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Fixedpoint Class Reference

Fixedpoint. More...

Inheritance diagram for Fixedpoint:

Public Member Functions

 __init__ (self, fixedpoint=None, ctx=None)
 __deepcopy__ (self, memo={})
 __del__ (self)
 set (self, *args, **keys)
 help (self)
 param_descrs (self)
 assert_exprs (self, *args)
 add (self, *args)
 __iadd__ (self, fml)
 append (self, *args)
 insert (self, *args)
 add_rule (self, head, body=None, name=None)
 rule (self, head, body=None, name=None)
 fact (self, head, name=None)
 query (self, *query)
 query_from_lvl (self, lvl, *query)
 update_rule (self, head, body, name)
 get_answer (self)
 get_ground_sat_answer (self)
 get_rules_along_trace (self)
 get_rule_names_along_trace (self)
 get_num_levels (self, predicate)
 get_cover_delta (self, level, predicate)
 add_cover (self, level, predicate, property)
 register_relation (self, *relations)
 set_predicate_representation (self, f, *representations)
 parse_string (self, s)
 parse_file (self, f)
 get_rules (self)
 get_assertions (self)
 __repr__ (self)
 sexpr (self)
 to_string (self, queries)
 statistics (self)
 reason_unknown (self)
 declare_var (self, *vars)
 abstract (self, fml, is_forall=True)
Public Member Functions inherited from Z3PPObject
 use_pp (self)

Data Fields

 ctx = _get_ctx(ctx)
 fixedpoint = None
list vars = []

Additional Inherited Members

Protected Member Functions inherited from Z3PPObject
 _repr_html_ (self)

Detailed Description

Fixedpoint.

Fixedpoint API provides methods for solving with recursive predicates

Definition at line 7766 of file z3py.py.

Constructor & Destructor Documentation

◆ __init__()

__init__ ( self,
fixedpoint = None,
ctx = None )

Definition at line 7769 of file z3py.py.

7769 def __init__(self, fixedpoint=None, ctx=None):
7770 assert fixedpoint is None or ctx is not None
7771 self.ctx = _get_ctx(ctx)
7772 self.fixedpoint = None
7773 if fixedpoint is None:
7774 self.fixedpoint = Z3_mk_fixedpoint(self.ctx.ref())
7775 else:
7776 self.fixedpoint = fixedpoint
7777 Z3_fixedpoint_inc_ref(self.ctx.ref(), self.fixedpoint)
7778 self.vars = []
7779
void Z3_API Z3_fixedpoint_inc_ref(Z3_context c, Z3_fixedpoint d)
Increment the reference counter of the given fixedpoint context.
Z3_fixedpoint Z3_API Z3_mk_fixedpoint(Z3_context c)
Create a new fixedpoint context.

◆ __del__()

__del__ ( self)

Definition at line 7783 of file z3py.py.

7783 def __del__(self):
7784 if self.fixedpoint is not None and self.ctx.ref() is not None and Z3_fixedpoint_dec_ref is not None:
7785 Z3_fixedpoint_dec_ref(self.ctx.ref(), self.fixedpoint)
7786
void Z3_API Z3_fixedpoint_dec_ref(Z3_context c, Z3_fixedpoint d)
Decrement the reference counter of the given fixedpoint context.

Member Function Documentation

◆ __deepcopy__()

__deepcopy__ ( self,
memo = {} )

Definition at line 7780 of file z3py.py.

7780 def __deepcopy__(self, memo={}):
7781 return FixedPoint(self.fixedpoint, self.ctx)
7782

◆ __iadd__()

__iadd__ ( self,
fml )

Definition at line 7819 of file z3py.py.

7819 def __iadd__(self, fml):
7820 self.add(fml)
7821 return self
7822

◆ __repr__()

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

Definition at line 7980 of file z3py.py.

7980 def __repr__(self):
7981 """Return a formatted string with all added rules and constraints."""
7982 return self.sexpr()
7983

◆ abstract()

abstract ( self,
fml,
is_forall = True )

Definition at line 8017 of file z3py.py.

8017 def abstract(self, fml, is_forall=True):
8018 if self.vars == []:
8019 return fml
8020 if is_forall:
8021 return ForAll(self.vars, fml)
8022 else:
8023 return Exists(self.vars, fml)
8024
8025

◆ add()

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

Definition at line 7815 of file z3py.py.

7815 def add(self, *args):
7816 """Assert constraints as background axioms for the fixedpoint solver. Alias for assert_expr."""
7817 self.assert_exprs(*args)
7818

◆ add_cover()

add_cover ( self,
level,
predicate,
property )
Add property to predicate for the level'th unfolding.
-1 is treated as infinity (infinity)

Definition at line 7942 of file z3py.py.

7942 def add_cover(self, level, predicate, property):
7943 """Add property to predicate for the level'th unfolding.
7944 -1 is treated as infinity (infinity)
7945 """
7946 Z3_fixedpoint_add_cover(self.ctx.ref(), self.fixedpoint, level, predicate.ast, property.ast)
7947
void Z3_API Z3_fixedpoint_add_cover(Z3_context c, Z3_fixedpoint d, int level, Z3_func_decl pred, Z3_ast property)
Add property about the predicate pred. Add a property of predicate pred at level. It gets pushed forw...

◆ add_rule()

add_rule ( self,
head,
body = None,
name = None )
Assert rules defining recursive predicates to the fixedpoint solver.
>>> a = Bool('a')
>>> b = Bool('b')
>>> s = Fixedpoint()
>>> s.register_relation(a.decl())
>>> s.register_relation(b.decl())
>>> s.fact(a)
>>> s.rule(b, a)
>>> s.query(b)
sat

Definition at line 7831 of file z3py.py.

7831 def add_rule(self, head, body=None, name=None):
7832 """Assert rules defining recursive predicates to the fixedpoint solver.
7833 >>> a = Bool('a')
7834 >>> b = Bool('b')
7835 >>> s = Fixedpoint()
7836 >>> s.register_relation(a.decl())
7837 >>> s.register_relation(b.decl())
7838 >>> s.fact(a)
7839 >>> s.rule(b, a)
7840 >>> s.query(b)
7841 sat
7842 """
7843 if name is None:
7844 name = ""
7845 name = to_symbol(name, self.ctx)
7846 if body is None:
7847 head = self.abstract(head)
7848 Z3_fixedpoint_add_rule(self.ctx.ref(), self.fixedpoint, head.as_ast(), name)
7849 else:
7850 body = _get_args(body)
7851 f = self.abstract(Implies(And(body, self.ctx), head))
7852 Z3_fixedpoint_add_rule(self.ctx.ref(), self.fixedpoint, f.as_ast(), name)
7853
void Z3_API Z3_fixedpoint_add_rule(Z3_context c, Z3_fixedpoint d, Z3_ast rule, Z3_symbol name)
Add a universal Horn clause as a named rule. The horn_rule should be of the form:

◆ append()

append ( self,
* args )
Assert constraints as background axioms for the fixedpoint solver. Alias for assert_expr.

Definition at line 7823 of file z3py.py.

7823 def append(self, *args):
7824 """Assert constraints as background axioms for the fixedpoint solver. Alias for assert_expr."""
7825 self.assert_exprs(*args)
7826

◆ assert_exprs()

assert_exprs ( self,
* args )
Assert constraints as background axioms for the fixedpoint solver.

Definition at line 7801 of file z3py.py.

7801 def assert_exprs(self, *args):
7802 """Assert constraints as background axioms for the fixedpoint solver."""
7803 args = _get_args(args)
7804 s = BoolSort(self.ctx)
7805 for arg in args:
7806 if isinstance(arg, Goal) or isinstance(arg, AstVector):
7807 for f in arg:
7808 f = self.abstract(f)
7809 Z3_fixedpoint_assert(self.ctx.ref(), self.fixedpoint, f.as_ast())
7810 else:
7811 arg = s.cast(arg)
7812 arg = self.abstract(arg)
7813 Z3_fixedpoint_assert(self.ctx.ref(), self.fixedpoint, arg.as_ast())
7814
void Z3_API Z3_fixedpoint_assert(Z3_context c, Z3_fixedpoint d, Z3_ast axiom)
Assert a constraint to the fixedpoint context.

◆ declare_var()

declare_var ( self,
* vars )
Add variable or several variables.
The added variable or variables will be bound in the rules
and queries

Definition at line 8008 of file z3py.py.

8008 def declare_var(self, *vars):
8009 """Add variable or several variables.
8010 The added variable or variables will be bound in the rules
8011 and queries
8012 """
8013 vars = _get_args(vars)
8014 for v in vars:
8015 self.vars += [v]
8016

◆ fact()

fact ( self,
head,
name = None )
Assert facts defining recursive predicates to the fixedpoint solver. Alias for add_rule.

Definition at line 7858 of file z3py.py.

7858 def fact(self, head, name=None):
7859 """Assert facts defining recursive predicates to the fixedpoint solver. Alias for add_rule."""
7860 self.add_rule(head, None, name)
7861

◆ get_answer()

get_answer ( self)
Retrieve answer from last query call.

Definition at line 7909 of file z3py.py.

7909 def get_answer(self):
7910 """Retrieve answer from last query call."""
7911 r = Z3_fixedpoint_get_answer(self.ctx.ref(), self.fixedpoint)
7912 return _to_expr_ref(r, self.ctx)
7913
Z3_ast Z3_API Z3_fixedpoint_get_answer(Z3_context c, Z3_fixedpoint d)
Retrieve a formula that encodes satisfying answers to the query.

◆ get_assertions()

get_assertions ( self)
retrieve assertions that have been added to fixedpoint context

Definition at line 7976 of file z3py.py.

7976 def get_assertions(self):
7977 """retrieve assertions that have been added to fixedpoint context"""
7978 return AstVector(Z3_fixedpoint_get_assertions(self.ctx.ref(), self.fixedpoint), self.ctx)
7979
Z3_ast_vector Z3_API Z3_fixedpoint_get_assertions(Z3_context c, Z3_fixedpoint f)
Retrieve set of background assertions from fixedpoint context.

◆ get_cover_delta()

get_cover_delta ( self,
level,
predicate )
Retrieve properties known about predicate for the level'th unfolding.
-1 is treated as the limit (infinity)

Definition at line 7935 of file z3py.py.

7935 def get_cover_delta(self, level, predicate):
7936 """Retrieve properties known about predicate for the level'th unfolding.
7937 -1 is treated as the limit (infinity)
7938 """
7939 r = Z3_fixedpoint_get_cover_delta(self.ctx.ref(), self.fixedpoint, level, predicate.ast)
7940 return _to_expr_ref(r, self.ctx)
7941
Z3_ast Z3_API Z3_fixedpoint_get_cover_delta(Z3_context c, Z3_fixedpoint d, int level, Z3_func_decl pred)

◆ get_ground_sat_answer()

get_ground_sat_answer ( self)
Retrieve a ground cex from last query call.

Definition at line 7914 of file z3py.py.

7914 def get_ground_sat_answer(self):
7915 """Retrieve a ground cex from last query call."""
7916 r = Z3_fixedpoint_get_ground_sat_answer(self.ctx.ref(), self.fixedpoint)
7917 return _to_expr_ref(r, self.ctx)
7918

◆ get_num_levels()

get_num_levels ( self,
predicate )
Retrieve number of levels used for predicate in PDR engine

Definition at line 7931 of file z3py.py.

7931 def get_num_levels(self, predicate):
7932 """Retrieve number of levels used for predicate in PDR engine"""
7933 return Z3_fixedpoint_get_num_levels(self.ctx.ref(), self.fixedpoint, predicate.ast)
7934
unsigned Z3_API Z3_fixedpoint_get_num_levels(Z3_context c, Z3_fixedpoint d, Z3_func_decl pred)
Query the PDR engine for the maximal levels properties are known about predicate.

◆ get_rule_names_along_trace()

get_rule_names_along_trace ( self)
retrieve rule names along the counterexample trace

Definition at line 7923 of file z3py.py.

7923 def get_rule_names_along_trace(self):
7924 """retrieve rule names along the counterexample trace"""
7925 # this is a hack as I don't know how to return a list of symbols from C++;
7926 # obtain names as a single string separated by semicolons
7927 names = _symbol2py(self.ctx, Z3_fixedpoint_get_rule_names_along_trace(self.ctx.ref(), self.fixedpoint))
7928 # split into individual names
7929 return names.split(";")
7930

◆ get_rules()

get_rules ( self)
retrieve rules that have been added to fixedpoint context

Definition at line 7972 of file z3py.py.

7972 def get_rules(self):
7973 """retrieve rules that have been added to fixedpoint context"""
7974 return AstVector(Z3_fixedpoint_get_rules(self.ctx.ref(), self.fixedpoint), self.ctx)
7975
Z3_ast_vector Z3_API Z3_fixedpoint_get_rules(Z3_context c, Z3_fixedpoint f)
Retrieve set of rules from fixedpoint context.

◆ get_rules_along_trace()

get_rules_along_trace ( self)
retrieve rules along the counterexample trace

Definition at line 7919 of file z3py.py.

7919 def get_rules_along_trace(self):
7920 """retrieve rules along the counterexample trace"""
7921 return AstVector(Z3_fixedpoint_get_rules_along_trace(self.ctx.ref(), self.fixedpoint), self.ctx)
7922

◆ help()

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

Definition at line 7793 of file z3py.py.

7793 def help(self):
7794 """Display a string describing all available options."""
7795 print(Z3_fixedpoint_get_help(self.ctx.ref(), self.fixedpoint))
7796
Z3_string Z3_API Z3_fixedpoint_get_help(Z3_context c, Z3_fixedpoint f)
Return a string describing all fixedpoint available parameters.

◆ insert()

insert ( self,
* args )
Assert constraints as background axioms for the fixedpoint solver. Alias for assert_expr.

Definition at line 7827 of file z3py.py.

7827 def insert(self, *args):
7828 """Assert constraints as background axioms for the fixedpoint solver. Alias for assert_expr."""
7829 self.assert_exprs(*args)
7830

◆ param_descrs()

param_descrs ( self)
Return the parameter description set.

Definition at line 7797 of file z3py.py.

7797 def param_descrs(self):
7798 """Return the parameter description set."""
7799 return ParamDescrsRef(Z3_fixedpoint_get_param_descrs(self.ctx.ref(), self.fixedpoint), self.ctx)
7800
Z3_param_descrs Z3_API Z3_fixedpoint_get_param_descrs(Z3_context c, Z3_fixedpoint f)
Return the parameter description set for the given fixedpoint object.

◆ parse_file()

parse_file ( self,
f )
Parse rules and queries from a file

Definition at line 7968 of file z3py.py.

7968 def parse_file(self, f):
7969 """Parse rules and queries from a file"""
7970 return AstVector(Z3_fixedpoint_from_file(self.ctx.ref(), self.fixedpoint, f), self.ctx)
7971
Z3_ast_vector Z3_API Z3_fixedpoint_from_file(Z3_context c, Z3_fixedpoint f, Z3_string s)
Parse an SMT-LIB2 file with fixedpoint rules. Add the rules to the current fixedpoint context....

◆ parse_string()

parse_string ( self,
s )
Parse rules and queries from a string

Definition at line 7964 of file z3py.py.

7964 def parse_string(self, s):
7965 """Parse rules and queries from a string"""
7966 return AstVector(Z3_fixedpoint_from_string(self.ctx.ref(), self.fixedpoint, s), self.ctx)
7967
Z3_ast_vector Z3_API Z3_fixedpoint_from_string(Z3_context c, Z3_fixedpoint f, Z3_string s)
Parse an SMT-LIB2 string with fixedpoint rules. Add the rules to the current fixedpoint context....

◆ query()

query ( self,
* query )
Query the fixedpoint engine whether formula is derivable.
   You can also pass an tuple or list of recursive predicates.

Definition at line 7862 of file z3py.py.

7862 def query(self, *query):
7863 """Query the fixedpoint engine whether formula is derivable.
7864 You can also pass an tuple or list of recursive predicates.
7865 """
7866 query = _get_args(query)
7867 sz = len(query)
7868 if sz >= 1 and isinstance(query[0], FuncDeclRef):
7869 _decls = (FuncDecl * sz)()
7870 i = 0
7871 for q in query:
7872 _decls[i] = q.ast
7873 i = i + 1
7874 r = Z3_fixedpoint_query_relations(self.ctx.ref(), self.fixedpoint, sz, _decls)
7875 else:
7876 if sz == 1:
7877 query = query[0]
7878 else:
7879 query = And(query, self.ctx)
7880 query = self.abstract(query, False)
7881 r = Z3_fixedpoint_query(self.ctx.ref(), self.fixedpoint, query.as_ast())
7882 return CheckSatResult(r)
7883
Z3_lbool Z3_API Z3_fixedpoint_query(Z3_context c, Z3_fixedpoint d, Z3_ast query)
Pose a query against the asserted rules.
Z3_lbool Z3_API Z3_fixedpoint_query_relations(Z3_context c, Z3_fixedpoint d, unsigned num_relations, Z3_func_decl const relations[])
Pose multiple queries against the asserted rules.

◆ query_from_lvl()

query_from_lvl ( self,
lvl,
* query )
Query the fixedpoint engine whether formula is derivable starting at the given query level.

Definition at line 7884 of file z3py.py.

7884 def query_from_lvl(self, lvl, *query):
7885 """Query the fixedpoint engine whether formula is derivable starting at the given query level.
7886 """
7887 query = _get_args(query)
7888 sz = len(query)
7889 if sz >= 1 and isinstance(query[0], FuncDecl):
7890 _z3_assert(False, "unsupported")
7891 else:
7892 if sz == 1:
7893 query = query[0]
7894 else:
7895 query = And(query)
7896 query = self.abstract(query, False)
7897 r = Z3_fixedpoint_query_from_lvl(self.ctx.ref(), self.fixedpoint, query.as_ast(), lvl)
7898 return CheckSatResult(r)
7899

◆ reason_unknown()

reason_unknown ( self)
Return a string describing why the last `query()` returned `unknown`.

Definition at line 8003 of file z3py.py.

8003 def reason_unknown(self):
8004 """Return a string describing why the last `query()` returned `unknown`.
8005 """
8006 return Z3_fixedpoint_get_reason_unknown(self.ctx.ref(), self.fixedpoint)
8007
Z3_string Z3_API Z3_fixedpoint_get_reason_unknown(Z3_context c, Z3_fixedpoint d)
Retrieve a string that describes the last status returned by Z3_fixedpoint_query.

◆ register_relation()

register_relation ( self,
* relations )
Register relation as recursive

Definition at line 7948 of file z3py.py.

7948 def register_relation(self, *relations):
7949 """Register relation as recursive"""
7950 relations = _get_args(relations)
7951 for f in relations:
7952 Z3_fixedpoint_register_relation(self.ctx.ref(), self.fixedpoint, f.ast)
7953
void Z3_API Z3_fixedpoint_register_relation(Z3_context c, Z3_fixedpoint d, Z3_func_decl f)
Register relation as Fixedpoint defined. Fixedpoint defined relations have least-fixedpoint semantics...

◆ rule()

rule ( self,
head,
body = None,
name = None )
Assert rules defining recursive predicates to the fixedpoint solver. Alias for add_rule.

Definition at line 7854 of file z3py.py.

7854 def rule(self, head, body=None, name=None):
7855 """Assert rules defining recursive predicates to the fixedpoint solver. Alias for add_rule."""
7856 self.add_rule(head, body, name)
7857

◆ set()

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

Definition at line 7787 of file z3py.py.

7787 def set(self, *args, **keys):
7788 """Set a configuration option. The method `help()` return a string containing all available options.
7789 """
7790 p = args2params(args, keys, self.ctx)
7791 Z3_fixedpoint_set_params(self.ctx.ref(), self.fixedpoint, p.params)
7792
void Z3_API Z3_fixedpoint_set_params(Z3_context c, Z3_fixedpoint f, Z3_params p)
Set parameters on fixedpoint context.

◆ set_predicate_representation()

set_predicate_representation ( self,
f,
* representations )
Control how relation is represented

Definition at line 7954 of file z3py.py.

7954 def set_predicate_representation(self, f, *representations):
7955 """Control how relation is represented"""
7956 representations = _get_args(representations)
7957 representations = [to_symbol(s) for s in representations]
7958 sz = len(representations)
7959 args = (Symbol * sz)()
7960 for i in range(sz):
7961 args[i] = representations[i]
7962 Z3_fixedpoint_set_predicate_representation(self.ctx.ref(), self.fixedpoint, f.ast, sz, args)
7963
void Z3_API Z3_fixedpoint_set_predicate_representation(Z3_context c, Z3_fixedpoint d, Z3_func_decl f, unsigned num_relations, Z3_symbol const relation_kinds[])
Configure the predicate representation.

◆ sexpr()

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 7984 of file z3py.py.

7984 def sexpr(self):
7985 """Return a formatted string (in Lisp-like format) with all added constraints.
7986 We say the string is in s-expression format.
7987 """
7988 return Z3_fixedpoint_to_string(self.ctx.ref(), self.fixedpoint, 0, (Ast * 0)())
7989
Z3_string Z3_API Z3_fixedpoint_to_string(Z3_context c, Z3_fixedpoint f, unsigned num_queries, Z3_ast queries[])
Print the current rules and background axioms as a string.

◆ statistics()

statistics ( self)
Return statistics for the last `query()`.

Definition at line 7998 of file z3py.py.

7998 def statistics(self):
7999 """Return statistics for the last `query()`.
8000 """
8001 return Statistics(Z3_fixedpoint_get_statistics(self.ctx.ref(), self.fixedpoint), self.ctx)
8002
Z3_stats Z3_API Z3_fixedpoint_get_statistics(Z3_context c, Z3_fixedpoint d)
Retrieve statistics information from the last call to Z3_fixedpoint_query.

◆ to_string()

to_string ( self,
queries )
Return a formatted string (in Lisp-like format) with all added constraints.
   We say the string is in s-expression format.
   Include also queries.

Definition at line 7990 of file z3py.py.

7990 def to_string(self, queries):
7991 """Return a formatted string (in Lisp-like format) with all added constraints.
7992 We say the string is in s-expression format.
7993 Include also queries.
7994 """
7995 args, len = _to_ast_array(queries)
7996 return Z3_fixedpoint_to_string(self.ctx.ref(), self.fixedpoint, len, args)
7997

◆ update_rule()

update_rule ( self,
head,
body,
name )
update rule

Definition at line 7900 of file z3py.py.

7900 def update_rule(self, head, body, name):
7901 """update rule"""
7902 if name is None:
7903 name = ""
7904 name = to_symbol(name, self.ctx)
7905 body = _get_args(body)
7906 f = self.abstract(Implies(And(body, self.ctx), head))
7907 Z3_fixedpoint_update_rule(self.ctx.ref(), self.fixedpoint, f.as_ast(), name)
7908
void Z3_API Z3_fixedpoint_update_rule(Z3_context c, Z3_fixedpoint d, Z3_ast a, Z3_symbol name)
Update a named rule. A rule with the same name must have been previously created.

Field Documentation

◆ ctx

ctx = _get_ctx(ctx)

Definition at line 7771 of file z3py.py.

◆ fixedpoint

fixedpoint = None

Definition at line 7772 of file z3py.py.

◆ vars

vars = []

Definition at line 7778 of file z3py.py.