Back to random topology

In 2004 I de ned and put on line a simple PSO with random topology. More precisely the communication topology (infonetwork) was randomly modi ed after an iteration if there had been no improvement of the global best. However, although the C code is freely available from now several years, and although it has been published in 2005 in my book [2] with some explanations (and in 2006 in the English translation [3]), it appears that some people not understood well the method that is used. Hence this short paper, in which I simply explain how I found it, starting from my rst bad idea to a more e ective one.