Computing the Diameters of Abelian Cayley Digraphs with Degree 2

Suppose that x
₁
, y
₁
, x
₂
and y
₂
are four integers. For a given Cayley digraph Omega=Cay(G, {a, b}), where G=Z
²
/K, a=(1, 0)+K, b=(0, 1)+K, K=, alpha=(x
₁
, y
₂
), beta=(x
₂
, y
₂
), an algorithm is given to compute the four parameters l, h, m, n of its L-shape tile. Thus the diameter of this Cayley digraph can be calculated by d(Omega)=max{l+h-m-2, l+h-n-2}.