  This study is targeted to the NLO corrections of multileg processes, very
important for the LHC. Starting from the construction of Feynman diagrams, the
analytical reduction of general one-loop integrals to scalar master ones, the
calculation of color structures, manipulation of spinor lines and other
amplitude constituents and finally phase space point selection are obtained by
use of a program producing Fortran code for numerical calculation of one-loop
corrections for processes like gg -> t bar_t+gg.
