论文标题
一个有效的基于约束的框架横向浮点SMT问题
An efficient constraint based framework forhandling floating point SMT problems
论文作者
论文摘要
本文介绍了\ us {}的2019版,这是一个新颖的约束编程框架,用于用Smtlib的SMT语言表达的浮点验证问题。 SMT求解器通过将其委派给特定理论(例如,浮点,位向量,数组等)来分解其任务,以推理有关组合或其他复杂约束的任务,SAT编码会累积或无效。这种分解和编码过程导致了高级约束的混淆,以及有关组合模型结构的信息丢失。在\ us {}中,对浮子的约束是第一类对象,目的是揭示和利用浮点域的结构,以增强搜索过程。一个符号阶段将每个SMTLIB实例重写为基本约束,并消除了存在适得其反的辅助变量。搜索中的多元化技术使它脱离了搜索空间无效地区的昂贵枚举。经验评估表明,2019年版的\ us {}在计算具有挑战性的浮点基准上具有竞争力,这些基准即使对于其他CP求解器也可以引起重大搜索工作。它强调,利用推理和搜索的能力至关重要。实际上,它比Colibri产生了3个因子3,并且比SMT求解器快10倍。评估是在214个基准(Griggio Suite)上进行的,该基准是Smtlib中的标准。
This paper introduces the 2019 version of \us{}, a novel Constraint Programming framework for floating point verification problems expressed with the SMT language of SMTLIB. SMT solvers decompose their task by delegating to specific theories (e.g., floating point, bit vectors, arrays, ...) the task to reason about combinatorial or otherwise complex constraints for which the SAT encoding would be cumbersome or ineffective. This decomposition and encoding processes lead to the obfuscation of the high-level constraints and a loss of information on the structure of the combinatorial model. In \us{}, constraints over the floats are first class objects, and the purpose is to expose and exploit structures of floating point domains to enhance the search process. A symbolic phase rewrites each SMTLIB instance to elementary constraints, and eliminates auxiliary variables whose presence is counterproductive. A diversification technique within the search steers it away from costly enumerations in unproductive areas of the search space. The empirical evaluation demonstrates that the 2019 version of \us{} is competitive on computationally challenging floating point benchmarks that induce significant search efforts even for other CP solvers. It highlights that the ability to harness both inference and search is critical. Indeed, it yields a factor 3 improvement over Colibri and is up to 10 times faster than SMT solvers. The evaluation was conducted over 214 benchmarks (The Griggio suite) which is a standard within SMTLIB.