Initialise weighted degree by setting the initial value for each constraint's failure count to Factor. The weighted degree for a variable is the sum of all its constraints failure count, i.e. Factor*(degree for variable).By default, the initial failure count for each constraint is set to 1.0, so the initial weighted degree for a domain variable is its degree (number of associated constraints).
As with failure count for a constraint is automatically set, init_weighted_degree/1 is only needed if the user want to erase the accumulated failure counts and reset the weighted degree for variables, and/or if a different value for Factor is wanted.
Changing Factor changes the relative importance of subsequent failures, The smaller the Factor, the more important each failure will be in the subsequent changes in the weighted degree. Note that unless Factor is set to 0, the initial relative ordering of weighted degree will not change (subject to floating point precision considerations).