Systems and methods for efficiently simulating analog behavior of designs having hierarchical structure

A system for simulating a circuit, comprising:

• at least one processing unit for executing computer programs;
• a user interface for performing at least one of the functions selected from the group consisting of entering a netlist representation of the circuit, viewing representations of the circuit on a display, and observing simulation results of the circuit;
• a memory for storing simulation databases and simulation results;
• means for representing the circuit as a hierarchically arranged set of branches, including a root branch and a plurality of other branches logically organized in a graph;
• the hierarchically arranged set of branches including a first branch that includes one or more subcircuits and a second branch that includes one or more subcircuits;
• wherein the first branch and second branch are interconnected in the graph through a third branch at a higher hierarchical level in the graph than the first and second branches;
• wherein a subcircuit at a higher hierarchical level comprises one or more subcircuits in a lower hierarchical level;
• means for arranging the subcircuits from the hierarchically arranged set of branches into one or more groups;
• means for determining a data structure for each subcircuit in a group, wherein the data structure supports a combination of selectively flattened and selectively expanded group of subcircuits;
• means for selecting a subcircuit as a simulation leader in each group and identifying remaining subcircuits as followers in the group, wherein each simulation leader has states substantially equivalent to the followers;
• means for simulating the respective simulation leader of each group using a selectable simulation driver;
• and
• means for replicating simulation results of the respective simulation leader of each group to its followers.

A computer program product, comprising a medium storing computer programs for execution by one or more computer systems, the computer program product comprising:

• a simulator module for simulating a circuit, wherein the simulator module is used in conjunction with at least a processing unit, a user interface and a memory, and the simulator module includes one or more computer programs containing instructions for:
• representing the circuit as a hierarchically arranged set of branches, including a root branch and a plurality of other branches logically organized in a graph;
• the hierarchically arranged set of branches including a first branch that includes one or more subcircuits and a second branch that includes one or more subcircuits;
• wherein the first branch and second branch are interconnected in the graph through a third branch at a higher hierarchical level in the graph than the first and second branches;
• wherein a subcircuit at a higher hierarchical level comprises one or more subcircuits in a lower hierarchical level;
• arranging the subcircuits from the hierarchically arranged set of branches into one or more groups;
• determining a data structure for each subcircuit in a group, wherein the data structure supports a combination of selectively flattened and selectively expanded group of subcircuits;
• selecting a subcircuit as a simulation leader in each group and identifying remaining subcircuits as followers in the group, wherein each simulation leader has states substantially equivalent to the followers;
• simulating the respective simulation leader of each group using a selectable simulation driver;
• storing simulation results of the respective simulation leader of each group;
• and replicating the simulation results of the respective simulation leader of each group to its followers.