


@@ -164,7 +166,7 @@ class Expression:
     @_polymorphic_method
     def __mul__(self, other):
         if other.isconstant():
     @_polymorphic_method
     def __mul__(self, other):
         if other.isconstant():

-            coefficients = dict(self.coefficients)
+            coefficients = dict(self.coefficients())

             for symbol in coefficients:
                 coefficients[symbol] *= other.constant
             constant = self.constant * other.constant
             for symbol in coefficients:
                 coefficients[symbol] *= other.constant
             constant = self.constant * other.constant


@@ -202,7 +204,6 @@ class Expression:
 
     def __str__(self):
         string = ''
 
     def __str__(self):
         string = ''

-        symbols = sorted(self.symbols())

         i = 0
         for symbol in symbols:
             coefficient = self[symbol]
         i = 0
         for symbol in symbols:
             coefficient = self[symbol]


@@ -247,7 +248,7 @@ class Expression:
 
     def __repr__(self):
         string = '{}({{'.format(self.__class__.__name__)
 
     def __repr__(self):
         string = '{}({{'.format(self.__class__.__name__)

-        for i, (symbol, coefficient) in enumerate(self.coefficients):
+        for i, (symbol, coefficient) in enumerate(self.coefficients()):

             if i != 0:
                 string += ', '
             string += '{!r}: {!r}'.format(symbol, coefficient)
             if i != 0:
                 string += ', '
             string += '{!r}: {!r}'.format(symbol, coefficient)


@@ -269,30 +270,30 @@ class Expression:
     def __hash__(self):
         return hash((self._coefficients, self._constant))
 
     def __hash__(self):
         return hash((self._coefficients, self._constant))
 

-    def _canonify(self):
+    def _toint(self):

         lcm = functools.reduce(lambda a, b: a*b // gcd(a, b),
                 [value.denominator for value in self.values()])
         return self * lcm
 
     @_polymorphic_method
     def _eq(self, other):
         lcm = functools.reduce(lambda a, b: a*b // gcd(a, b),
                 [value.denominator for value in self.values()])
         return self * lcm
 
     @_polymorphic_method
     def _eq(self, other):

-        return Polyhedron(equalities=[(self - other)._canonify()])
+        return Polyhedron(equalities=[(self - other)._toint()])

 
     @_polymorphic_method
     def __le__(self, other):
 
     @_polymorphic_method
     def __le__(self, other):

-        return Polyhedron(inequalities=[(other - self)._canonify()])
+        return Polyhedron(inequalities=[(other - self)._toint()])

 
     @_polymorphic_method
     def __lt__(self, other):
 
     @_polymorphic_method
     def __lt__(self, other):

-        return Polyhedron(inequalities=[(other - self)._canonify() - 1])
+        return Polyhedron(inequalities=[(other - self)._toint() - 1])

 
     @_polymorphic_method
     def __ge__(self, other):
 
     @_polymorphic_method
     def __ge__(self, other):

-        return Polyhedron(inequalities=[(self - other)._canonify()])
+        return Polyhedron(inequalities=[(self - other)._toint()])

 
     @_polymorphic_method
     def __gt__(self, other):
 
     @_polymorphic_method
     def __gt__(self, other):

-        return Polyhedron(inequalities=[(self - other)._canonify() - 1])
+        return Polyhedron(inequalities=[(self - other)._toint() - 1])

 
 
 def constant(numerator=0, denominator=None):
 
 
 def constant(numerator=0, denominator=None):


@@ -352,6 +353,7 @@ class Polyhedron:
                         raise TypeError('non-integer constraint: '
                                 '{} == 0'.format(constraint))
                 self._equalities.append(constraint)
                         raise TypeError('non-integer constraint: '
                                 '{} == 0'.format(constraint))
                 self._equalities.append(constraint)

+        self._equalities = tuple(self._equalities)

         self._inequalities = []
         if inequalities is not None:
             for constraint in inequalities:
         self._inequalities = []
         if inequalities is not None:
             for constraint in inequalities:


@@ -360,46 +362,36 @@ class Polyhedron:
                         raise TypeError('non-integer constraint: '
                                 '{} <= 0'.format(constraint))
                 self._inequalities.append(constraint)
                         raise TypeError('non-integer constraint: '
                                 '{} <= 0'.format(constraint))
                 self._inequalities.append(constraint)

+        self._inequalities = tuple(self._inequalities)
+        self._constraints = self._equalities + self._inequalities
+        self._symbols = set()
+        for constraint in self._constraints:
+            self.symbols.update(constraint.symbols)
+        self._symbols = tuple(sorted(self._symbols))

         return self
 
     @property
     def equalities(self):
         return self
 
     @property
     def equalities(self):

-        yield from self._equalities
+        return self._equalities

 
     @property
     def inequalities(self):
 
     @property
     def inequalities(self):

-        yield from self._inequalities
+        return self._inequalities

 
     @property
 
     @property

-    def constant(self):
-        return self._constant
-
-    def isconstant(self):
-        return len(self._coefficients) == 0
-
-    def isempty(self):
-        return bool(libisl.isl_basic_set_is_empty(self._bset))
-

     def constraints(self):
     def constraints(self):

-        yield from self.equalities
-        yield from self.inequalities
+        return self._constraints

 
 

+    @property

     def symbols(self):
     def symbols(self):

-        s = set()
-        for constraint in self.constraints():
-            s.update(constraint.symbols())
-        return sorted(s)
+        return self._symbols

 
     @property
     def dimension(self):
 
     @property
     def dimension(self):

-        return len(self.symbols())
+        return len(self.symbols)

 
     def __bool__(self):
 
     def __bool__(self):

-        # return false if the polyhedron is empty, true otherwise
-        if self._equalities or self._inequalities:
-            return False
-        else:
-            return True
+        return not self.is_empty()

 
     def __contains__(self, value):
         # is the value in the polyhedron?
 
     def __contains__(self, value):
         # is the value in the polyhedron?


@@ -408,11 +400,12 @@ class Polyhedron:
     def __eq__(self, other):
         raise NotImplementedError
 
     def __eq__(self, other):
         raise NotImplementedError
 

-    def is_empty(self):
-        return
+    def isempty(self):
+        bset = self._to_isl()
+        return bool(libisl.isl_basic_set_is_empty(bset))

 
     def isuniverse(self):
 
     def isuniverse(self):

-        return self == universe
+        raise NotImplementedError

 
     def isdisjoint(self, other):
         # return true if the polyhedron has no elements in common with other
 
     def isdisjoint(self, other):
         # return true if the polyhedron has no elements in common with other


@@ -429,11 +422,6 @@ class Polyhedron:
 
     def issuperset(self, other):
         # test whether every element in other is in the polyhedron
 
     def issuperset(self, other):
         # test whether every element in other is in the polyhedron

-        for value in other:
-            if value == self.constraints():
-                return True
-            else:
-                return False

         raise NotImplementedError
 
     def __ge__(self, other):
         raise NotImplementedError
 
     def __ge__(self, other):


@@ -492,14 +480,14 @@ class Polyhedron:
         raise NotImplementedError
 
     def _symbolunion(self, *others):
         raise NotImplementedError
 
     def _symbolunion(self, *others):

-        symbols = set(self.symbols())
+        symbols = set(self.symbols)

         for other in others:
         for other in others:

-            symbols.update(other.symbols())
+            symbols.update(other.symbols)

         return sorted(symbols)
 
     def _to_isl(self, symbols=None):
         if symbols is None:
         return sorted(symbols)
 
     def _to_isl(self, symbols=None):
         if symbols is None:

-            symbols = self.symbols()
+            symbols = self.symbols

         num_coefficients = len(symbols)
         space = libisl.isl_space_set_alloc(_main_ctx, 0, num_coefficients)
         bset = libisl.isl_basic_set_universe(libisl.isl_space_copy(space))
         num_coefficients = len(symbols)
         space = libisl.isl_space_set_alloc(_main_ctx, 0, num_coefficients)
         bset = libisl.isl_basic_set_universe(libisl.isl_space_copy(space))


@@ -509,7 +497,7 @@ class Polyhedron:
         '''if there are equalities/inequalities, take each constant and coefficient and add as a constraint to the basic set'''
         if list(self.equalities): #check if any equalities exist
             for eq in self.equalities:
         '''if there are equalities/inequalities, take each constant and coefficient and add as a constraint to the basic set'''
         if list(self.equalities): #check if any equalities exist
             for eq in self.equalities:

-                coeff_eq = dict(eq.coefficients)
+                coeff_eq = dict(eq.coefficients())

                 if eq.constant:
                     value = eq.constant
                     ceq = libisl.isl_constraint_set_constant_si(ceq, value)
                 if eq.constant:
                     value = eq.constant
                     ceq = libisl.isl_constraint_set_constant_si(ceq, value)


@@ -520,7 +508,7 @@ class Polyhedron:
             bset = libisl.isl_basic_set_add_constraint(bset, ceq)
         if list(self.inequalities): #check if any inequalities exist
             for ineq in self.inequalities:
             bset = libisl.isl_basic_set_add_constraint(bset, ceq)
         if list(self.inequalities): #check if any inequalities exist
             for ineq in self.inequalities:

-                coeff_in = dict(ineq.coefficients)
+                coeff_in = dict(ineq.coefficients())

                 if ineq.constant:
                     value = ineq.constant
                     cin = libisl.isl_constraint_set_constant_si(cin, value)
                 if ineq.constant:
                     value = ineq.constant
                     cin = libisl.isl_constraint_set_constant_si(cin, value)


@@ -532,26 +520,34 @@ class Polyhedron:
         bset = isl.BasicSet(bset)
         return bset
 
         bset = isl.BasicSet(bset)
         return bset
 

-    def from_isl(self, bset):
+    @classmethod
+    def _from_isl(cls, bset):

         '''takes basic set in isl form and puts back into python version of polyhedron
         isl example code gives isl form as:
             "{[i] : exists (a : i = 2a and i >= 10 and i <= 42)}")
             our printer is giving form as:
             b'{ [i0] : 1 = 0 }' '''
         '''takes basic set in isl form and puts back into python version of polyhedron
         isl example code gives isl form as:
             "{[i] : exists (a : i = 2a and i >= 10 and i <= 42)}")
             our printer is giving form as:
             b'{ [i0] : 1 = 0 }' '''

+        raise NotImplementedError
+        equalities = ...
+        inequalities = ...
+        return cls(equalities, inequalities)

         #bset = self
         #bset = self

-        if self._equalities:
-            constraints = libisl.isl_basic_set_equalities_matrix(bset, 3)
-        elif self._inequalities:
-            constraints = libisl.isl_basic_set_inequalities_matrix(bset, 3)
-        print(constraints)
-        return constraints
+        # if self._equalities:
+        #     constraints = libisl.isl_basic_set_equalities_matrix(bset, 3)
+        # elif self._inequalities:
+        #     constraints = libisl.isl_basic_set_inequalities_matrix(bset, 3)
+        # print(constraints)
+        # return constraints

 
 empty = None #eq(0,1)
 universe = None #Polyhedron()
 
 
 empty = None #eq(0,1)
 universe = None #Polyhedron()
 

+

 if __name__ == '__main__':
     ex1 = Expression(coefficients={'a': 1, 'x': 2}, constant=2)
     ex2 = Expression(coefficients={'a': 3  , 'b': 2}, constant=3)
     p = Polyhedron(inequalities=[ex1, ex2])
     bs = p._to_isl()
     print(bs)
 if __name__ == '__main__':
     ex1 = Expression(coefficients={'a': 1, 'x': 2}, constant=2)
     ex2 = Expression(coefficients={'a': 3  , 'b': 2}, constant=3)
     p = Polyhedron(inequalities=[ex1, ex2])
     bs = p._to_isl()
     print(bs)

+    print('empty ?', p.isempty())
+    print('empty ?', eq(0, 1).isempty())