Worst Case Performance of an Approximation Algorithm for Asymmetric TSP

In 1982 Frieze, Galbiati and Maffioli (Networks 12:23-39) published their famous algorithm for approximating the TSP tour in an asymmetric graph with triangle inequality. They show that the algorithm approximates the TSP tour within a factor of log2 n. We construct a family of graphs for which the algorithm (with some implementation details specified by us) gives an approximation which is log2 n / (2 + 2e) times the optimum solution. This shows that the analysis by Frieze et al. is tight up to a constant factor and can hopefully give deeper understanding of the problem and new ideas in developing an improved approximation algorithm.