David Nettleton

The present invention proposes a new approximate sub-graph matching method with the advantage of a relatively simple to implement matching method, requiring a worst case runtime computational cost of O(N2). The present invention refers to a similarity metric which approximates a modified isomorphism matcher for local neighbourhood sub-graphs, the matcher consisting in a distance metric with weighted characteristics in terms of sub-graph statistics and statistics of neighbour node degrees. The weights of the metric are calibrated using a simulated annealing process which uses as a fitness function a modified isomorphism matcher which takes into account how well the match maintains the neighbouring node degree distributions. The learned weights provide additional information useful to interpret the relative importance of each characteristic.