def test_potentially_variable(self):
p = parameter()
self.assertEqual(p.is_potentially_variable(), False)
self.assertEqual(potentially_variable(p), False)
p.value = 1.0
self.assertEqual(p.is_potentially_variable(), False)
self.assertEqual(potentially_variable(p), False)
def test_potentially_variable(self):
v = variable()
self.assertEqual(v.is_potentially_variable(), True)
self.assertEqual(potentially_variable(v), True)
self.assertEqual(v.fixed, False)
self.assertEqual(v.value, None)
v.value = 1.0
self.assertEqual(v.is_potentially_variable(), True)
self.assertEqual(potentially_variable(v), True)
self.assertEqual(v.fixed, False)
self.assertEqual(v.value, 1.0)
v.fix()
self.assertEqual(v.is_potentially_variable(), True)
self.assertEqual(potentially_variable(v), True)
self.assertEqual(v.fixed, True)
self.assertEqual(v.value, 1.0)
v.value = None
self.assertEqual(v.is_potentially_variable(), True)
self.assertEqual(potentially_variable(v), True)
self.assertEqual(v.fixed, True)
self.assertEqual(v.value, None)
v.free()
self.assertEqual(v.is_potentially_variable(), True)
self.assertEqual(potentially_variable(v), True)
self.assertEqual(v.fixed, False)
self.assertEqual(v.value, None)
def testis_potentially_variable(self):
e = noclone(variable())
self.assertEqual(e.is_potentially_variable(), True)
self.assertEqual(potentially_variable(e), True)
e = noclone(parameter())
self.assertEqual(e.is_potentially_variable(), False)
self.assertEqual(potentially_variable(e), False)
e = noclone(expression())
self.assertEqual(e.is_potentially_variable(), True)
self.assertEqual(potentially_variable(e), True)
e = noclone(data_expression())
self.assertEqual(e.is_potentially_variable(), False)
self.assertEqual(potentially_variable(e), False)
def testis_potentially_variable(self):
e = self._ctype_factory()
self.assertEqual(e.is_potentially_variable(), True)
self.assertEqual(potentially_variable(e), True)
e.expr = 1
self.assertEqual(e.is_potentially_variable(), True)
self.assertEqual(potentially_variable(e), True)
v = variable()
v.value = 2
e.expr = v + 1
self.assertEqual(e.is_potentially_variable(), True)
self.assertEqual(potentially_variable(e), True)
v.fix()
e.expr = v + 1
self.assertEqual(e.is_potentially_variable(), True)
self.assertEqual(potentially_variable(e), True)
self.assertEqual(e(), 3)
def testis_potentially_variable(self):
e = self._ctype_factory()
self.assertEqual(e.is_potentially_variable(), False)
self.assertEqual(potentially_variable(e), False)
e.expr = 1
self.assertEqual(e.is_potentially_variable(), False)
self.assertEqual(potentially_variable(e), False)
p = parameter()
e.expr = p**2
self.assertEqual(e.is_potentially_variable(), False)
self.assertEqual(potentially_variable(e), False)
a = self._ctype_factory()
e.expr = (a * p)**2 / (p + 5)
self.assertEqual(e.is_potentially_variable(), False)
self.assertEqual(potentially_variable(e), False)
a.expr = 2.0
p.value = 5.0
self.assertEqual(e.is_potentially_variable(), False)
self.assertEqual(potentially_variable(e), False)
self.assertEqual(e(), 10.0)
v = variable()
with self.assertRaises(ValueError):
e.expr = v + 1
def __init__(self, variables, weights=None, level=1):
self._parent = None
self._active = True
self._variables = tuple(variables)
self._weights = None
self._level = level
if weights is None:
self._weights = tuple(range(1, len(self._variables) + 1))
else:
self._weights = tuple(weights)
for w in self._weights:
if potentially_variable(w):
raise ValueError(
"Weights for Special Ordered Sets must be "
"expressions restricted to data")
assert len(self._variables) == len(self._weights)
assert self._level >= 1
def expr(self, expr):
self._equality = False
if expr is None:
self.body = None
self.lb = None
self.ub = None
return
_expr_type = expr.__class__
if _expr_type is tuple:
#
# Form equality expression
#
if len(expr) == 2:
arg0 = expr[0]
if arg0 is not None:
arg0 = as_numeric(arg0)
arg1 = expr[1]
if arg1 is not None:
arg1 = as_numeric(arg1)
# assigning to the rhs property
# will set the equality flag to True
if (arg1 is None) or (not arg1.is_potentially_variable()):
self.rhs = arg1
self.body = arg0
elif (arg0 is None) or (not arg0.is_potentially_variable()):
self.rhs = arg0
self.body = arg1
else:
self.rhs = ZeroConstant
self.body = arg0
self.body -= arg1
#
# Form inequality expression
#
elif len(expr) == 3:
arg0 = expr[0]
if arg0 is not None:
if potentially_variable(arg0):
raise ValueError(
"Constraint '%s' found a 3-tuple (lower,"
" expression, upper) but the lower "
"value was not data or an expression "
"restricted to storage of data."
% (self.name))
arg1 = expr[1]
if arg1 is not None:
arg1 = as_numeric(arg1)
arg2 = expr[2]
if arg2 is not None:
if potentially_variable(arg2):
raise ValueError(
"Constraint '%s' found a 3-tuple (lower,"
" expression, upper) but the upper "
"value was not data or an expression "
"restricted to storage of data."
% (self.name))
self.lb = arg0
self.body = arg1
self.ub = arg2
else:
raise ValueError(
"Constraint '%s' assigned a tuple "
"of length %d. Expecting a tuple of "
"length 2 or 3:\n"
"Equality: (body, rhs)\n"
"Inequality: (lb, body, ub)"
% (self.name, len(expr)))
relational_expr = False
else:
try:
relational_expr = expr.is_relational()
if not relational_expr:
raise ValueError(
"Constraint '%s' does not have a proper "
"value. Found '%s'\nExpecting a tuple or "
"equation. Examples:"
"\n sum_product(model.costs) == model.income"
"\n (0, model.price[item], 50)"
% (self.name, str(expr)))
except AttributeError:
msg = ("Constraint '%s' does not have a proper "
"value. Found '%s'\nExpecting a tuple or "
"equation. Examples:"
"\n sum_product(model.costs) == model.income"
"\n (0, model.price[item], 50)"
% (self.name, str(expr)))
if type(expr) is bool:
msg += ("\nNote: constant Boolean expressions "
"are not valid constraint expressions. "
"Some apparently non-constant compound "
"inequalities (e.g. 'expr >= 0 <= 1') "
"can return boolean values; the proper "
"form for compound inequalities is "
"always 'lb <= expr <= ub'.")
raise ValueError(msg)
#
# Special check for chainedInequality errors like "if var <
# 1:" within rules. Catching them here allows us to provide
# the user with better (and more immediate) debugging
# information. We don't want to check earlier because we
# want to provide a specific debugging message if the
# construction rule returned True/False; for example, if the
# user did ( var < 1 > 0 ) (which also results in a non-None
# chainedInequality value)
#
if EXPR._using_chained_inequality and \
(EXPR._chainedInequality.prev is not None):
raise TypeError(EXPR._chainedInequality.error_message())
#
# Process relational expressions
# (i.e. explicit '==', '<', and '<=')
#
if relational_expr:
if _expr_type is EXPR.EqualityExpression:
# assigning to the rhs property
# will set the equality flag to True
if not potentially_variable(expr.arg(1)):
self.rhs = expr.arg(1)
self.body = expr.arg(0)
elif not potentially_variable(expr.arg(0)):
self.rhs = expr.arg(0)
self.body = expr.arg(1)
else:
self.rhs = ZeroConstant
self.body = expr.arg(0)
self.body -= expr.arg(1)
elif _expr_type is EXPR.InequalityExpression:
if expr._strict:
raise ValueError(
"Constraint '%s' encountered a strict "
"inequality expression ('>' or '<'). All"
" constraints must be formulated using "
"using '<=', '>=', or '=='."
% (self.name))
if not potentially_variable(expr.arg(1)):
self.lb = None
self.body = expr.arg(0)
self.ub = expr.arg(1)
elif not potentially_variable(expr.arg(0)):
self.lb = expr.arg(0)
self.body = expr.arg(1)
self.ub = None
else:
self.lb = None
self.body = expr.arg(0)
self.body -= expr.arg(1)
self.ub = ZeroConstant
else: # RangedExpression
if any(expr._strict):
raise ValueError(
"Constraint '%s' encountered a strict "
"inequality expression ('>' or '<'). All"
" constraints must be formulated using "
"using '<=', '>=', or '=='."
% (self.name))
if potentially_variable(expr.arg(0)):
raise ValueError(
"Constraint '%s' found a double-sided "
"inequality expression (lower <= "
"expression <= upper) but the lower "
"bound was not data or an expression "
"restricted to storage of data."
% (self.name))
if potentially_variable(expr.arg(2)):
raise ValueError(
"Constraint '%s' found a double-sided "\
"inequality expression (lower <= "
"expression <= upper) but the upper "
"bound was not data or an expression "
"restricted to storage of data."
% (self.name))
self.lb = expr.arg(0)
self.body = expr.arg(1)
self.ub = expr.arg(2)
#
# Error check, to ensure that we don't have an equality
# constraint with 'infinite' RHS
#
assert not (self.equality and (self.lb is None))
assert (not self.equality) or (self.lb is self.ub)
def is_potentially_variable(self):
"""A boolean indicating whether this expression can
reference variables."""
return potentially_variable(self._expr)
def expr(self, expr):
if potentially_variable(expr):
raise ValueError("Expression is not restricted to data.")
self._expr = expr
