5. The method of claim 4, wherein selecting at least one variable of the selected constraint and selecting a new value for each selected variable comprise: altering, for one or more variables of the selected constraint, the current values of the variables to generate an altered current assignment; computing a score for the altered current assignment; ranking the scores for one or more altered current assignments; and selecting the variable and the new value for each selected variable according to the ranking.
6. The method of claim 5, wherein altering the current value of a variable further comprises changing its value to another value from the domain of the variable to improve the score of the current assignment.