1. A method comprising: representing a first graph in Euclidean space by a first model graph that includes all vertices of the first graph, all edges of the first graph, and at least one replicate vertex of the first graph, and is globally rigid and has a preselected maximum clique size; and computing a mapping between vertices of the first graph and vertices of a second graph by optimizing a mapping between vertices of the first model graph and vertices of the second graph respective to a cost function wherein the cost function includes at least a nodes term that assigns a cost to differences between vertices of the first model graph and mapped vertices of the second graph and an edges term that assigns a cost to differences between edges between vertex pairs of the first model graph and edges between mapped vertex pairs of the second graph; wherein the representing operation and the computing operation are performed by a digital processor.