def __init__(self, name: str, first: MathExpr, last: MathExpr,
size: MathExpr) -> None:
first_num = first.simplified()
if not isinstance(first_num, Number):
raise ModelError(f'first of "{name}" contains variable')
last_num = last.simplified()
if not isinstance(last_num, Number):
raise ModelError(f'last of "{name}" contains variable')
if first_num < Number(0):
raise ModelError(f'first of "{name}" negative')
if first_num > last_num:
raise ModelError(f'range of "{name}" negative')
size_num = size.simplified()
if not isinstance(size_num, Number):
raise ModelError(f'size of "{name}" contains variable')
if log(int(last_num) + 1) / log(2) > int(size_num):
raise ModelError(f'size for "{name}" too small')
super().__init__(name)
self.__first = first
self.__last = last
self.__size = size
constraints: LogExpr = TRUE
if self.first.simplified() != self.base_first.simplified():
constraints = GreaterEqual(Value(self.name), self.first)
if self.last.simplified() != self.base_last.simplified():
constraints = And(constraints,
LessEqual(Value(self.name), self.last))
self.__constraints = constraints.simplified()
def constraints(self, name: str, proof: bool = False) -> Expr:
if proof:
return And(
GreaterEqual(Variable(name), self.first), LessEqual(Variable(name), self.last)
)
c: Expr = TRUE
if self.first.simplified() != self.base_first.simplified():
c = GreaterEqual(Variable(name), self.first)
if self.last.simplified() != self.base_last.simplified():
c = And(c, LessEqual(Variable(name), self.last))
return c.simplified()