Applying the displacement resolver has no effect when both variables are non-singleton.
Suppose there are two variables v0∈{a,b,c} and v1∈{a,b}, enforcing the constraint v0≠v1 has no effect on the domains of the v0 and v1 variables hence, once applied the resolver, the flaw will reemerge at the next iteration.
In case of non-singleton variables, the displacement resolver could be replaced with n placement resolvers. In the above case, for example, the displacement resolver would be replaced with those placement resolvers which would assign different values to the v0 and v1 variables, i.e. <a,b>, <b,a>, <c,a> and <c,b>.
Placement resolvers are heavy committing resolvers and should hence be despised, compared to other resolvers..
Applying the displacement resolver has no effect when both variables are non-singleton.
Suppose there are two variables
v0∈{a,b,c}andv1∈{a,b}, enforcing the constraintv0≠v1has no effect on the domains of thev0andv1variables hence, once applied the resolver, the flaw will reemerge at the next iteration.In case of non-singleton variables, the displacement resolver could be replaced with
nplacement resolvers. In the above case, for example, the displacement resolver would be replaced with those placement resolvers which would assign different values to thev0andv1variables, i.e.<a,b>,<b,a>,<c,a>and<c,b>.Placement resolvers are heavy committing resolvers and should hence be despised, compared to other resolvers..