  Diophantine equations can often be reduced to various types of classical Thue
equations. These equations usually have only very small solutions, on the other
hand to compute all solutions (i.e. to prove the non-existence of large
solutions) is a time consuming procedure. Therefore it is very practical to
have a fast algorithm to calculate the "small" solutions, especially if "small"
means less than e.g. $10^{100}$. Such an algorithm was constructed by A.Peth\H
o in 1987 based on continued fractions.
  In the present paper we construct a similar type of fast algorithm to
calculate "small" solutions of {\it relative} Thue equations. Our method is
based on the LLL reduction algorithm. We illustrate the method with explicit
examples. The algorithm has several applications.
