A softwarereconfigurable hardware sat solver abstract. Tsp is another npcomplete problem, but the transformations are most often much more difficult. Acceleration of satisfiability algorithms by reconfigurable hardware. Pdf the majority of the existing reconfigurable hardware sat solvers employ some variation of the davisputnam algorithm. An approach for solving large sat problems on fpga acm. We present a practical fpgabased accelerator for solving boolean satisfiability problems sat. The whole execution is done in hardware eliminating any runtime communication with the host processor. A massivelyparallel easilyscalable satisfiability solver.
It may be said that the sat solver includes a plurality of state machines, each corresponding to only one of a plurality of variables in a boolean sat problem. To make a long story short, a sat solver is something you give a boolean formula to, and it tells you whether it can find a value for the different variables such that the formula is true. The algorithm has no complex heuristic, and it only depends on the concepts of preprocessing technology, probability distribution and centralized search. A practical reconfigurable hardware accelerator for. Each negated clause is viewed as a cube in the ndimensional boolean search space denoting a subspace where no satisfying assignments can be found. Using genetic algorithms for hardware core placement and. Hardware acceleration for boolean satisfiability solver by. In previous work, a basic hw sat solver 3 has been developed as a veri. The principal difference when compared to using ordinary microprocessors is the ability to make substantial changes to the.
Oct 05, 2004 a sat solver using reconfigurable hardware and virtual logic our main contributions include new forms of massive finegrain parallelism, structured design techniques based on iterative logic arrays that reduce compilation times from hours to minutes, and a decomposition technique that creates independent subproblems that may be concurrently. If i start a free software project, then i should use a free software. A fast sat solver algorithm best suited to reconfigurable. We present an fpgabased hardware solution to the boolean satisfiability sat problem, with the main goals of scalability and speedup. The analysis and classification of existing systems has been performed according to such criteria as algorithmic issues, reconfiguration modes, the execution model, the programming model, logic capacity, and performance. Solving sat with a contextswitching virtual clause pipeline. The virtual circuit is an arbitrarily large clause pipeline, partitioned into sections of a number of stages hardware pages, which can fit in the. The goal of this thesis is to explore and compare implementation of control algorithms on reconfigurable logic. Darpa selects teams to unleash power of specialized. We have proposed a novel sat solver based on an improved local search algorithm on the reconfigurable hardware platform. An effective probability distribution sat solver on reconfigurable hardware abstract.
Abstractthis paper introduces a novel approach for solving the boolean satisfiability sat problem by combining software and configurable hardware. Let us agree to consider such nary trees n2 for which n is a power of 2, i. Computation may be colocated with the bram memory, taking. My case split is based on a tree like structure, where every branch is t. Cube subtraction systematically subtracts all clausecubes from the universal cube. In this paper, we present the architecture of a new sat solver using reconfigurable logic. We present a reconfigurable sat solver architecture that exploits the fine granularity and massive parallelism of fpgas to evaluate the sat formula. Software can make use of state of the art processors built with the.
Modern boolean sat solvers are a critical component of many innovative techniques in security, software engineering, hardware veri cation, and ai such as solver based automated testing with symbolic execution 9, bounded model checking 11 for software and hardware veri cation, and planning in ai 27 respectively. An fpgabased sat solver architecture with nearzero synthesis and layout overhead abstract in this work we have developed a completely new and novel sat solver architecture to address three fundamental hurdles blocking the way to a wider application of reconfigurable hardware based acceleration of sat, namely, 1 the time. An algorithm implemented directly in the hardware, can execute it faster, because the only instruction that has to make is execute the algorithm. A sat solver using reconfigurable hardware and virtual logic. The solvers are used in software verification, hardware verification and testing, ai planning, routing, etc. Specifically, the presented approach shows very strong performance on the class of small, but difficult sat problems with speedups between 89828x over minisat and 599x over. A second mapping is executed for placing the modules that belong to specific configurations. If i like free software, then i should start a free software project.
Fpgabased implementation of genetic algorithm for the traveling salesman problem and its industrial application. The new software preprocessing procedure and hardware architecture are involved to solve largescale sat problems instances. Some potential strategies and technologies that can help overcome these challenges are examined here. Implementation of the advanced sat search techniques in. Unlike previous efforts for hardware accelerated sat solving, our design focuses on accelerating the most time consuming part of the sat solver boolean constraint propagation bcp, leaving the choices of heuristics such as branching order, restarting policy, and learning and backtracking to.
With this algorithm, the sat solver can be accelerated by hardware. The use of hardware sat solver only makes sense if there is significant performance advantage compared to software. By now, many such highperformance sat solvers exist. Sdh will develop runtime reconfigurable hardware and software that enables near fullcustom performance without sacrificing programmability for dataintensive algorithms, enabling efficient processing implementations with a single architecture and shared software. Example suppose that a, b and c are boolean variables, and you want to know if these variables can be assigned a value that somehow makes the formula a. In our approach the traversal of the implication graph as well as conflict clause generation are performed in hardware, in parallel. Us81660b2 reconfigurable hardware accelerator for boolean. Highlevel strategy outline vocabulary and preliminaries basic algorithm boolean constraint propagation con ict analysis highlevel strategy reading sol swords basics of sat solving algorithms. Satisfiability sat is a computationally expensive algorithm central to many cad and test applications. The suggested technique avoids instancespecific hardware compilation and, as a result, allows the total problem solving time to be reduced compared. Introduction the satisfiability sat problem given a boolean formula, find an assignment of binary values to a subset of the variables, so that f is set to 1, or prove that no such. An effective probability distribution sat solver on. Our experiment results show that time complexity does not increase with the size of sat problems and the proposed method can achieve at least 30x speedup compared. Unlike previous efforts for hardware accelerated sat solving, our design focuses on accelerating the most time consuming part of the sat solver boolean constraint propagation bcp, leaving the choices of heuristics such as branching order, restarting policy, and learning and.
Software can make use of state of the art processors built with the latest processor technology. The paper describes two methods for the design of matrixoriented sat solvers based on data compression. Citeseerx a hardwaresoftware approach to accelerate. Fpgabased hardware acceleration for boolean satisfiability. The boolean satisfiability sat problem is the key problem in computer theory and application. Decision heuristic for davis putnam, loveland and logemann. The first one provides matrix compression in a host computer and decompression in an fpga. Through constraining the initial assignments of the variables. Checking that one finitestate system refines implements another 12 phase transitions in k sat consider a fixedlength clause model k sat means that each clause contains exactly k literals let sat problem comprise m clauses and n variables randomly generate the problem for fixed k and varying m and n. Each of the plurality of ordered variables has a corresponding one of a plurality of state machines. Multivariate polynomial interpolation is a key computation in many areas of science and engineering and, in our case, is crucial for the solution of the reverse engineering of genetic networks modeled by finite fields.
Ma kefan,xiao liquan,zhang jianmin accelerating an fpgabased sat solver by software and hardware codesignj. In section ii, the sat problem is described in detail. This paper proposes an architecture that combines a contextswitching virtual configware software sat solver with an embedded processor to promote a tighter coupling between configware and software. Ieee transactions on very large scale integration vlsi. Wsat and its variants are one of the best performing stochastic local search algorithms for the satisfiability sat problem. Sep 30, 2003 special attention was given to the boolean satisfiability sat problem resulting in a considerable number of different architectures being proposed.
Hardware accelerated sat solversa survey sciencedirect. Sat problem with the aid of reconfigurable hardware 45, 912, 1422. I am implementing a sat solver based on dpll algorithm, and it works fine on small formulas and larger satisfiable problems. Firstly, a genetic algorithm is used for placing modules of the base mapping. In this paper, we present a reconfigurable hardware sat solver that performs a search algorithm combining the advanced techniques. Using field programmable gate array fpga, it is possible to solve ordinary differential equations ode at high speed. The application software program is passed to the profiler where the potential hardware candidates are identified. Hardwaresoftware implementation of fpgatargeted matrix. Thus far, the current state of hardware and software sat solvers has been addressed, as well as the challenges posed when developing an effective reconfigurable sat solver. Mar 14, 2000 the novel backtracking approach for the reconfigurable hardware sat solver will now be explained in another way. The approach to solving the hardware software partitioning problem is shown in fig.
However, the level of sophistication of software solvers overcame their hardware counterparts, which remained limited to smaller problem instances. Isat technology indirectly reaches our everyday life. A practical reconfigurable hardware accelerator for boolean. Given a conjunctive normal form with three literals per clause, the problem is to determine whether there exists a truth assignment to the variables so that each clause has exactly one true literal and thus exactly two false literals. A variant of the 3satisfiability problem is the oneinthree 3 sat also known variously as 1in3 sat and exactly1 3 sat. A software simulator is implemented to verify the proposed algorithm and the performance improvement is estimated. A sat solver using software and reconfigurable hardware. A parallel sat solver using a reconfigurable processor is described in 9. Reconfigurable hardware implementation of a multivariate. Salem, hardware based algorithm for conflict diagnosis in sat solver, proceedings of the ieee acs international conference on computer systems and applications aiccsa 2008.
Designing an efficient hardware implication accelerator for. Block ram bram may be used to store sat instance information. Acceleration of satisfiability algorithms by reconfigurable. Each state machine has an implication circuit for its respective variable, and operates in parallel according to an identical state machine. Boolean satisfiability, reconfigurable hardware, software reconfigurable hardware partitioning 1 introduction during the last eight years a great deal of research effort was aimed at the implementation of efficient boolean satisfiability sat solvers on the basis of reconfigurable hardware in fpga, in particular. Due to the constant improvements of software sat solvers on branching, learning and restarting heuristics, it is impossible to completely map a software sat solver into hardware and build a practical hardware sat solver, as previously attempted e. The suggested technique avoids instancespecific hardware compilation and, as a result, allows the total problem solving time to be. The satisfier suggested uses an applicationspecific approach, thus an instancespecific hardware compilation is completely avoided. Since names have not typically been given to hardware sat satisfiers, we will refer to them according to the first authors names of the respective publications. Use a good tradeo between speed and completeness i boolean constraint propagation with watched literals i typically about 80% of sat solver runtime. On the basis of this algorithm a software reconfigurable hardware sat solver was designed, implemented and compared to a similar. In an implementation, branching, restarting, and conflict analysis may be left to the software on the host cpu. Any algorithm in hardware is faster than in software.
After backtracking, some variables are unassigned, and the current decision level is decreased accordingly. Besides new algorithms and better heuristics, refined implementation techniques turned out to be vital for this success. Implementation of an algorithm in specific hardware. An example system offloads 80 to 90 percent of the software sat solver s computation. But when someone talk about of the software implementation of an algorithm is for say that only use the processor. In this article, we propose an approach for solving large 3 sat.
Designs based on field programmable gate arrays fpgas have been described in 234567, and were compared in a survey 8. Initially, reconfigurable hardware tools provided a promising avenue to accelerating sat solving over traditional software based solutions. A softwarereconfigurable hardware sat solver 409 the remainder of this paper is organized as follows. Hardwaresoftware codesign, acceleration and prototyping. Contribute to irifrancegini development by creating an account on github. So, yes, sat can be used for all these problems you are mentioning. Learning rate based branching heuristic for sat solvers. This paper introduces a novel approach for solving the boolean satisfiability sat problem by combining software and configurable hardware.
The suggested technique avoids instancespecific hardware compilation and, as a result, achieves a higher performance than pure software approaches. Moreover, it permits problems that exceed the resources of the available reconfigurable hardware to be solved. A shift register based clause evaluator for reconfigurable. A practical reconfigurable hardware accelerator for boolean satisfiability solvers. The area of sat solving has seen tremendous progress over the last years. Algorithm design while the gs method for solving systems of nonlinear equations is generally well suited to implementation on an fpga, it is not generally stated in a form that is ideally suited to reconfigurable hardware. A softwarereconfigurable hardware sat solver article pdf available in ieee transactions on very large scale integration vlsi systems 124. This paper proposes a new algorithm for solving the boolean satisfiability sat problem.
Other algorithms are proposed for realtime mapping. The study proposes a new decision heuristic for davis putnam, loveland and logemann algorithm dpllbased satisfiability sat solvers based on cube subtraction. A hardware accelerator is provided for boolean constraint propagation bcp using fieldprogrammable gate arrays fpgas for use in solving the boolean satisfiability problem sat. This paper presents the stateoftheart in reconfigurable hardware sat satisfiers. This cited by count includes citations to the following articles in scholar. Oct 08, 2009 thus, the bcp part of the sat solving process may be accelerated in hardware. We present a design tool flow and prototype implementation of an instancespecific satisfiability solver and discuss experimental results. The conceptual simplicity of sat facilitates algorithm development, and signi cant research and engineering e orts have led to sophisticated algorithms with highlyoptimized implementations. This paper presents a hardware implementation of the probsat algorithm using highlevel synthesis hls for rapid porting of the design from the original c implementation.
While the general sat problem is np complete, advanced solver algorithms and heuristics can provide fast and efficient solving of otherwise. Us6038392a implementation of boolean satisfiability with. Reconfigurable computing is a computer architecture combining some of the flexibility of software with the high performance of hardware by processing with very flexible high speed computing fabrics like fieldprogrammable gate arrays fpgas. A boolean sat solver uses reconfigurable hardware to solve a specific input problem. Faster implementations of such algorithms are needed to cope with the increasing quantity and complexity of genetic data. Genetic algorithm driven hardwaresoftware partitioning. Hardware approaches to systematic search procedures for sat problems are beyond the scope of this paper. Special attention was given to the boolean satisfiability sat problem resulting in a considerable number of different architectures being proposed. Imost companies doing software or hardware veri cation are now using sat solvers. The boolean satisfiability problem sat consists in. Us12099,160 20080408 20080408 reconfigurable hardware accelerator for boolean satisfiability solver active 20310105 us81660b2 en priority applications 1 application number. Sol swords basics of sat solving algorithms december 8, 2008 20 24. An effective fpga solver on probability distribution and.542 1061 1188 643 1207 780 454 822 988 85 95 1074 1528 1233 403 1105 435 247 907 969 1265 588 35 403 504 1481 1040 928 1541 987 637 713 713 1392 696 883 1176 973 616 1089