  Evaluation of a wide variety of Feynman diagrams with multi-loop integrals
and physical parameters and its comparison with high energy experiments are
expected to investigate new physics beyond the Standard Model. We have been
developing a direct computation method of multi-loop integrals of Feynman
diagrams. One of features of our method is that we adopt the double exponential
rule for numerical integrations which enables us to evaluate loop integrals
with boundary singularities. Another feature is that in order to accelerate the
numerical integrations with multi-precision calculations, we develop an
accelerator system with Field Programmable Gate Array boards on which
processing elements with dedicated logic for quadruple/hexuple/octuple
precision arithmetic operations are implemented. In addition, we also develop a
programming interface designed for easy use of the system. The development is
continued for practical use of the system. We present the current development
of our system, and the numerical results of higher-loop diagrams performed
using our system.
