Fujitsu Corporation

Debashis Sahoo

Jawahar Jain

Subramanian K Iyer

Amit Narayan

Christian Stangier

Yoshihisa Kojima

Koichiro Takayama

Takaya Ogawa

A method for evaluating an erroneous state associated with a target circuit is provided that includes receiving information associated with a target circuit, the information identifying a property within the target circuit to be verified. One or more partitioned ordered binary decision diagram (POBDD) operations are executed using the information in order to identify an erroneous state associated with a sub-space within the target circuit. A path associated with the erroneous state is identified. The path reflects a correlation between an initial state associated with the erroneous state and a point where the erroneous state was encountered.

System and method for evaluating an erroneous state associated with a target circuit

In one embodiment, a method for multithreaded reachability analysis includes partitioning a state space of a circuit under analysis into a plurality of partitions and assigning each partition to a thread to carry out a reachability analysis on the partition assigned to the thread. The threads carry out the reachability analyses of the partitions in parallel with each other. The method also includes using one or more of an early communication algorithm and a partial communication algorithm to communicate states from one or more first ones of the partitions to one or more second ones of the partitions to facilitate the reachability analysis of the second ones of the partitions.

Multithreaded reachability

In one embodiment, a method for verifying one or more particular properties of a circuit using a learning strategy to determine suitable values of particular verification parameters includes classifying each of multiple properties of a circuit according to circuit size and selecting a candidate property from the properties. The candidate property set includes one or more particular properties from each property class. The method also includes attempting to verify one or more particular properties of the circuit using the candidate property set and particular values of particular verification parameters. The method also includes determining suitable values of the particular verification parameters according the attempted verification of the particular properties of the circuit using the candidate property set and the particular values of the particular verification parameters.

Circuit verification

In one embodiment, a method for circuit verification using multiple engines includes running multiple traces on a circuit using multiple reachability algorithms, selecting an effective reachability algorithm for the circuit from among the multiple reachability algorithms according to a comparison of results of the multiple traces with each other, generating a set of initial states for the selected effective reachability algorithm using states reached in the plurality of traces, and executing the selected effective reachability algorithm using the generated set of initial states to verify the circuit.

Circuit verification using multiple engines

In one embodiment, a method for determining one or more reachable states in a circuit using distributed computing and one or more partitioned data structures includes, at a first one of multiple computing systems, receiving a first partition of a circuit. The first partition corresponds to a first binary decision diagram (BDD) having a first density. The method includes performing a first reachability analysis on the first partition using the first BDD until a fixed point in the first partition has been reached and, if, during the first reachability analysis, the size of the first BDD exceeds a threshold, discarding the first BDD. The method includes communicating with at least one second one of the multiple computing systems. The second one of the multiple computing systems has received a second partition of the circuit. The second one of the multiple computing systems has performed a second reachability analysis on the second BDD without discarding the second BDD.

Determining one or more reachable states in a circuit using distributed computing and one or more partitioned data structures

A method for verifying a property associated with a target circuit is provided that includes receiving information associated with a target circuit, the information identifying a property within the target circuit to be verified. One or more operations may be executed in order to generate a set of transition relations for performing a reachability analysis associated with the target circuit. An image associated with the target circuit may be partitioned into a plurality of leaves that may each represent a subset of a final image to be generated by a partitioned ordered binary decision diagram (POBDD) data structure. An analysis may be computed of one or more of the leaves using a selected one or both of conjunction and quantification operations separately.

System and method for executing image computation associated with a target circuit

In one embodiment, a system for verifying a circuit using a scheduling technique includes one or more partitioned ordered binary decision diagram (POBDD) modules that collectively generate one or more POBDDs. Each POBDD corresponds to one or more partitions of a state space of the circuit and includes a number of states and a number of nodes in the partition. The system also includes one or more cost metrics modules that collectively determine a processing cost of each of the partitions of each of the POBDDs. The system also includes one or more scheduling modules that collectively schedule processing of the partitions of the POBDDs for semiformal verification of a circuit. The schedule is based, at least in part, on the determined processing costs of the partitions of the POBDDs.

A method for verifying a property associated with a target circuit is provided that includes receiving information associated with a target circuit, the information identifying a property within the target circuit to be verified. One or more partitioned ordered binary decision diagram (POBDD) operations are then executed using the information in order to generate a first set of states at a first depth associated with a sub-space within the target circuit. Bounded model checking may be executed using the first set of states in order to generate a second set of states at a second depth associated with the sub-space within the target circuit. The first set of states may be used as a basis for the second set of states such that the second depth is greater than the first depth.

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Stanford, CA, United States of America

Debashis Sahoo