  Numerical reconstruction techniques are widely employed in the calculation of
multi-loop scattering amplitudes. In recent years, it has been observed that
the rational functions in multi-loop calculations greatly simplify under
partial fractioning. In this article, we present a technique to reconstruct
rational functions directly in partial-fractioned form, by evaluating the
functions at special integer points chosen for their properties under a p-adic
metric. As an application, we apply this technique to reconstruct the largest
rational function in the integration-by-parts reduction of one of the rank-5
integrals appearing in 2-loop 5-point full-colour massless QCD amplitude
calculations. The number of required numerical probes (per prime field) is
found to be around 25 times smaller than in conventional techniques, and the
obtained result is 130 times smaller. The reconstructed result displays signs
of additional structure that could be used to further reduce its size and the
number of required probes.
