  We present a self-contained description of the wave-function matching (WFM)
method to calculate electronic quantum transport properties of nanostructures
using the Landauer-B\"uttiker approach. The method is based on a partition of
the system between a central region ("conductor") containing $N_S$ sites and an
asymptotic region ("leads") characterized by $N_P$ open channels. The two
subsystems are linearly coupled and solved simultaneously using an efficient
sparse linear solver. Invoking the sparsity of the Hamiltonian matrix
representation of the central region, we show that the number of operations
required by the WFM method in conductance calculations scales with $\sim
N_S\times N_P$ for large $N_S$.
