1. A method for simulating an electric circuit that is represented as one or more partitions, each partition comprising a plurality of constituents representing portions of the circuit, wherein at least one of the constituents is a variable constituent for which the corresponding portion of the electronic circuit includes non-linear behavior, the method comprising: determining a first matrix for the variable constituent, wherein the first matrix describes a system of equations that represents a behavior of the variable constituent; determining a second matrix for the partition, wherein the second matrix permits calculation of short circuit currents on each terminal of each constituent from open circuit voltages on the terminals according to a node tearing analysis method; and simulating a timestep of the simulation, the simulating comprising: iteratively solving a state of the partition using successive guesses of the state of the variable constituent, each iteration comprising solving the variable constituent independently to generate the open circuit voltages, applying the second matrix to determine the short circuit currents, and resolving the variable constituent with the short circuit currents applied and internal forcing functions of variable partition disabled; converging to a solution during the iteratively solving; and solving the state of the partition for the timestep responsive to the converging.