1. One or more computer-readable media storing computer-executable instructions for causing a computer to perform a method, the method comprising: receiving circuit design information, the circuit design information indicating at least a geometric layout of conductors in a circuit design and a desired frequency of operation for the circuit design; defining conduction modes representing distribution functions for currents in the conductors at the desired frequency of operation; generating a conduction mode matrix, the conduction mode matrix including matrix elements based on the defined conduction modes; computing values for one or more matrix elements by decomposing integrands for calculating the matrix elements into simplified terms that are less computationally intensive than the integrands and computing values of the simplified terms; and storing the values for the one or more matrix elements.