z3py

问题 Suppose I have a list of 10 variables v = [Real('v_%s' % (i+1)) for i in range(10)] and I want to add a simple constraint like this s = Solver() for i in range(10): s.add(v[i] == i) if s.check() == sat: print(s.model()) So a satisfying model is v_1 = 0, v_2 = 1 .... v_10 = 9 . However the output of print(s.model()) is totoally unordered which makes me confused when I have lots of variables in a bigger model. For this example, the output of my computer is v_5, v_7, v_4, v_2, v_1, v_3, v_6, v_8

问题 Suppose I have a list of 10 variables v = [Real('v_%s' % (i+1)) for i in range(10)] and I want to add a simple constraint like this s = Solver() for i in range(10): s.add(v[i] == i) if s.check() == sat: print(s.model()) So a satisfying model is v_1 = 0, v_2 = 1 .... v_10 = 9 . However the output of print(s.model()) is totoally unordered which makes me confused when I have lots of variables in a bigger model. For this example, the output of my computer is v_5, v_7, v_4, v_2, v_1, v_3, v_6, v_8

问题 Suppose I have a list of 10 variables v = [Real('v_%s' % (i+1)) for i in range(10)] and I want to add a simple constraint like this s = Solver() for i in range(10): s.add(v[i] == i) if s.check() == sat: print(s.model()) So a satisfying model is v_1 = 0, v_2 = 1 .... v_10 = 9 . However the output of print(s.model()) is totoally unordered which makes me confused when I have lots of variables in a bigger model. For this example, the output of my computer is v_5, v_7, v_4, v_2, v_1, v_3, v_6, v_8

问题 I am using Z3py but when I define a array array = Array('array', IntSort(), IntSort()) I don't know how I can to know how many values have the array. 回答1: Arrays in Z3 (and in SMT) are of unbounded size. See, for instance, Create an array with fixed size and initialize it 来源： https://stackoverflow.com/questions/59731478/how-i-can-to-know-how-many-values-have-a-array-in-z3

问题 I am using Z3py but when I define a array array = Array('array', IntSort(), IntSort()) I don't know how I can to know how many values have the array. 回答1: Arrays in Z3 (and in SMT) are of unbounded size. See, for instance, Create an array with fixed size and initialize it 来源： https://stackoverflow.com/questions/59731478/how-i-can-to-know-how-many-values-have-a-array-in-z3

问题 How to generate multiple models for bit vector formula using z3 solver in smt2 format? While implementing IDEA Code for Bit Vector it is generating one model. How to generate all possible models for the same if exists? ex.smt2 file (set-logic QF_BV) (set-info :smt-lib-version 2.0) (declare-const A0 (_ BitVec 16)) (declare-const A1 (_ BitVec 16)) (declare-const A2 (_ BitVec 16)) (declare-const B0 (_ BitVec 16)) (declare-const B1 (_ BitVec 16)) (declare-const B2 (_ BitVec 16)) (declare-const C0

问题 I am using z3py I have a predicate over two integers that needs to be evaluated using a custom algorithm. I have been trying to get it implemented, without much success. Apparently, what I need is a procedural attachment, which is now deprecated. Could anybody tell me how I might impelement this in z3py? I understand that it involves use of Tactics, but I am afraid I haven't managed to figure out how to use them. I wouldn't mind using the deprecated way either, as long as it works. 回答1: There

问题 I was playing with a small multi-objective integer programming problem: In Z3 (using the Python bindings) we can state this very elegantly: from z3 import * x1,x2 = Ints('x1 x2') z1,z2 = Reals('z1 z2') opt = Optimize() opt.set(priority='pareto') opt.add(x1 >= 0, x2 >=0, x1 <= 2, x2 <= 2) opt.add(x1 <= 2*x2) # this version is ok: # opt.add(z1 == x1 - 2*x2, z2 == -x1 + 3*x2) # this truncates coefficients (round down to integer): # opt.add(z1 == 0.5*x1 - 1.0*x2, z2 == -0.5*x1 + 1.5*x2) # this

问题 I want to find a maximal interval in which an expression e is true for all x. A way to write such a formula should be: Exists d : ForAll x in (-d,d) . e and ForAll x not in (-d,d) . !e . To get such a d , the formula f in Z3 (looking at the one above) could be the following: from __future__ import division from z3 import * x = Real('x') delta = Real('d') s = Solver() e = And(1/10000*x**2 > 0, 1/5000*x**3 + -1/5000*x**2 < 0) f = ForAll(x, And(Implies(And(delta > 0, -delta < x, x < delta, x !=

问题 Given a bit vector in Z3 , I am wondering how can I sum up each individual bit of this vector? E.g., a = BitVecVal(3, 2) sum_all_bit(a) = 2 Is there any pre-implemented APIs/functions that support this? Thank you! 回答1: It isn't part of the bit-vector operations. You can create an expression as follows: def sub(b): n = b.size() bits = [ Extract(i, i, b) for i in range(n) ] bvs = [ Concat(BitVecVal(0, n - 1), b) for b in bits ] nb = reduce(lambda a, b: a + b, bvs) return nb print sub(BitVecVal