class Constraint(object):
""" Object that stores info for a single constraint. """
def __init__(self, lhs, comparator, rhs, scope, jacs=None):
self.lhs = ExprEvaluator(lhs, scope=scope)
self._pseudo = None
self.pcomp_name = None
unresolved_vars = self.lhs.get_unresolved()
if unresolved_vars:
msg = "Left hand side of constraint '{0}' has invalid variables {1}"
expression = ' '.join((lhs, comparator, rhs))
raise ExprEvaluator._invalid_expression_error(unresolved_vars,
expr=expression,
msg=msg)
self.rhs = ExprEvaluator(rhs, scope=scope)
unresolved_vars = self.rhs.get_unresolved()
if unresolved_vars:
msg = "Right hand side of constraint '{0}' has invalid variables {1}"
expression = ' '.join((lhs, comparator, rhs))
raise ExprEvaluator._invalid_expression_error(unresolved_vars,
expr=expression,
msg=msg)
self.comparator = comparator
self._size = None
# Linear flag: constraints are nonlinear by default
self.linear = False
# User-defined jacobian function
self.jacs = jacs
self._create_pseudo()
@property
def size(self):
"""Total scalar items in this constraint."""
if self._size is None:
self._size = len(self.evaluate(self.lhs.scope))
return self._size
def _create_pseudo(self):
"""Create our pseudo component."""
if self.comparator == '=':
subtype = 'equality'
else:
subtype = 'inequality'
# check for simple structure of equality constraint,
# either
# var1 = var2
# OR
# var1 - var2 = 0
# OR
# var1 = 0
lrefs = list(self.lhs.ordered_refs())
rrefs = list(self.rhs.ordered_refs())
try:
leftval = float(self.lhs.text)
except ValueError:
leftval = None
try:
rightval = float(self.rhs.text)
except ValueError:
rightval = None
pseudo_class = PseudoComponent
if self.comparator == '=':
# look for var1-var2=0
if len(lrefs) == 2 and len(rrefs) == 0:
if rightval == 0. and \
_remove_spaces(self.lhs.text) == \
lrefs[0]+'-'+lrefs[1]:
pseudo_class = SimpleEQConPComp
# look for 0=var1-var2
elif len(lrefs) == 0 and len(rrefs) == 2:
if leftval==0. and \
_remove_spaces(self.rhs.text) == \
rrefs[0]+'-'+rrefs[1]:
pseudo_class = SimpleEQConPComp
# look for var1=var2
elif len(lrefs) == 1 and len(rrefs) == 1:
if lrefs[0] == self.lhs.text and \
rrefs[0] == self.rhs.text:
pseudo_class = SimpleEQConPComp
# look for var1=0
elif len(lrefs) == 1 and len(rrefs) == 0 and rightval is not None:
pseudo_class = SimpleEQ0PComp
self._pseudo = pseudo_class(self.lhs.scope,
self._combined_expr(),
pseudo_type='constraint',
subtype=subtype,
exprobject=self)
self.pcomp_name = self._pseudo.name
def activate(self, driver):
"""Make this constraint active by creating the appropriate
connections in the dependency graph.
"""
self._pseudo.activate(self.lhs.scope, driver)
def deactivate(self):
"""Remove this constraint from the dependency graph and remove
its pseudocomp from the scoping object.
"""
if self._pseudo is not None:
scope = self.lhs.scope
try:
pcomp = getattr(scope, self._pseudo.name)
except AttributeError:
pass
else:
scope.remove(self._pseudo.name)
def _combined_expr(self):
"""Given a constraint object, take the lhs, operator, and
rhs and combine them into a single expression by moving rhs
terms over to the lhs. For example,
for the constraint 'C1.x < C2.y + 7', return the expression
'C1.x - C2.y - 7'. Depending on the direction of the operator,
the sign of the expression may be flipped. The final form of
the constraint, when evaluated, will be considered to be satisfied
if it evaluates to a value <= 0.
"""
scope = self.lhs.scope
if self.comparator.startswith('>'):
first = self.rhs.text
second = self.lhs.text
else:
first = self.lhs.text
second = self.rhs.text
first_zero = False
try:
f = float(first)
except Exception:
pass
else:
if f == 0:
first_zero = True
second_zero = False
try:
f = float(second)
except Exception:
pass
else:
if f == 0:
second_zero = True
if first_zero:
newexpr = "-(%s)" % second
elif second_zero:
newexpr = first
else:
newexpr = '%s-(%s)' % (first, second)
return ExprEvaluator(newexpr, scope)
def copy(self):
""" Returns a copy of our self. """
return Constraint(str(self.lhs), self.comparator, str(self.rhs),
scope=self.lhs.scope, jacs=self.jacs)
def evaluate(self, scope):
"""Returns the value of the constraint as a sequence."""
vname = self.pcomp_name + '.out0'
try:
system = getattr(scope,self.pcomp_name)._system
info = system.vec['u']._info[scope.name2collapsed[vname]]
# if a pseudocomp output is marked as hidden, that means that
# it's really a residual, but it's mapped in the vector to
# the corresponding state, so don't pull that value because
# we want the actual residual value
if info.hide: # it's a residual so pull from f vector
return -system.vec['f'][scope.name2collapsed[vname]]
else:
return info.view
except (KeyError, AttributeError):
pass
val = getattr(scope, self.pcomp_name).out0
if isinstance(val, ndarray):
return val.flatten()
else:
return [val]
def get_referenced_compnames(self):
"""Returns a set of names of each component referenced by this
constraint.
"""
if isinstance(self.rhs, float):
return self.lhs.get_referenced_compnames()
else:
return self.lhs.get_referenced_compnames().union(
self.rhs.get_referenced_compnames())
def get_referenced_varpaths(self, copy=True, refs=False):
"""Returns a set of names of each component referenced by this
constraint.
"""
if isinstance(self.rhs, float):
return self.lhs.get_referenced_varpaths(copy=copy, refs=refs)
else:
return self.lhs.get_referenced_varpaths(copy=copy, refs=refs).union(
self.rhs.get_referenced_varpaths(copy=copy, refs=refs))
def check_resolve(self):
"""Returns True if this constraint has no unresolved references."""
return self.lhs.check_resolve() and self.rhs.check_resolve()
def get_unresolved(self):
return list(set(self.lhs.get_unresolved()).union(self.rhs.get_unresolved()))
def name_changed(self, old, new):
"""Update expressions if necessary when an object is renamed."""
self.rhs.name_changed(old, new)
self.lhs.name_changed(old, new)
def __str__(self):
return ' '.join((str(self.lhs), self.comparator, str(self.rhs)))
def __eq__(self, other):
if not isinstance(other, Constraint):
return False
return (self.lhs, self.comparator, self.rhs) == \
(other.lhs, other.comparator, other.rhs)
class Constraint2Sided(Constraint):
""" Object that stores info for a double-sided constraint. """
def __init__(self, lhs, center, rhs, comparator, scope, jacs=None):
self.lhs = ExprEvaluator(lhs, scope=scope)
unresolved_vars = self.lhs.get_unresolved()
self._pseudo = None
self.pcomp_name = None
if unresolved_vars:
msg = "Left hand side of constraint '{0}' has invalid variables {1}"
expression = ' '.join((lhs, comparator, center, comparator,
rhs))
raise ExprEvaluator._invalid_expression_error(unresolved_vars,
expr=expression,
msg=msg)
self.center = ExprEvaluator(center, scope=scope)
unresolved_vars = self.center.get_unresolved()
if unresolved_vars:
msg = "Center of constraint '{0}' has invalid variables {1}"
expression = ' '.join((lhs, comparator, center, comparator,
rhs))
raise ExprEvaluator._invalid_expression_error(unresolved_vars,
expr=expression,
msg=msg)
self.rhs = ExprEvaluator(rhs, scope=scope)
unresolved_vars = self.rhs.get_unresolved()
if unresolved_vars:
msg = "Right hand side of constraint '{0}' has invalid variables {1}"
expression = ' '.join((lhs, comparator, center, comparator,
rhs))
raise ExprEvaluator._invalid_expression_error(unresolved_vars,
expr=expression,
msg=msg)
self.comparator = comparator
self._size = None
# Linear flag: constraints are nonlinear by default
self.linear = False
self.low = self.lhs.evaluate()
self.high = self.rhs.evaluate()
# User-defined jacobian function
self.jacs = jacs
self._create_pseudo()
def _create_pseudo(self):
"""Create our pseudo component."""
scope = self.lhs.scope
refs = list(self.center.ordered_refs())
pseudo_class = PseudoComponent
# look for a<var1<b
if len(refs) == 1 and self.center.text == refs[0]:
pseudo_class = SimpleEQ0PComp
self._pseudo = pseudo_class(scope,
self.center,
pseudo_type='constraint',
subtype='inequality',
exprobject=self)
self.pcomp_name = self._pseudo.name
def _combined_expr(self):
"""Only need the center expression
"""
return self.center
def copy(self):
""" Returns a copy of our self. """
return Constraint2Sided(str(self.lhs), str(self.center), str(self.rhs),
self.comparator, scope=self.lhs.scope,
jacs=self.jacs)
def get_referenced_compnames(self):
"""Returns a set of names of each component referenced by this
constraint.
"""
return self.center.get_referenced_compnames()
def get_referenced_varpaths(self, copy=True, refs=False):
"""Returns a set of names of each component referenced by this
constraint.
"""
return self.center.get_referenced_varpaths(copy=copy, refs=refs)
def name_changed(self, old, new):
"""Update expressions if necessary when an object is renamed."""
self.rhs.name_changed(old, new)
self.lhs.name_changed(old, new)
self.center.name_changed(old, new)
def __str__(self):
return ' '.join((str(self.lhs), str(self.center), str(self.rhs), self.comparator))
def __eq__(self, other):
if not isinstance(other, Constraint2Sided):
return False
return (self.lhs, self.center, self.comparator, self.rhs) == \
(other.lhs, self.center, other.comparator, other.rhs)
