A circuit is simulated by using system or network tearing to obtain a real solution. The circuit may be an entire integrated circuit, portion of an integrated circuit, or a circuit block. A circuit simulation technique of the invention generates a system graph, finds a tree, and partitions the tree into two or more subtrees. The technique identifies global links and local links in the graph. Each subtree may be solved individually using distributed, parallel computing. Using the results for the subtrees, the technique obtains a real solution, branch voltages and currents, for the circuit.