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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 8149 of file z3py.py.

Constructor & Destructor Documentation

◆ __init__()

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

Definition at line 8152 of file z3py.py.

8152 def __init__(self, fixedpoint=None, ctx=None):
8153 assert fixedpoint is None or ctx is not None
8154 self.ctx = _get_ctx(ctx)
8155 self.fixedpoint = None
8156 if fixedpoint is None:
8157 self.fixedpoint = Z3_mk_fixedpoint(self.ctx.ref())
8158 else:
8159 self.fixedpoint = fixedpoint
8160 Z3_fixedpoint_inc_ref(self.ctx.ref(), self.fixedpoint)
8161 self.vars = []
8162
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 8166 of file z3py.py.

8166 def __del__(self):
8167 if self.fixedpoint is not None and self.ctx.ref() is not None and Z3_fixedpoint_dec_ref is not None:
8168 Z3_fixedpoint_dec_ref(self.ctx.ref(), self.fixedpoint)
8169
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 8163 of file z3py.py.

8163 def __deepcopy__(self, memo={}):
8164 return FixedPoint(self.fixedpoint, self.ctx)
8165

◆ __iadd__()

__iadd__ ( self,
fml )

Definition at line 8202 of file z3py.py.

8202 def __iadd__(self, fml):
8203 self.add(fml)
8204 return self
8205

◆ __repr__()

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

Definition at line 8363 of file z3py.py.

8363 def __repr__(self):
8364 """Return a formatted string with all added rules and constraints."""
8365 return self.sexpr()
8366

◆ abstract()

abstract ( self,
fml,
is_forall = True )

Definition at line 8400 of file z3py.py.

8400 def abstract(self, fml, is_forall=True):
8401 if self.vars == []:
8402 return fml
8403 if is_forall:
8404 return ForAll(self.vars, fml)
8405 else:
8406 return Exists(self.vars, fml)
8407
8408

◆ add()

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

Definition at line 8198 of file z3py.py.

8198 def add(self, *args):
8199 """Assert constraints as background axioms for the fixedpoint solver. Alias for assert_expr."""
8200 self.assert_exprs(*args)
8201

◆ 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 8325 of file z3py.py.

8325 def add_cover(self, level, predicate, property):
8326 """Add property to predicate for the level'th unfolding.
8327 -1 is treated as infinity (infinity)
8328 """
8329 Z3_fixedpoint_add_cover(self.ctx.ref(), self.fixedpoint, level, predicate.ast, property.ast)
8330
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 8214 of file z3py.py.

8214 def add_rule(self, head, body=None, name=None):
8215 """Assert rules defining recursive predicates to the fixedpoint solver.
8216 >>> a = Bool('a')
8217 >>> b = Bool('b')
8218 >>> s = Fixedpoint()
8219 >>> s.register_relation(a.decl())
8220 >>> s.register_relation(b.decl())
8221 >>> s.fact(a)
8222 >>> s.rule(b, a)
8223 >>> s.query(b)
8224 sat
8225 """
8226 if name is None:
8227 name = ""
8228 name = to_symbol(name, self.ctx)
8229 if body is None:
8230 head = self.abstract(head)
8231 Z3_fixedpoint_add_rule(self.ctx.ref(), self.fixedpoint, head.as_ast(), name)
8232 else:
8233 body = _get_args(body)
8234 f = self.abstract(Implies(And(body, self.ctx), head))
8235 Z3_fixedpoint_add_rule(self.ctx.ref(), self.fixedpoint, f.as_ast(), name)
8236
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 8206 of file z3py.py.

8206 def append(self, *args):
8207 """Assert constraints as background axioms for the fixedpoint solver. Alias for assert_expr."""
8208 self.assert_exprs(*args)
8209

◆ assert_exprs()

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

Definition at line 8184 of file z3py.py.

8184 def assert_exprs(self, *args):
8185 """Assert constraints as background axioms for the fixedpoint solver."""
8186 args = _get_args(args)
8187 s = BoolSort(self.ctx)
8188 for arg in args:
8189 if isinstance(arg, Goal) or isinstance(arg, AstVector):
8190 for f in arg:
8191 f = self.abstract(f)
8192 Z3_fixedpoint_assert(self.ctx.ref(), self.fixedpoint, f.as_ast())
8193 else:
8194 arg = s.cast(arg)
8195 arg = self.abstract(arg)
8196 Z3_fixedpoint_assert(self.ctx.ref(), self.fixedpoint, arg.as_ast())
8197
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 8391 of file z3py.py.

8391 def declare_var(self, *vars):
8392 """Add variable or several variables.
8393 The added variable or variables will be bound in the rules
8394 and queries
8395 """
8396 vars = _get_args(vars)
8397 for v in vars:
8398 self.vars += [v]
8399

◆ fact()

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

Definition at line 8241 of file z3py.py.

8241 def fact(self, head, name=None):
8242 """Assert facts defining recursive predicates to the fixedpoint solver. Alias for add_rule."""
8243 self.add_rule(head, None, name)
8244

◆ get_answer()

get_answer ( self)
Retrieve answer from last query call.

Definition at line 8292 of file z3py.py.

8292 def get_answer(self):
8293 """Retrieve answer from last query call."""
8294 r = Z3_fixedpoint_get_answer(self.ctx.ref(), self.fixedpoint)
8295 return _to_expr_ref(r, self.ctx)
8296
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 8359 of file z3py.py.

8359 def get_assertions(self):
8360 """retrieve assertions that have been added to fixedpoint context"""
8361 return AstVector(Z3_fixedpoint_get_assertions(self.ctx.ref(), self.fixedpoint), self.ctx)
8362
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 8318 of file z3py.py.

8318 def get_cover_delta(self, level, predicate):
8319 """Retrieve properties known about predicate for the level'th unfolding.
8320 -1 is treated as the limit (infinity)
8321 """
8322 r = Z3_fixedpoint_get_cover_delta(self.ctx.ref(), self.fixedpoint, level, predicate.ast)
8323 return _to_expr_ref(r, self.ctx)
8324
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 8297 of file z3py.py.

8297 def get_ground_sat_answer(self):
8298 """Retrieve a ground cex from last query call."""
8299 r = Z3_fixedpoint_get_ground_sat_answer(self.ctx.ref(), self.fixedpoint)
8300 return _to_expr_ref(r, self.ctx)
8301

◆ get_num_levels()

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

Definition at line 8314 of file z3py.py.

8314 def get_num_levels(self, predicate):
8315 """Retrieve number of levels used for predicate in PDR engine"""
8316 return Z3_fixedpoint_get_num_levels(self.ctx.ref(), self.fixedpoint, predicate.ast)
8317
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 8306 of file z3py.py.

8306 def get_rule_names_along_trace(self):
8307 """retrieve rule names along the counterexample trace"""
8308 # this is a hack as I don't know how to return a list of symbols from C++;
8309 # obtain names as a single string separated by semicolons
8310 names = _symbol2py(self.ctx, Z3_fixedpoint_get_rule_names_along_trace(self.ctx.ref(), self.fixedpoint))
8311 # split into individual names
8312 return names.split(";")
8313

◆ get_rules()

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

Definition at line 8355 of file z3py.py.

8355 def get_rules(self):
8356 """retrieve rules that have been added to fixedpoint context"""
8357 return AstVector(Z3_fixedpoint_get_rules(self.ctx.ref(), self.fixedpoint), self.ctx)
8358
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 8302 of file z3py.py.

8302 def get_rules_along_trace(self):
8303 """retrieve rules along the counterexample trace"""
8304 return AstVector(Z3_fixedpoint_get_rules_along_trace(self.ctx.ref(), self.fixedpoint), self.ctx)
8305

◆ help()

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

Definition at line 8176 of file z3py.py.

8176 def help(self):
8177 """Display a string describing all available options."""
8178 print(Z3_fixedpoint_get_help(self.ctx.ref(), self.fixedpoint))
8179
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 8210 of file z3py.py.

8210 def insert(self, *args):
8211 """Assert constraints as background axioms for the fixedpoint solver. Alias for assert_expr."""
8212 self.assert_exprs(*args)
8213

◆ param_descrs()

param_descrs ( self)
Return the parameter description set.

Definition at line 8180 of file z3py.py.

8180 def param_descrs(self):
8181 """Return the parameter description set."""
8182 return ParamDescrsRef(Z3_fixedpoint_get_param_descrs(self.ctx.ref(), self.fixedpoint), self.ctx)
8183
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 8351 of file z3py.py.

8351 def parse_file(self, f):
8352 """Parse rules and queries from a file"""
8353 return AstVector(Z3_fixedpoint_from_file(self.ctx.ref(), self.fixedpoint, f), self.ctx)
8354
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 8347 of file z3py.py.

8347 def parse_string(self, s):
8348 """Parse rules and queries from a string"""
8349 return AstVector(Z3_fixedpoint_from_string(self.ctx.ref(), self.fixedpoint, s), self.ctx)
8350
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 8245 of file z3py.py.

8245 def query(self, *query):
8246 """Query the fixedpoint engine whether formula is derivable.
8247 You can also pass an tuple or list of recursive predicates.
8248 """
8249 query = _get_args(query)
8250 sz = len(query)
8251 if sz >= 1 and isinstance(query[0], FuncDeclRef):
8252 _decls = (FuncDecl * sz)()
8253 i = 0
8254 for q in query:
8255 _decls[i] = q.ast
8256 i = i + 1
8257 r = Z3_fixedpoint_query_relations(self.ctx.ref(), self.fixedpoint, sz, _decls)
8258 else:
8259 if sz == 1:
8260 query = query[0]
8261 else:
8262 query = And(query, self.ctx)
8263 query = self.abstract(query, False)
8264 r = Z3_fixedpoint_query(self.ctx.ref(), self.fixedpoint, query.as_ast())
8265 return CheckSatResult(r)
8266
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 8267 of file z3py.py.

8267 def query_from_lvl(self, lvl, *query):
8268 """Query the fixedpoint engine whether formula is derivable starting at the given query level.
8269 """
8270 query = _get_args(query)
8271 sz = len(query)
8272 if sz >= 1 and isinstance(query[0], FuncDecl):
8273 _z3_assert(False, "unsupported")
8274 else:
8275 if sz == 1:
8276 query = query[0]
8277 else:
8278 query = And(query)
8279 query = self.abstract(query, False)
8280 r = Z3_fixedpoint_query_from_lvl(self.ctx.ref(), self.fixedpoint, query.as_ast(), lvl)
8281 return CheckSatResult(r)
8282

◆ reason_unknown()

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

Definition at line 8386 of file z3py.py.

8386 def reason_unknown(self):
8387 """Return a string describing why the last `query()` returned `unknown`.
8388 """
8389 return Z3_fixedpoint_get_reason_unknown(self.ctx.ref(), self.fixedpoint)
8390
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 8331 of file z3py.py.

8331 def register_relation(self, *relations):
8332 """Register relation as recursive"""
8333 relations = _get_args(relations)
8334 for f in relations:
8335 Z3_fixedpoint_register_relation(self.ctx.ref(), self.fixedpoint, f.ast)
8336
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 8237 of file z3py.py.

8237 def rule(self, head, body=None, name=None):
8238 """Assert rules defining recursive predicates to the fixedpoint solver. Alias for add_rule."""
8239 self.add_rule(head, body, name)
8240

◆ set()

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

Definition at line 8170 of file z3py.py.

8170 def set(self, *args, **keys):
8171 """Set a configuration option. The method `help()` return a string containing all available options.
8172 """
8173 p = args2params(args, keys, self.ctx)
8174 Z3_fixedpoint_set_params(self.ctx.ref(), self.fixedpoint, p.params)
8175
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 8337 of file z3py.py.

8337 def set_predicate_representation(self, f, *representations):
8338 """Control how relation is represented"""
8339 representations = _get_args(representations)
8340 representations = [to_symbol(s) for s in representations]
8341 sz = len(representations)
8342 args = (Symbol * sz)()
8343 for i in range(sz):
8344 args[i] = representations[i]
8345 Z3_fixedpoint_set_predicate_representation(self.ctx.ref(), self.fixedpoint, f.ast, sz, args)
8346
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 8367 of file z3py.py.

8367 def sexpr(self):
8368 """Return a formatted string (in Lisp-like format) with all added constraints.
8369 We say the string is in s-expression format.
8370 """
8371 return Z3_fixedpoint_to_string(self.ctx.ref(), self.fixedpoint, 0, (Ast * 0)())
8372
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 8381 of file z3py.py.

8381 def statistics(self):
8382 """Return statistics for the last `query()`.
8383 """
8384 return Statistics(Z3_fixedpoint_get_statistics(self.ctx.ref(), self.fixedpoint), self.ctx)
8385
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 8373 of file z3py.py.

8373 def to_string(self, queries):
8374 """Return a formatted string (in Lisp-like format) with all added constraints.
8375 We say the string is in s-expression format.
8376 Include also queries.
8377 """
8378 args, len = _to_ast_array(queries)
8379 return Z3_fixedpoint_to_string(self.ctx.ref(), self.fixedpoint, len, args)
8380

◆ update_rule()

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

Definition at line 8283 of file z3py.py.

8283 def update_rule(self, head, body, name):
8284 """update rule"""
8285 if name is None:
8286 name = ""
8287 name = to_symbol(name, self.ctx)
8288 body = _get_args(body)
8289 f = self.abstract(Implies(And(body, self.ctx), head))
8290 Z3_fixedpoint_update_rule(self.ctx.ref(), self.fixedpoint, f.as_ast(), name)
8291
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 8154 of file z3py.py.

◆ fixedpoint

fixedpoint = None

Definition at line 8155 of file z3py.py.

◆ vars

vars = []

Definition at line 8161 of file z3py.py.