  The initial phase of the inspiral process of a binary system producing
gravitational waves can be described by perturbation theory. At the third
post-Minkowskian order a two-loop double box graph, known as H-graph
contributes. We consider the case where the two objects making up the binary
system have equal masses. We express all master integrals related to the
equal-mass H-graph up to weight four in terms of multiple polylogarithms. We
provide a numerical program which evaluates all master integrals up to weight
four in the physical regions with arbitrary precision.
