from fractions import Fraction, gcd
-from . import isl, islhelper
-from .isl import libisl, Context, BasicSet
+from . import isl
+from .isl import libisl
__all__ = [
return wrapper
+_main_ctx = isl.Context()
+
+
class Expression:
"""
This class implements linear expressions.
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
-
+ @property
def symbols(self):
- yield from sorted(self._coefficients)
+ return self._symbols
@property
def dimension(self):
- return len(list(self.symbols()))
+ return self._dimension
def coefficient(self, symbol):
if isinstance(symbol, Expression) and symbol.issymbol():
__getitem__ = coefficient
- @property
def coefficients(self):
- for symbol in self.symbols():
+ for symbol in self.symbols:
yield symbol, self.coefficient(symbol)
@property
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):
- for symbol in self.symbols():
+ for symbol in self.symbols:
return self.coefficient(symbol)
return int(self.constant)
+ @property
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):
@_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:
@_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:
@_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
def __str__(self):
string = ''
- symbols = sorted(self.symbols())
i = 0
for symbol in symbols:
coefficient = self[symbol]
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)
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):
- return Polyhedron(equalities=[(self - other)._canonify()])
+ return Polyhedron(equalities=[(self - other)._toint()])
@_polymorphic_method
def __le__(self, other):
- return Polyhedron(inequalities=[(other - self)._canonify()])
+ return Polyhedron(inequalities=[(other - self)._toint()])
@_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):
- return Polyhedron(inequalities=[(self - other)._canonify()])
+ return Polyhedron(inequalities=[(self - other)._toint()])
@_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):
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:
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):
- yield from self._equalities
+ return self._equalities
@property
def inequalities(self):
- yield from self._inequalities
+ return self._inequalities
@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):
- yield from self.equalities
- yield from self.inequalities
+ return self._constraints
+ @property
def symbols(self):
- s = set()
- for constraint in self.constraints():
- s.update(constraint.symbols())
- return sorted(s)
+ return self._symbols
@property
def dimension(self):
- return len(self.symbols())
+ return len(self.symbols)
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 __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):
- return self == universe
+ raise NotImplementedError
def isdisjoint(self, other):
# return true if the polyhedron has no elements in common with other
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 _symbolunion(self, *others):
- symbols = set(self.symbols())
+ symbols = set(self.symbols)
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:
- symbols = self.symbols()
+ symbols = self.symbols
num_coefficients = len(symbols)
- ctx = Context()
- space = libisl.isl_space_set_alloc(ctx, 0, num_coefficients)
+ space = libisl.isl_space_set_alloc(_main_ctx, 0, num_coefficients)
bset = libisl.isl_basic_set_universe(libisl.isl_space_copy(space))
ls = libisl.isl_local_space_from_space(space)
ceq = libisl.isl_equality_alloc(libisl.isl_local_space_copy(ls))
'''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)
for eq in coeff_eq:
num = coeff_eq.get(eq)
iden = symbols.index(eq)
- ceq = libisl.isl_constraint_set_coefficient_si(ceq, islhelper.isl_dim_set, iden, num) #use 3 for type isl_dim_set
+ ceq = libisl.isl_constraint_set_coefficient_si(ceq, libisl.isl_dim_set, iden, num) #use 3 for type isl_dim_set
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)
for ineq in coeff_in:
num = coeff_in.get(ineq)
iden = symbols.index(ineq)
- cin = libisl.isl_constraint_set_coefficient_si(cin, islhelper.isl_dim_set, iden, num) #use 3 for type isl_dim_set
+ cin = libisl.isl_constraint_set_coefficient_si(cin, libisl.isl_dim_set, iden, num) #use 3 for type isl_dim_set
bset = libisl.isl_basic_set_add_constraint(bset, cin)
- bset = BasicSet(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 }' '''
+ raise NotImplementedError
+ equalities = ...
+ inequalities = ...
+ return cls(equalities, inequalities)
#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()
+
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())
projects / linpy.git / blobdiff