In message "Blackburn Simon" writes: > Hi, > I am calculating wannier functions for a highly correlated material, but I got negative spreads for some functions : > … > I changed the functions and also I exclude low energy bands, but I still got negative spreads, however they were not necessarily for the same functions. > > I would like to know how come some spreads are negative and how to solve this problem. Simon, Try setting guiding_centres=T in the *.win file and see if that helps (ie makes the negative spreads go away) This is generally a good thing to try when the results appear un-physical. The guiding centres option is related to branch cuts in the log definition of the spread (see the original Marzari-Vanderbilt paper). If that isn't the cause of your problem, then I suspect the next step is to put the mmn,amn and eig files on a webserver - so that we can look at the problem in more detail. Unless anyone else has seen, and cured, this type of problem before? Yours Jonathan