smt

问题 What is the unit in which memory usage is measured in z3 statistics? Is it MB or KB? And what does the memory exactly means? Is it the maximum memory usage or the aggregate sum of all allocations during the execution? 回答1: It's an approximation of the maximum heap size during execution and it is added to the statistics object through the following function in cmd_context.cpp: void cmd_context::display_statistics(...) { statistics st; ... unsigned long long mem = memory::get_max_used_memory();

问题 I am just starting to use Z3 (v4.4.0), and I wanted to try one of the tutorial examples : (declare-const a Int) (assert (> (* a a) 3)) (check-sat) (get-model) (echo "Z3 will fail in the next example...") (declare-const b Real) (declare-const c Real) (assert (= (+ (* b b b) (* b c)) 3.0)) (check-sat) As said, the second example fails with "unknown", and by increasing the verbose level (to 3) I think I understand why : some problem with the simplifying process, then the tactic fails. In order

问题 I'm a total newbie with Z3 (started today). So far liking it a lot. Great tool. Unfortunately the syntax confuses me a bit. I want to prove that if: a^3 = x y z = m ( with a, x, y, z, m (0..1) ) then: 3a <= (x+y+z) I do so by trying to find a model satisfying that: 3a > (x+y+z) Here is the Z3 code: (declare-const a Real) (declare-const x Real) (declare-const y Real) (declare-const z Real) (declare-const m Real) (assert (> a 0)) (assert (< a 1)) (assert (> x 0)) (assert (< x 1)) (assert (> y 0

问题 I've been looking at various SMT solvers, mainly Z3, CVC4, and VeriT. They all have vague descriptions of their ability to solve SMT problems with quantifiers. Their documentation is primarily example based (Z3), or consists of academic papers, describing possible changes that may or may not actually be implemented. I know that there are decidable fragments of First-order logic, such as: Finitely-bounded quantifiers Monadic first-order logic What I'd like to know is, which (if any) classes of

问题 Say I have t1<x and x<t2 is it possible to hide variable x so that t1<t2 in Z3? 回答1: You can use quantifier elimination for doing that. Here is an example: (declare-const t1 Int) (declare-const t2 Int) (elim-quantifiers (exists ((x Int)) (and (< t1 x) (< x t2)))) You can try this example online at: http://rise4fun.com/Z3/kp0X 回答2: Possible solution using Redlog of Reduce: 来源： https://stackoverflow.com/questions/11625388/how-to-hide-variable-with-z3

问题 I'm looking at doing some verification work where I've got regular tree grammars as an underlying theory. Z3 lets you define your own stuff with uninterpreted functions, but that doesn't tend to work well any time your decision procedures are recursive. They used to allow for plugins but that has been depricated, I think. I'm wondering, does anybody have a recommendation of a decent SMT solver that allows you to write decision procedures for custom theories? 回答1: There are several options

问题 I am experimenting with Z3 where I combine the theories of arithmetic, quantifiers and equality. This does not seem to be very efficient, in fact it seems to be more efficient to replace the quantifiers with all instantiated ground instances when possible. Consider the following example, in which I have encoded the unique names axiom for a function f that takes two arguments of sort Obj and returns an interpreted sort S . This axiom states that each unique list of arguments to f returns a

问题 Does the Hyper Threading allow to use of L1-cache to exchange the data between the two threads, which are executed simultaneously on a single physical core, but in two virtual cores? With the proviso that both belong to the same process, i.e. in the same address space. Page 85 (2-55) - Intel® 64 and IA-32 Architectures Optimization Reference Manual : http://www.intel.com/content/dam/www/public/us/en/documents/manuals/64-ia-32-architectures-optimization-manual.pdf 2.5.9 Hyper-Threading

问题 I have tried several SMT solvers (CVC3, CVC4 and Z3) on the following seemingly trivial benchmark: (set-logic LIA) (set-info :smt-lib-version 2.0) (assert (forall (( x Int)) (forall ((y Int)) (= y x)))) (check-sat) (exit) The solvers all return unknown. I understand that this is an undecidable fragment (well non-linear) but I was expecting there would be some simple instantiation heuristics that could solve it. I also tried adding some extra assertions with constants but it didn't help. Is

问题 I am not sure that this is possible using SMT-LIB, if it is not possible does an alternative solver exist that can do it? Consider the equations a < 10 and a > 5 b < 5 and b > 0 b < c < a with a , b and c integers The values for a and b where the maximum number of model exist that satisfy the equations when a=9 and b=1 . Do SMT-LIB support the following: For each values of a and b count the number of models that satisfy the formulas and give the value for a and b that maximize the count. 回答1: