Roth-Karp decomposition is a classical functional decomposition technique;
because it can decompose a node into a set of nodes with fewer numbers of f
anins, it is one of the most popular techniques for look-up table (LUT)-bas
ed field-programmable gate array technology mapping. The compatible-class e
ncoding problem in Roth-Karp decompositions is discussed in the paper. It i
s shown how to formulate this problem as a symbolic-output encoding problem
to exploit the feature of the two-output LUT architecture specifically. Ba
sed on this formulation an encoding algorithm is developed to minimise the
number of LUTs used to implement the logic circuit. Experimental results sh
ow that the encoding algorithm can produce promising results to implement b
oolean networks in the logic synthesis environment for the two-output LUT a
rchitecture.