Cadence Design Systems, Inc.

Synopsys, Inc.

Gemini Design Technology, Inc.

Baolin Yang

Bruce W McGaughy

Joel Reuben Phillips

Jun Kong

Peter Frey

Wai Chung William Au

Qian Cai

A method of determining values for a circuit over a cycle includes: specifying first-cycle values for the circuit in a first cycle, the first-cycle values including voltage or current values for the circuit and providing reference cyclic values for characterizing a cyclic behavior of the circuit in the first cycle with a reference cyclic dimension; determining, from the first-cycle values, path-following values for the circuit in a second cycle, wherein the path-following values include transient values for characterizing a transient behavior of the circuit and cyclic-correction values for characterizing the cyclic behavior of the circuit relative to the reference cyclic values from the first cycle, wherein a cyclic-correction dimension of the cyclic-correction values is less than the reference cyclic dimension; and saving at least some values based on the path-following values in the second cycle.

Adaptive solver for cyclic behavior of a circuit

A computer-implemented method for solving parallel equations in a circuit simulation is described. The method includes partitioning a circuit Jacobian matrix into loosely coupled partitions, reordering the voltage vector and the matrix according to the partitions, and splitting the Jacobian matrix into two matrices M and N, where M is a matrix suitable for parallel processing and N is a coupling matrix. M and N are then preconditioned to form MJx=(I+MN)x=Mr and the Jacobian matrix J is solved using an iterative solving method.

Parallel multi-rate circuit simulation

In one embodiment, a method for ranking webpages is provided. The method includes generating a web circuit model having a node representing each webpage. The model is simulated to identify the potential at each node. The webpages can then be ranked according to the potentials of the nodes to which the webpages correspond.

Method for ranking webpages via circuit simulation

A method, computer program product, and apparatus for simulating circuits. The method comprises modeling a circuit with an appropriate system of equations, partitioning a time interval on which the system of equations is defined, producing an interpolating polynomial on the time interval, and applying a two tiered iterative approach to solve the system of equations. The approach begins by decomposing a candidate solution vector into its time domain and frequency domain components. The Fourier transform is applied to the frequency domain components and time domain methods are applied to both the time domain components and the Fourier transformed frequency domain components to generate the solution to the original system of equations. Newton's method can be used in combination with a Krylov iterative subspace solver to perform the two-tiered iteration. The computer program product and the apparatus implement the method of simulating circuits.

Simulation of electrical circuits

Method and system for determining electrical isomorphism between two electrical networks are disclosed. In one embodiment, the method includes representing the circuit as a hierarchically-arranged set of branches. The hierarchically-arranged set of branches including a first branch that includes a first electrical network and a second branch that includes a second electrical network, where the first and second branches are interconnected in the graph through a third branch at a higher hierarchical level in the graph than the first and second branches. Next, the method determines whether the first and second electrical networks are electrically isomorphic networks. If the first and second electrical networks are determined to be electrically isomorphic networks, the first and second electrical networks are represented with a single electrically isomorphic network. The method further includes simulating the first and second electrical networks using the single electrically isomorphic network.

Electrical isomorphism

A system for supporting multi-rate simulation of a circuit having a hierarchical data structure includes a simulator module having one or more computer programs for 1) partitioning the circuit into a plurality of group circuits, each group circuit includes one or more leaf circuits, where each leaf circuit produces a predictable set of output signals with a given set of input signals, 2) storing the group circuits in a scheduled event queue in accordance with priority in time which the group circuits need to be simulated, 3) retrieving from the scheduled event queue a set of group circuits for simulation within a predetermined time period, 4) distributing the set of group circuits into a set of predefined event lists, where each of the predefined event list stores one or more group circuits of a corresponding event type, and 5) simulating the one or more group circuits in each of the predefined event list in accordance with a rate of change of signal conditions of each individual group circuit. Hence, the system provides an efficient way to support multi-rate simulation by dynamically scheduling and synchronizing multiple group simulation event types and by communicating corresponding isomorphic activities through an efficient port connectivity interface.

System and method for supporting multi-rate simulation of a circuit having hierarchical data structure

An system and method are disclosed for efficiently approximating analytical circuit device models. A preferred embodiment includes a method for obtaining smooth and accurate approximations of analytical device models, comprising the steps of identifying a first set of measurement units; locating two or more sets of units that neighbor one or more of said measurement units; for each set of the two or more sets of neighbor units, obtaining the union of one or more of said sets of neighbor units and the first set of measurement units; calculating the smoothness of the analytical device model within one or more of said unions; and selecting at least one of said unions within which the analytical device model is the smoothest as the new set of measurement units.

System and method for high-order accurate device model approximation

A method and apparatus are provided for solving a set of differential-algebraic equation arising in a circuit simulation is provided. A collocation method is applied to each differential-algebraic equation to discretize the set of differential-algebraic equations. A solution to the set of differential-algebraic equations based on the discretized differential-algebraic equation is then formed.

Method and device for multi-interval collocation for efficient high accuracy circuit simulation

A system for adaptive partitioning of circuit components during simulating of a circuit having a hierarchical data structure includes a simulator module having one or more computer programs for 1) selecting a group of leaf circuits from the first branch and the second branch for simulation, where each leaf circuit is represented by a matrix comprising a set of equations, 2) determining a strength of coupling between two or more leaf circuits of the group in accordance with a set of predetermined electrical coupling criteria, 3) if two or more leaf circuits are deemed be strongly coupled, combining the corresponding matrix of each strongly coupled leaf circuit into a combined matrix, and 4) performing computation for the two or more strongly coupled leaf circuits in accordance with the combined matrix. The system adaptively adjusts the group circuit matrix for computing a group of circuits according to the strength of coupling between the circuits. Hence, it achieves higher simulation performance by reducing either the size of the solver matrix when the circuits are loosely connected to each other, or by reducing the number of computational repetitions due to the communication of changes of signal conditions between circuits by combining the individual circuit matrices when such circuits are closely coupled to each other.

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Fremont, CA, United States of America

Baolin Yang