z3py

问题 I have a DataFrame as follows : Name Volatility Return a 0.0243 0.212 b 0.0321 0.431 c 0.0323 0.443 d 0.0391 0.2123 e 0.0433 0.3123 I'd like to have a Volatility of 0.035 and the maximized Return for that volatility. That is, I'd like, in a new Df the Name and the percentage of that asset that will be in my portfolio that gives the maximum Return for a Volatility equals to 0.035 . Therefore, I need to solve a system of equations with multiple conditions, to obtain the best solution (Highest

问题 I need to print an entire Z3 problem to debug it, but when I print it the output is truncated. from z3 import * s = Solver() ... Add many assertions to s ... print(s) How do I display everything? 回答1: Try: set_option(max_args=10000000, max_lines=1000000, max_depth=10000000, max_visited=1000000) You might want to play with actual values to come up with something that suits your needs. 来源： https://stackoverflow.com/questions/62008181/turning-off-z3py-print-truncation

问题 I've been skimming through the documentation of Z3Py and for the likes of me have not been able to figure out how to get the proof from a Solver (E.g. if I start from an instance of De Morgan's Laws how can I extract the proof from Z3Py of the instance, step by step). The only reference I saw was for proof(self) in the Solver class which supposedly gets the proof of the last check if proof construction is enabled, but I keep getting back the very vague error: Traceback (most recent call last)

问题 I've been skimming through the documentation of Z3Py and for the likes of me have not been able to figure out how to get the proof from a Solver (E.g. if I start from an instance of De Morgan's Laws how can I extract the proof from Z3Py of the instance, step by step). The only reference I saw was for proof(self) in the Solver class which supposedly gets the proof of the last check if proof construction is enabled, but I keep getting back the very vague error: Traceback (most recent call last)

问题 Probably a basic question related to Z3: i am trying to get all solutions of a boolean expression, e.g. for a OR b , i want to get {(true, true),(false,true),(true,false)} Based on other responses found, e.g. Z3: finding all satisfying models, i have the following code: a = Bool('a') b = Bool('b') f1=Or(a,b) s=Solver() s.add(f1) while s.check() == sat: print s s.add(Not(And(a == s.model()[a], b == s.model()[b]))) The issue is that it enters an infinite loop as at the second iteration: the

问题 How can I convert a z3.String to a sequence of ASCII values? For example, here is some code that I thought would check whether the ASCII values of all the characters in the string add up to 100: import z3 def add_ascii_values(password): return sum(ord(character) for character in password) password = z3.String("password") solver = z3.Solver() ascii_sum = add_ascii_values(password) solver.add(ascii_sum == 100) print(solver.check()) print(solver.model()) Unfortunately, I get this error:

问题 I have tried to implement Floor and Ceiling Function as defined in the following link https://math.stackexchange.com/questions/3619044/floor-or-ceiling-function-encoding-in-first-order-logic/3619320#3619320 But Z3 query returning counterexample. Floor Function _X=Real('_X') _Y=Int('_Y') _W=Int('_W') _n=Int('_n') _Floor=Function('_Floor',RealSort(),IntSort()) .. _s.add(_X>=0) _s.add(_Y>=0) _s.add(Implies(_Floor(_X)==_Y,And(Or(_Y==_X,_Y<_X),ForAll(_W,Implies(And(_W>=0,_W<_X),And(_W ==_Y,_W<_Y))

问题 How do you set a timeout for the z3 optimizer such that it will give you the best known solution when it runs out of time? from z3 import * s = Optimize() # Hard Problem print(s.check()) print(s.model()) Follow-up question, can you set z3 to randomized hill climbing or does it always perform a complete search? 回答1: Long answer short, you can't . That's simply not how the optimizer works. That is, it doesn't find a solution and then try to improve it. If you interrupt it or set a time-out,

问题 How do you set a timeout for the z3 optimizer such that it will give you the best known solution when it runs out of time? from z3 import * s = Optimize() # Hard Problem print(s.check()) print(s.model()) Follow-up question, can you set z3 to randomized hill climbing or does it always perform a complete search? 回答1: Long answer short, you can't . That's simply not how the optimizer works. That is, it doesn't find a solution and then try to improve it. If you interrupt it or set a time-out,

问题 I'm currently trying to solve some equation with z3python, and I am coming across a situation I could not deal with. I need to xor certain BitVecs with specific non ascii char values, and sum them up to check a checksum. Here is an example : pbInput = [BitVec("{}".format(i), 8) for i in range(KEY_LEN)] password = "\xff\xff\xde\x8e\xae" solver.add(Xor(pbInput[0], password[0]) + Xor(pbInput[3], password[3]) == 300) It results in a z3 type exception : z3.z3types.Z3Exception: Value cannot be