ValueError: non-zero integer expected about pysat

[alexeyignatiev]

@omarshehab, this is to be expected. As the documentation says, variables are represented as natural numbers greater than 0. Just increment the values by 1 (i.e. a clause [1, 0] should become [2, 1]) and it will work. Also, note that edges (0, 1) and (1, 0) are represented by duplicate clauses and you may want to have a single copy of each clause.