/**
* Create a search strategy which selects the variables to branch on with <code>VAR_SELECTOR
* </code>, then select the value closest to the middle value of its domain, and split its domain
* into two intervals (binary decisions will be used). If <code>LOWERFIRST</code> is set to true,
* the domain is restricted to the left interval first. If <code>LOWERFIRST</code> is set to
* false, the domain is restricted to the right interval first.
*
* @param VAR_SELECTOR a variable selector
* @param LOWERFIRST set to true to select first the left interval, false otherwise
* @param VARS variables to branch on
* @return a dichotomic strategy for IntVar
*/
public static IntStrategy dichotomic(
VariableSelector<IntVar> VAR_SELECTOR, boolean LOWERFIRST, IntVar... VARS) {
if (LOWERFIRST) {
return custom(
VAR_SELECTOR, ISF.mid_value_selector(LOWERFIRST), DecisionOperator.int_split, VARS);
} else {
return custom(
VAR_SELECTOR,
ISF.mid_value_selector(LOWERFIRST),
DecisionOperator.int_reverse_split,
VARS);
}
}
/**
* Splits the domain of the first non-instantiated variable in the middle and branch first on the
* left interval
*
* @param VARS list of variables
* @return int strategy based on domain splits
*/
public static IntStrategy lexico_Split(IntVar... VARS) {
return dichotomic(ISF.lexico_var_selector(), true, VARS);
}