-
import functools
import numbers
+import ctypes, ctypes.util
+from pypol import isl
from fractions import Fraction, gcd
+libisl = ctypes.CDLL(ctypes.util.find_library('isl'))
+
+libisl.isl_printer_get_str.restype = ctypes.c_char_p
__all__ = [
'Expression',
]
+_CONTEXT = isl.Context()
+
+def _polymorphic_method(func):
+ @functools.wraps(func)
+ def wrapper(a, b):
+ if isinstance(b, Expression):
+ return func(a, b)
+ if isinstance(b, numbers.Rational):
+ b = constant(b)
+ return func(a, b)
+ return NotImplemented
+ return wrapper
+
+def _polymorphic_operator(func):
+ # A polymorphic operator should call a polymorphic method, hence we just
+ # have to test the left operand.
+ @functools.wraps(func)
+ def wrapper(a, b):
+ if isinstance(a, numbers.Rational):
+ a = constant(a)
+ return func(a, b)
+ elif isinstance(a, Expression):
+ return func(a, b)
+ raise TypeError('arguments must be linear expressions')
+ return wrapper
+
+
class Expression:
"""
This class implements linear expressions.
self._constant = constant
return self
+
def symbols(self):
yield from sorted(self._coefficients)
yield self.coefficient(symbol)
yield self.constant
+ def values_int(self):
+ for symbol in self.symbols():
+ return self.coefficient(symbol)
+ return int(self.constant)
+
+
def symbol(self):
if not self.issymbol():
raise ValueError('not a symbol: {}'.format(self))
def __neg__(self):
return self * -1
- def _polymorphic(func):
- @functools.wraps(func)
- def wrapper(self, other):
- if isinstance(other, Expression):
- return func(self, other)
- if isinstance(other, numbers.Rational):
- other = Expression(constant=other)
- return func(self, other)
- return NotImplemented
- return wrapper
-
- @_polymorphic
+ @_polymorphic_method
def __add__(self, other):
coefficients = dict(self.coefficients())
for symbol, coefficient in other.coefficients():
__radd__ = __add__
- @_polymorphic
+ @_polymorphic_method
def __sub__(self, other):
coefficients = dict(self.coefficients())
for symbol, coefficient in other.coefficients():
constant = self.constant - other.constant
return Expression(coefficients, constant)
- __rsub__ = __sub__
-
- @_polymorphic
+ def __rsub__(self, other):
+ return -(self - other)
+
+ @_polymorphic_method
def __mul__(self, other):
if other.isconstant():
coefficients = dict(self.coefficients())
__rmul__ = __mul__
- @_polymorphic
+ @_polymorphic_method
def __truediv__(self, other):
if other.isconstant():
coefficients = dict(self.coefficients())
return NotImplemented
def __rtruediv__(self, other):
- if isinstance(other, Rational):
+ if isinstance(other, self):
if self.isconstant():
constant = Fraction(other, self.constant)
return Expression(constant=constant)
elif constant < 0:
constant *= -1
string += ' - {}'.format(constant)
+ if string == '':
+ string = '0'
return string
def _parenstr(self, always=False):
def fromstring(cls, string):
raise NotImplementedError
- @_polymorphic
+ @_polymorphic_method
def __eq__(self, other):
# "normal" equality
# see http://docs.sympy.org/dev/tutorial/gotchas.html#equals-signs
[value.denominator for value in self.values()])
return self * lcm
- @_polymorphic
+ @_polymorphic_method
def _eq(self, other):
return Polyhedron(equalities=[(self - other)._canonify()])
- @_polymorphic
+ @_polymorphic_method
def __le__(self, other):
return Polyhedron(inequalities=[(self - other)._canonify()])
- @_polymorphic
+ @_polymorphic_method
def __lt__(self, other):
return Polyhedron(inequalities=[(self - other)._canonify() + 1])
- @_polymorphic
+ @_polymorphic_method
def __ge__(self, other):
return Polyhedron(inequalities=[(other - self)._canonify()])
- @_polymorphic
+ @_polymorphic_method
def __gt__(self, other):
return Polyhedron(inequalities=[(other - self)._canonify() + 1])
def constant(numerator=0, denominator=None):
- return Expression(constant=Fraction(numerator, denominator))
+ if denominator is None and isinstance(numerator, numbers.Rational):
+ return Expression(constant=3)
+ else:
+ return Expression(constant=Fraction(numerator, denominator))
def symbol(name):
if not isinstance(name, str):
return (symbol(name) for name in names)
-def _operator(func):
- @functools.wraps(func)
- def wrapper(a, b):
- if isinstance(a, numbers.Rational):
- a = constant(a)
- if isinstance(b, numbers.Rational):
- b = constant(b)
- if isinstance(a, Expression) and isinstance(b, Expression):
- return func(a, b)
- raise TypeError('arguments must be linear expressions')
- return wrapper
-
-@_operator
+@_polymorphic_operator
def eq(a, b):
return a._eq(b)
-@_operator
+@_polymorphic_operator
def le(a, b):
return a <= b
-@_operator
+@_polymorphic_operator
def lt(a, b):
return a < b
-@_operator
+@_polymorphic_operator
def ge(a, b):
return a >= b
-@_operator
+@_polymorphic_operator
def gt(a, b):
return a > b
if value.denominator != 1:
raise TypeError('non-integer constraint: '
'{} <= 0'.format(constraint))
- self._inequalities.append(constraint)
- return self
-
+ self._inequalities.append(constraint)
+ self._bset = self.to_isl()
+ return self._bset
+
+
@property
def equalities(self):
yield from self._equalities
@property
def inequalities(self):
yield from 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
+
def symbols(self):
s = set()
for constraint in self.constraints():
s.update(constraint.symbols)
- yield from sorted(s)
-
+ yield from sorted(s)
+
+ def symbol_count(self):
+ s = []
+ for constraint in self.constraints():
+ s.append(constraint.symbols)
+ return s
+
@property
def dimension(self):
return len(self.symbols())
def __bool__(self):
# return false if the polyhedron is empty, true otherwise
- raise NotImplementedError
+ if self._equalities or self._inequalities:
+ return False
+ else:
+ return True
+
def __contains__(self, value):
# is the value in the polyhedron?
def __eq__(self, other):
raise NotImplementedError
- def isempty(self):
- return self == empty
+ def is_empty(self):
+ return
def isuniverse(self):
return self == universe
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):
@classmethod
def fromstring(cls, string):
raise NotImplementedError
+
+ def to_isl(self):
+ space = libisl.isl_space_set_alloc(_CONTEXT, 0, len(self.symbol_count()))
+ bset = libisl.isl_basic_set_empty(libisl.isl_space_copy(space))
+ ls = libisl.isl_local_space_from_space(libisl.isl_space_copy(space))
+ ceq = libisl.isl_equality_alloc(libisl.isl_local_space_copy(ls))
+ cin = libisl.isl_inequality_alloc(libisl.isl_local_space_copy(ls))
+ d = Expression().__dict__ #write expression values to dictionary in form {'_constant': value, '_coefficients': value}
+ '''
+ if there are equalities/inequalities, take each constant and coefficient and add as a constraint to the basic set
+ need to change the symbols method to a lookup table for the integer value for each letter that could be a symbol
+ '''
+ if self._equalities:
+ if '_constant' in d:
+ value = d.get('_constant')
+ ceq = libisl.isl_constraint_set_constant_si(ceq, value)
+ if '_coefficients' in d:
+ value_co = d.get('_coefficients')
+ if value_co: #if dictionary not empty add coefficient as to constraint
+ ceq = libisl.isl_constraint_set_coefficient_si(ceq, libisl.isl_set_dim, self.symbols(), value_co)
+ bset = libisl.isl_set_add_constraint(bset, ceq)
+
+ if self._inequalities:
+ if '_constant' in d:
+ value = d.get('_constant')
+ cin = libisl.isl_constraint_set_constant_si(cin, value)
+ if '_coefficients' in d:
+ value_co = d.get('_coefficients')
+ if value_co: #if dictionary not empty add coefficient as to constraint
+ cin = libisl.isl_constraint_set_coefficient_si(cin, libisl.isl_set_dim, self.symbols(), value_co)
+ bset = libisl.isl_set_add_constraint(bset, cin)
+ ip = libisl.isl_printer_to_str(_CONTEXT) #create string printer
+ ip = libisl.isl_printer_print_set(ip, bset) #print set to printer
+ string = libisl.isl_printer_get_str(ip) #get string from printer
+ print(string)
+ return bset
+
+empty = eq(1, 1)
-empty = le(1, 0)
-
universe = Polyhedron()
projects / linpy.git / blobdiff