class Domain(GeometricObject):
"""
A domain is a union of polyhedra. Unlike polyhedra, domains allow exact
- computation of union and complementary operations.
+ computation of union, subtraction and complementary operations.
A domain with a unique polyhedron is automatically subclassed as a
Polyhedron instance.
Create a domain from a string. Raise SyntaxError if the string is not
properly formatted.
"""
- # remove curly brackets
+ # Remove curly brackets.
string = cls._RE_BRACES.sub(r'', string)
- # replace '=' by '=='
+ # Replace '=' by '=='.
string = cls._RE_EQ.sub(r'\1==\2', string)
- # replace 'and', 'or', 'not'
+ # Replace 'and', 'or', 'not'.
string = cls._RE_AND.sub(r' & ', string)
string = cls._RE_OR.sub(r' | ', string)
string = cls._RE_NOT.sub(r' ~', string)
- # add implicit multiplication operators, e.g. '5x' -> '5*x'
+ # Add implicit multiplication operators, e.g. '5x' -> '5*x'.
string = cls._RE_NUM_VAR.sub(r'\1*\2', string)
- # add parentheses to force precedence
+ # Add parentheses to force precedence.
tokens = cls._RE_OPERATORS.split(string)
for i, token in enumerate(tokens):
if i % 2 == 0:
@classmethod
def fromsympy(cls, expr):
"""
- Create a domain from a sympy expression.
+ Create a domain from a SymPy expression.
"""
import sympy
from .polyhedra import Lt, Le, Eq, Ne, Ge, Gt
def tosympy(self):
"""
- Convert the domain to a sympy expression.
+ Convert the domain to a SymPy expression.
"""
import sympy
polyhedra = [polyhedron.tosympy() for polyhedron in polyhedra]
return Universe
else:
return domains[0].intersection(*domains[1:])
-And.__doc__ = Domain.intersection.__doc__
def Or(*domains):
"""
return Empty
else:
return domains[0].union(*domains[1:])
-Or.__doc__ = Domain.union.__doc__
def Not(domain):
"""
Create the complementary domain of the domain given in argument.
"""
return ~domain
-Not.__doc__ = Domain.complement.__doc__