Hungarian Assignment Algorithm Implementation
The article you linked assumes that the reader knows how to apply the Hungarian algorithm on a similarity matrix because they have note in the introduction to Section 3 that Zager et. al. used the Hungarian algorithm for this purpose in the paper here.

Furthermore, there is no requirement in the Hungarian algorithm that necessitates integral entries; neither the Wikipedia article and this slide deck mention any requirement for the entries to be integers.  Authors may use integer values for examples because they're easy to work with, but that does not mean the algorithm requires them.