<< MB.m

<< AMBRE.m

Fullintegral[{1}, {PR[p1 + k1, m, n1]*PR[p1 + p5 + k1, 0, n2]*
            PR[p1 + p5 + p4 + k1, m, n3] PR[p1 + p5 + p4 + p3 + k1, m, 
              n4] PR[k1, 0, n5]}, {k1}];

invariants = {p1^2 -> m^2, p2^2 -> m^2, p3^2 -> 0, 
          p4^2 -> m^2, p5^2 -> m^2, 
          p1*p2 -> 1/2 (tp - 2  m^2), 
          p1*p3 -> 1/2 (t - tp - v1), 
          p1*p4 -> m^2 - 1/2 (s + t - v1), 
          p1*p5 -> 1/2 (s - 2  m^2), p2 p3 -> 1/2 v1, 
          p2 p4 -> 1/2 (s - 2  m^2 - v1 - v2), 
          p2 p5 -> m^2 - 1/2 (s + tp - v2), 
          p3 p4 -> 1/2  v2, p3 p5 -> 1/2 (tp - t - v2), 
          p4 p5 -> 1/2 (t - 2 m^2)};

IntPart[1]

repr = SubLoop[integral];

fin = BarnesLemma[repr, 1]

fin = % /. {n1 -> 1, n2 -> 1, n3 -> 1, n4 -> 1, 
          n5 -> 1}

rules = MBoptimizedRules[fin, eps -> 0, {}, {eps}]

integrals = 
        MBcontinue[fin, eps -> 0, rules, 
          Verbose -> False];

ser = 
        MBexpand[integrals, Exp[eps EulerGamma], {eps, 0, 0}];

AbsoluteTiming[
      MBintegrate[
        ser, {s -> -2, t -> -3, v2 -> -4, 
          tp -> -5, v1 -> -6, m -> 1}, 
        Verbose -> False]]