Abstract: In simulating a physical circuit or system including analog and mixed signal digital-analog components, a computer models the physical circuit or system as a system of simultaneous equations. Conditional equations with associated conditions that can be true or false at different analog solution iterations result in a system of simultaneous equations that can change during the simulation. Rather than reformulating the system of simultaneous equations at each analog solution iteration, the system of simultaneous equations includes slots that are associated with conditional equations as the conditional equations become active. At a given point during the simulation, the conditions associated with the conditional equations are evaluated to determine which conditional equations are active. The values of the active conditional equations are placed in the slots in the system of simultaneous equations. System variables are associated with active conditional equations.

Abstract: In simulating a physical circuit or system including analog and mixed signal digital-analog components, a physical circuit or system includes components defined as instances of models. There can be multiple instances of any model in the physical circuit or system. For each model, a sub-system of simultaneous equations is determined. The variables in the sub-systems of simultaneous equations are classified as input, output, intermediate, or system variables. Equations are associated with each variable, and the sub-systems of simultaneous equations are reduced by eliminating all equations not associated with system variables. The system of simultaneous equations describing the physical circuit or system is assembled from the sub-systems of simultaneous equations. For each instance of a model, a copy of the sub-system of simultaneous equations for that model is added to the system of simultaneous equations.

Abstract: The Model Editor (106) makes simulation modeling easier and more intuitive by extracting essential information and presenting it to the user, and by providing tools to investigate simulation and model robustness, in an interactive, graphical environment. The Model Editor (106) includes a Newton step manager as an interactive, graphical tool. During simulation of a model, the Newton step manager captures matrix norms. Any indications of Newton limiting are also captured. The matrix norms are plotted as a function of iteration count, and the iterations at which Newton limiting were encountered are identified. Newton step manager can also be run automatically using a functional dependency analysis.

Abstract: An analysis mechanism is intended for use in a system performance simulator which includes a core simulator and which is intended for simulating the performance of a physical, real-world system, and which operates with a hardware description language. The hardware description language includes representations of physical, real-world devices in the form of a template set, wherein each template in the set includes an extraction mechanism for extracting indicators of system quality from the core simulator for each template, as the simulation progresses, or after simulation is complete. Additionally, a display interface is provided for displaying the system performance indicators of design quality to a designer, either during or after the simulation.

Abstract: The instant invention is a system performance simulator which includes a library of expression-literate model artifacts, each of which is at least partially representative, mathematically and operatively, of a model element which includes at least one virtual interface point suitable for operative association with another such point. Assembly means are operatively and disconnectably communicative with the library for accessing selected model artifacts and is capable of understanding the representative expression-literacies characterizing the artifacts, for establishing operative associations between interface points of the artifacts to establish an organized assembly of such artifacts. Means are also provided which are operatively communicative with the assembly means for conducting a performance simulation of such an assembly.

Abstract: A mixed-mode-simulator interface synchronizes, at non-regular intervals, a system simulator which includes an analog realm and an event-driven realm, wherein both simulators perform a simulation on a single, mixed-mode system. The interface uses an error-driven procedure to time advance the analog realm, and uses events in the analog realm to time advance the event-driven realm. Polynomial interpolation rollback is used to adjust analog realm time location.

Abstract: Simulation results enhancement software method and system are disclosed. A partial simulation results data base that is produced by an interactive simulator is software enhanced, using full elemental characterizations from the modeling subsystem thereof, to produce a simulation completion results data base. The simulation completion results data base is suitable for post-simulation processing to enable the viewing or plotting of any dependent variable, or transform thereof, available from the modeling subsystem. A simulation-produced interim results data base provides, in association with a software co-processor, the capability of interrupting the simulation upon the occurrence of a user-defined event. Use of the enhancement software is illustrated in the context of analog circuit simulation, whereby voltage, current and power waveforms are made available to the user without unduly burdening the computer system on which the simulation software is executed.