Numerical implementation of the loop–tree duality method Sebastian Buchta, Grigorios Chachamis, Petros Draggiotis and Germán Rodrigo Eur. Phys. J. C, 77 5 (2017) 274 Published online: 02 May 2017 DOI: 10.1140/epjc/s10052-017-4833-6