I am trying to study the social network of the center where I am working. I have done a compilation of relation between personal from programed meeting, formal working team, etc. to analyze structural relevant positions. I recapitulated all these information in a matrix of incidence: a square symmetric matrix which entries are related with the time two persons stay together. This matrix is in Excel.
I am looking for free software which draws a graph from the incidence matrix via importation of Excel file.
Thank you in advance