A method performed by at least one processor includes: accessing a layout of an integrated circuit (IC), the layout comprising a resistor-capacitor (RC) netlist comprising a plurality of circuit nodes; identifying an RC network in the RC netlist; determining a characterization matrix corresponding to the RC network; updating the RC netlist by replacing the RC network with the characterization matrix; and calculating voltages and currents of the plurality of circuit nodes based on the updated RC netlist.