Z3
Public Member Functions | Data Fields
Optimize Class Reference
+ Inheritance diagram for Optimize:

Public Member Functions

def __init__ (self, ctx=None)
 
def __deepcopy__ (self, memo={})
 
def __del__ (self)
 
def set (self, *args, **keys)
 
def help (self)
 
def param_descrs (self)
 
def assert_exprs (self, *args)
 
def add (self, *args)
 
def __iadd__ (self, fml)
 
def assert_and_track (self, a, p)
 
def add_soft (self, arg, weight="1", id=None)
 
def maximize (self, arg)
 
def minimize (self, arg)
 
def push (self)
 
def pop (self)
 
def check (self, *assumptions)
 
def reason_unknown (self)
 
def model (self)
 
def unsat_core (self)
 
def lower (self, obj)
 
def upper (self, obj)
 
def lower_values (self, obj)
 
def upper_values (self, obj)
 
def from_file (self, filename)
 
def from_string (self, s)
 
def assertions (self)
 
def objectives (self)
 
def __repr__ (self)
 
def sexpr (self)
 
def statistics (self)
 
- Public Member Functions inherited from Z3PPObject
def use_pp (self)
 

Data Fields

 ctx
 
 optimize
 

Detailed Description

Optimize API provides methods for solving using objective functions and weighted soft constraints

Definition at line 7357 of file z3py.py.

Constructor & Destructor Documentation

◆ __init__()

def __init__ (   self,
  ctx = None 
)

Definition at line 7360 of file z3py.py.

7360  def __init__(self, ctx=None):
7361  self.ctx = _get_ctx(ctx)
7362  self.optimize = Z3_mk_optimize(self.ctx.ref())
7363  Z3_optimize_inc_ref(self.ctx.ref(), self.optimize)
7364 

◆ __del__()

def __del__ (   self)

Definition at line 7368 of file z3py.py.

7368  def __del__(self):
7369  if self.optimize is not None and self.ctx.ref() is not None:
7370  Z3_optimize_dec_ref(self.ctx.ref(), self.optimize)
7371 

Member Function Documentation

◆ __deepcopy__()

def __deepcopy__ (   self,
  memo = {} 
)

Definition at line 7365 of file z3py.py.

7365  def __deepcopy__(self, memo={}):
7366  return Optimize(self.optimize, self.ctx)
7367 

◆ __iadd__()

def __iadd__ (   self,
  fml 
)

Definition at line 7402 of file z3py.py.

7402  def __iadd__(self, fml):
7403  self.add(fml)
7404  return self
7405 

◆ __repr__()

def __repr__ (   self)
Return a formatted string with all added rules and constraints.

Definition at line 7529 of file z3py.py.

7529  def __repr__(self):
7530  """Return a formatted string with all added rules and constraints."""
7531  return self.sexpr()
7532 

◆ add()

def add (   self,
args 
)
Assert constraints as background axioms for the optimize solver. Alias for assert_expr.

Definition at line 7398 of file z3py.py.

7398  def add(self, *args):
7399  """Assert constraints as background axioms for the optimize solver. Alias for assert_expr."""
7400  self.assert_exprs(*args)
7401 

Referenced by Optimize.__iadd__().

◆ add_soft()

def add_soft (   self,
  arg,
  weight = "1",
  id = None 
)
Add soft constraint with optional weight and optional identifier.
   If no weight is supplied, then the penalty for violating the soft constraint
   is 1.
   Soft constraints are grouped by identifiers. Soft constraints that are
   added without identifiers are grouped by default.

Definition at line 7435 of file z3py.py.

7435  def add_soft(self, arg, weight = "1", id = None):
7436  """Add soft constraint with optional weight and optional identifier.
7437  If no weight is supplied, then the penalty for violating the soft constraint
7438  is 1.
7439  Soft constraints are grouped by identifiers. Soft constraints that are
7440  added without identifiers are grouped by default.
7441  """
7442  if _is_int(weight):
7443  weight = "%d" % weight
7444  elif isinstance(weight, float):
7445  weight = "%f" % weight
7446  if not isinstance(weight, str):
7447  raise Z3Exception("weight should be a string or an integer")
7448  if id is None:
7449  id = ""
7450  id = to_symbol(id, self.ctx)
7451  v = Z3_optimize_assert_soft(self.ctx.ref(), self.optimize, arg.as_ast(), weight, id)
7452  return OptimizeObjective(self, v, False)
7453 

◆ assert_and_track()

def assert_and_track (   self,
  a,
  p 
)
Assert constraint `a` and track it in the unsat core using the Boolean constant `p`.

If `p` is a string, it will be automatically converted into a Boolean constant.

>>> x = Int('x')
>>> p3 = Bool('p3')
>>> s = Optimize()
>>> s.assert_and_track(x > 0,  'p1')
>>> s.assert_and_track(x != 1, 'p2')
>>> s.assert_and_track(x < 0,  p3)
>>> print(s.check())
unsat
>>> c = s.unsat_core()
>>> len(c)
2
>>> Bool('p1') in c
True
>>> Bool('p2') in c
False
>>> p3 in c
True

Definition at line 7406 of file z3py.py.

7406  def assert_and_track(self, a, p):
7407  """Assert constraint `a` and track it in the unsat core using the Boolean constant `p`.
7408 
7409  If `p` is a string, it will be automatically converted into a Boolean constant.
7410 
7411  >>> x = Int('x')
7412  >>> p3 = Bool('p3')
7413  >>> s = Optimize()
7414  >>> s.assert_and_track(x > 0, 'p1')
7415  >>> s.assert_and_track(x != 1, 'p2')
7416  >>> s.assert_and_track(x < 0, p3)
7417  >>> print(s.check())
7418  unsat
7419  >>> c = s.unsat_core()
7420  >>> len(c)
7421  2
7422  >>> Bool('p1') in c
7423  True
7424  >>> Bool('p2') in c
7425  False
7426  >>> p3 in c
7427  True
7428  """
7429  if isinstance(p, str):
7430  p = Bool(p, self.ctx)
7431  _z3_assert(isinstance(a, BoolRef), "Boolean expression expected")
7432  _z3_assert(isinstance(p, BoolRef) and is_const(p), "Boolean expression expected")
7433  Z3_optimize_assert_and_track(self.ctx.ref(), self.optimize, a.as_ast(), p.as_ast())
7434 

◆ assert_exprs()

def assert_exprs (   self,
args 
)
Assert constraints as background axioms for the optimize solver.

Definition at line 7386 of file z3py.py.

7386  def assert_exprs(self, *args):
7387  """Assert constraints as background axioms for the optimize solver."""
7388  args = _get_args(args)
7389  s = BoolSort(self.ctx)
7390  for arg in args:
7391  if isinstance(arg, Goal) or isinstance(arg, AstVector):
7392  for f in arg:
7393  Z3_optimize_assert(self.ctx.ref(), self.optimize, f.as_ast())
7394  else:
7395  arg = s.cast(arg)
7396  Z3_optimize_assert(self.ctx.ref(), self.optimize, arg.as_ast())
7397 

Referenced by Optimize.add().

◆ assertions()

def assertions (   self)
Return an AST vector containing all added constraints.

Definition at line 7521 of file z3py.py.

7521  def assertions(self):
7522  """Return an AST vector containing all added constraints."""
7523  return AstVector(Z3_optimize_get_assertions(self.ctx.ref(), self.optimize), self.ctx)
7524 

◆ check()

def check (   self,
assumptions 
)
Check satisfiability while optimizing objective functions.

Definition at line 7470 of file z3py.py.

7470  def check(self, *assumptions):
7471  """Check satisfiability while optimizing objective functions."""
7472  assumptions = _get_args(assumptions)
7473  num = len(assumptions)
7474  _assumptions = (Ast * num)()
7475  for i in range(num):
7476  _assumptions[i] = assumptions[i].as_ast()
7477  return CheckSatResult(Z3_optimize_check(self.ctx.ref(), self.optimize, num, _assumptions))
7478 

◆ from_file()

def from_file (   self,
  filename 
)
Parse assertions and objectives from a file

Definition at line 7513 of file z3py.py.

7513  def from_file(self, filename):
7514  """Parse assertions and objectives from a file"""
7515  Z3_optimize_from_file(self.ctx.ref(), self.optimize, filename)
7516 

◆ from_string()

def from_string (   self,
  s 
)
Parse assertions and objectives from a string

Definition at line 7517 of file z3py.py.

7517  def from_string(self, s):
7518  """Parse assertions and objectives from a string"""
7519  Z3_optimize_from_string(self.ctx.ref(), self.optimize, s)
7520 

◆ help()

def help (   self)
Display a string describing all available options.

Definition at line 7378 of file z3py.py.

7378  def help(self):
7379  """Display a string describing all available options."""
7380  print(Z3_optimize_get_help(self.ctx.ref(), self.optimize))
7381 

◆ lower()

def lower (   self,
  obj 
)

Definition at line 7493 of file z3py.py.

7493  def lower(self, obj):
7494  if not isinstance(obj, OptimizeObjective):
7495  raise Z3Exception("Expecting objective handle returned by maximize/minimize")
7496  return obj.lower()
7497 

◆ lower_values()

def lower_values (   self,
  obj 
)

Definition at line 7503 of file z3py.py.

7503  def lower_values(self, obj):
7504  if not isinstance(obj, OptimizeObjective):
7505  raise Z3Exception("Expecting objective handle returned by maximize/minimize")
7506  return obj.lower_values()
7507 

◆ maximize()

def maximize (   self,
  arg 
)
Add objective function to maximize.

Definition at line 7454 of file z3py.py.

7454  def maximize(self, arg):
7455  """Add objective function to maximize."""
7456  return OptimizeObjective(self, Z3_optimize_maximize(self.ctx.ref(), self.optimize, arg.as_ast()), True)
7457 

◆ minimize()

def minimize (   self,
  arg 
)
Add objective function to minimize.

Definition at line 7458 of file z3py.py.

7458  def minimize(self, arg):
7459  """Add objective function to minimize."""
7460  return OptimizeObjective(self, Z3_optimize_minimize(self.ctx.ref(), self.optimize, arg.as_ast()), False)
7461 

◆ model()

def model (   self)
Return a model for the last check().

Definition at line 7483 of file z3py.py.

7483  def model(self):
7484  """Return a model for the last check()."""
7485  try:
7486  return ModelRef(Z3_optimize_get_model(self.ctx.ref(), self.optimize), self.ctx)
7487  except Z3Exception:
7488  raise Z3Exception("model is not available")
7489 

Referenced by FuncInterp.translate().

◆ objectives()

def objectives (   self)
returns set of objective functions

Definition at line 7525 of file z3py.py.

7525  def objectives(self):
7526  """returns set of objective functions"""
7527  return AstVector(Z3_optimize_get_objectives(self.ctx.ref(), self.optimize), self.ctx)
7528 

◆ param_descrs()

def param_descrs (   self)
Return the parameter description set.

Definition at line 7382 of file z3py.py.

7382  def param_descrs(self):
7383  """Return the parameter description set."""
7384  return ParamDescrsRef(Z3_optimize_get_param_descrs(self.ctx.ref(), self.optimize), self.ctx)
7385 

◆ pop()

def pop (   self)
restore to previously created backtracking point

Definition at line 7466 of file z3py.py.

7466  def pop(self):
7467  """restore to previously created backtracking point"""
7468  Z3_optimize_pop(self.ctx.ref(), self.optimize)
7469 

◆ push()

def push (   self)
create a backtracking point for added rules, facts and assertions

Definition at line 7462 of file z3py.py.

7462  def push(self):
7463  """create a backtracking point for added rules, facts and assertions"""
7464  Z3_optimize_push(self.ctx.ref(), self.optimize)
7465 

◆ reason_unknown()

def reason_unknown (   self)
Return a string that describes why the last `check()` returned `unknown`.

Definition at line 7479 of file z3py.py.

7479  def reason_unknown(self):
7480  """Return a string that describes why the last `check()` returned `unknown`."""
7481  return Z3_optimize_get_reason_unknown(self.ctx.ref(), self.optimize)
7482 

◆ set()

def set (   self,
args,
**  keys 
)
Set a configuration option. The method `help()` return a string containing all available options.

Definition at line 7372 of file z3py.py.

7372  def set(self, *args, **keys):
7373  """Set a configuration option. The method `help()` return a string containing all available options.
7374  """
7375  p = args2params(args, keys, self.ctx)
7376  Z3_optimize_set_params(self.ctx.ref(), self.optimize, p.params)
7377 

◆ sexpr()

def sexpr (   self)
Return a formatted string (in Lisp-like format) with all added constraints. We say the string is in s-expression format.

Definition at line 7533 of file z3py.py.

7533  def sexpr(self):
7534  """Return a formatted string (in Lisp-like format) with all added constraints. We say the string is in s-expression format.
7535  """
7536  return Z3_optimize_to_string(self.ctx.ref(), self.optimize)
7537 

Referenced by Optimize.__repr__().

◆ statistics()

def statistics (   self)
Return statistics for the last check`.

Definition at line 7538 of file z3py.py.

7538  def statistics(self):
7539  """Return statistics for the last check`.
7540  """
7541  return Statistics(Z3_optimize_get_statistics(self.ctx.ref(), self.optimize), self.ctx)
7542 
7543 
7544 
7545 

◆ unsat_core()

def unsat_core (   self)

Definition at line 7490 of file z3py.py.

7490  def unsat_core(self):
7491  return AstVector(Z3_optimize_get_unsat_core(self.ctx.ref(), self.optimize), self.ctx)
7492 

◆ upper()

def upper (   self,
  obj 
)

Definition at line 7498 of file z3py.py.

7498  def upper(self, obj):
7499  if not isinstance(obj, OptimizeObjective):
7500  raise Z3Exception("Expecting objective handle returned by maximize/minimize")
7501  return obj.upper()
7502 

◆ upper_values()

def upper_values (   self,
  obj 
)

Definition at line 7508 of file z3py.py.

7508  def upper_values(self, obj):
7509  if not isinstance(obj, OptimizeObjective):
7510  raise Z3Exception("Expecting objective handle returned by maximize/minimize")
7511  return obj.upper_values()
7512 

Field Documentation

◆ ctx

ctx

◆ optimize

optimize
Z3_optimize_pop
void Z3_API Z3_optimize_pop(Z3_context c, Z3_optimize d)
Backtrack one level.
Z3_optimize_assert_and_track
void Z3_API Z3_optimize_assert_and_track(Z3_context c, Z3_optimize o, Z3_ast a, Z3_ast t)
Assert tracked hard constraint to the optimization context.
Z3_optimize_dec_ref
void Z3_API Z3_optimize_dec_ref(Z3_context c, Z3_optimize d)
Decrement the reference counter of the given optimize context.
Z3_optimize_get_reason_unknown
Z3_string Z3_API Z3_optimize_get_reason_unknown(Z3_context c, Z3_optimize d)
Retrieve a string that describes the last status returned by Z3_optimize_check.
z3::range
expr range(expr const &lo, expr const &hi)
Definition: z3++.h:3431
Z3_optimize_from_string
void Z3_API Z3_optimize_from_string(Z3_context c, Z3_optimize o, Z3_string s)
Parse an SMT-LIB2 string with assertions, soft constraints and optimization objectives....
Z3_optimize_get_objectives
Z3_ast_vector Z3_API Z3_optimize_get_objectives(Z3_context c, Z3_optimize o)
Return objectives on the optimization context. If the objective function is a max-sat objective it is...
Z3_optimize_get_statistics
Z3_stats Z3_API Z3_optimize_get_statistics(Z3_context c, Z3_optimize d)
Retrieve statistics information from the last call to Z3_optimize_check.
Z3_optimize_get_assertions
Z3_ast_vector Z3_API Z3_optimize_get_assertions(Z3_context c, Z3_optimize o)
Return the set of asserted formulas on the optimization context.
Z3_optimize_get_param_descrs
Z3_param_descrs Z3_API Z3_optimize_get_param_descrs(Z3_context c, Z3_optimize o)
Return the parameter description set for the given optimize object.
z3py.to_symbol
def to_symbol(s, ctx=None)
Definition: z3py.py:109
Z3_optimize_assert_soft
unsigned Z3_API Z3_optimize_assert_soft(Z3_context c, Z3_optimize o, Z3_ast a, Z3_string weight, Z3_symbol id)
Assert soft constraint to the optimization context.
Z3_optimize_maximize
unsigned Z3_API Z3_optimize_maximize(Z3_context c, Z3_optimize o, Z3_ast t)
Add a maximization constraint.
Z3_optimize_to_string
Z3_string Z3_API Z3_optimize_to_string(Z3_context c, Z3_optimize o)
Print the current context as a string.
z3py.is_const
def is_const(a)
Definition: z3py.py:1162
Z3_optimize_check
Z3_lbool Z3_API Z3_optimize_check(Z3_context c, Z3_optimize o, unsigned num_assumptions, Z3_ast const assumptions[])
Check consistency and produce optimal values.
Z3_optimize_assert
void Z3_API Z3_optimize_assert(Z3_context c, Z3_optimize o, Z3_ast a)
Assert hard constraint to the optimization context.
Z3_optimize_from_file
void Z3_API Z3_optimize_from_file(Z3_context c, Z3_optimize o, Z3_string s)
Parse an SMT-LIB2 file with assertions, soft constraints and optimization objectives....
Z3_optimize_set_params
void Z3_API Z3_optimize_set_params(Z3_context c, Z3_optimize o, Z3_params p)
Set parameters on optimization context.
Z3_mk_optimize
Z3_optimize Z3_API Z3_mk_optimize(Z3_context c)
Create a new optimize context.
z3py.Bool
def Bool(name, ctx=None)
Definition: z3py.py:1568
Z3_optimize_push
void Z3_API Z3_optimize_push(Z3_context c, Z3_optimize d)
Create a backtracking point.
Z3_optimize_get_unsat_core
Z3_ast_vector Z3_API Z3_optimize_get_unsat_core(Z3_context c, Z3_optimize o)
Retrieve the unsat core for the last Z3_optimize_check The unsat core is a subset of the assumptions ...
Z3_optimize_get_model
Z3_model Z3_API Z3_optimize_get_model(Z3_context c, Z3_optimize o)
Retrieve the model for the last Z3_optimize_check.
z3py.args2params
def args2params(arguments, keywords, ctx=None)
Definition: z3py.py:5070
z3py.BoolSort
def BoolSort(ctx=None)
Definition: z3py.py:1533
Z3_optimize_get_help
Z3_string Z3_API Z3_optimize_get_help(Z3_context c, Z3_optimize t)
Return a string containing a description of parameters accepted by optimize.
Z3_optimize_minimize
unsigned Z3_API Z3_optimize_minimize(Z3_context c, Z3_optimize o, Z3_ast t)
Add a minimization constraint.
Z3_optimize_inc_ref
void Z3_API Z3_optimize_inc_ref(Z3_context c, Z3_optimize d)
Increment the reference counter of the given optimize context.