  A non-iterative method is presented for the factorization step of sector
decomposition method, which separates infrared divergent part from loop
integration. This method is based on a classification of asymptotic behavior of
polynomials. The problem is converted to ones for convex body in Euclidean
space. They are solved with algorithms developed in computational geometry. A
test implementation shows that this method produces less number of decomposed
sectors than usual iterative sector decompositions.
