  The surface code is designed to suppress errors in quantum computing hardware
and currently offers the most believable pathway to large-scale quantum
computation. The surface code requires a 2-D array of nearest-neighbor coupled
qubits that are capable of implementing a universal set of gates with error
rates below approximately 1%, requirements compatible with experimental
reality. Consequently, a number of authors are attempting to squeeze additional
performance out of the surface code. We describe an optimal complexity error
suppression algorithm, parallelizable to O(1) given constant computing
resources per unit area, and provide evidence that this algorithm exploits
correlations in the error models of each gate in an asymptotically optimal
manner.
