9 results about "Conjunctive normal form" patented technology

A database system is operable to determine a query for execution. A disjunction of a plurality of conjunctive normal form (CNF) filtering predicates is determined based on filtering predicates of the query. An IO pipeline is generated based on the disjunction of the plurality of CNF filtering predicates that includes, based on applying at least one type of optimization, at least one shared IO element common to multiple ones of plurality of the CNF filtering predicates. The IO pipeline is executed in accordance with execution of the query to generate a filtered subset of a plurality of rows that each meet at least one of the plurality of CNF filtering predicates.

The invention relates to the field of computer science and technology and artificial intelligence, and particularly discloses a MaxSAT initial assignment method based on an improved Johnson algorithm. The maximum satisfiability problem (MaxSAT) is an optimized version of the Boolean satisfiability problem (SAT). The invention provides a new heuristic initial assignment generation method aiming at the problem of low search efficiency caused by the adoption of a complete random initialization strategy by an existing local search solver. The method is realized through the following technical scheme: firstly, inputting a conjunctive normal form of a MaxSAT problem, calculating positive and negative character scores of each variable based on a Johnson algorithm principle, and further obtaining probability estimation that each variable is assigned to be true; then, a threshold value is set to carry out deterministic assignment on the high-confidence-coefficient variable, and an assignment result is propagated in time to simplify a problem structure; iteratively executing calculation, assignment and propagation processes until a preset cycle cut-off condition is reached; and finally, performing probabilistic complementation on the residual variables to generate a complete initial assignment.

The invention provides a method and a system for searching a password difference feature based on a weight construction SAT model. The method and the system mainly solve the problems that more Boolean variables are introduced and the efficiency of searching the password difference feature is low when an S box probability is described in the prior art. According to the implementation scheme, the method comprises the steps that a linear component of a target cryptographic algorithm is converted into a linear differential propagation assembly; according to DDT of a target algorithm S box, Boolean variables are introduced, weights are given, impossible propagation clauses are generated and simplified, and an S box differential propagation component in the SAT model is obtained; establishing an objective function according to the difference feature probability expected to be searched, and converting the objective function into an objective function part component in a conjunctive normal form by using weight sequence coding; and forming an SAT model by the components, and solving the SAT model to find out the difference feature of the target password. The method can effectively reduce the number of Boolean variables introduced for describing the S-box difference probability information, improves the efficiency of searching the difference characteristics of the cryptographic algorithm, and can be used for the design and analysis of the cryptographic algorithm.

The application discloses a conjunctive normal form based semi-tensor product SAT solving method, which comprises the following steps: analyzing conjunctive normal form clauses; according to the analyzed conjunctive normal form clauses, combining each clause C x into a corresponding logical matrix representation M x , and obtaining M x ; combining the obtained M x into a group of matrix expressions through logical relationship; calculating the logical matrix representation according to the semi-tensor product SAT solving; and according to the satisfiable assignment of each C x , taking the intersection of each group of satisfiable assignments to obtain a group of satisfiable Boolean assignments satisfying all independent clauses C. The conjunctive normal form based semi-tensor product SAT solving method and device can reduce the calculation time, improve the calculation efficiency and improve the compactness of the satisfiable solution.

An automatic test pattern generation-based circuit verification method, comprises determining a to-be-detected first logic cone from a fan-out logic cone corresponding to the target line; determining, based on the first logic cone, a to-be-detected second logic cone from a fan-in logic cone corresponding to the target line; generating a first conjunctive normal form (CNF) based on the first logic cone and the second logic cone, and detecting the target line by using the first CNF to obtain a first detection result; and if the first logic cone is a partial region in the fan-out logic cone, and the first detection result meets a first specified condition corresponding to the first logic cone, determining a first verification result of the target line based on the first detection result.

According to the static program analysis abstract domain optimization method based on multi-objective optimization and parallel solution, a parallelization method is utilized, interval analysis of program variables is modeled into a multi-objective optimization problem by constructing a multi-objective optimization model, and objective and accurate solution is achieved by using a mathematical method. A bit vector constraint formula is converted into a conjunctive normal form CNF, so that an efficient SAT solver is supported, and the solving efficiency is improved; the CNF structure allows application clause simplification and conflict-driven clause learning, and the solution process can be accelerated. By using a parallel optimization method, the optimal value of each target under the constraint of the conjunctive normal form CNF is solved in a multi-thread parallel mode, the performance of a multi-core processor is fully utilized, and the solving time is shortened; a task scheduling algorithm is used for balancing thread loads, idle cores are avoided, and hardware performance is maximized. An optimal abstract domain analysis program is used, the precision of program analysis is improved, and misinformation and missing report of program analysis are reduced; and the program analysis time is shortened.

The embodiment of the invention provides a fault injection method and device, computer equipment, a computer readable storage medium and a computer program product, and relates to the technical field of computers. The fault injection method comprises the following steps: acquiring calling paths of a plurality of services based on a service request; obtaining a conjunctive normal form based on the calling path; the conjunctive normal form is used for describing failure conditions of service calling; obtaining at least one alternative hypothesis based on the conjunctive normal form; wherein one alternative hypothesis corresponds to at least one service; according to the path data of the calling path, obtaining the score of each service; determining a target alternative hypothesis according to the score of each service; and injecting the fault into the service of the target alternative hypothesis to carry out target testing. According to the technical scheme provided by the embodiment of the invention, the optimal selection of fault injection is realized, so that the fault hidden danger of the service can be effectively found.

The application discloses a simplification method of a conjunctive normal form probability constraint, and comprises the following steps: given a conjunctive normal form probability constraint, extracting all disjunction clauses in the conjunctive normal form expression in the SQL predicate of the probability constraint; setting the parameters in the relational expression in each disjunction clause, setting as many disjunction clauses as possible to be true, and reducing effective disjunction clauses; further, setting the parameters in the relational expression in the remaining disjunction clauses, and reducing effective relational expressions; finally, simplifying the original expression into a relational expression, a disjunction of multiple non-equivalent relational expressions, or a conjunction of multiple equivalent relational expressions; and finally obtaining the simplified probability constraint.

The application discloses a kind of planning methods for chip wiring layout fusion evolution and SAT solution, it is related to chip design technical field. Including: obtaining the conjunctive normal form of chip wiring layout problem, the coding rule of individual is defined;According to the search strategy and simplified evolution process of stage, search the optimal parameter combination about the value of evolution algorithm super parameter;Based on the optimal parameter combination and individual coding rule, initialize population and carry out iterative evolution;In the iteration process, based on conflict information and optimization target contribution, implement different cross mutation strategy, dynamically adjust the cross rate and mutation rate of each variable, while collecting key information, the individual that does not satisfy constraint is repaired directionally;Finally, according to the evaluation result screening individual, obtain global optimal solution set, realize the efficient solution to chip wiring layout problem, solve the problems such as poor timeliness, weak constraint satisfaction ability and low convergence quality of prior art.