Break, early vs. late

jie31best · December 12, 2017, 4:17am

Hi all,

When I check the service insertion calculator, the shipment insertion calculator, and the break insertion calculator, I notice that they all favor an early insertion of the job/activity over a late one if both lead to the same insertion cost.

I am not sure about service and shipment, but I think for break a late insertion should be favored over an early one. What do you think?

The change would be simple - just change the < to <= in this line:

github.com

graphhopper/jsprit/blob/master/jsprit-core/src/main/java/com/graphhopper/jsprit/core/algorithm/recreate/BreakInsertionCalculator.java#L157


List<Location> locations = Arrays.asList(prevAct.getLocation(), nextAct.getLocation());
for (Location location : locations) {
    breakAct2Insert.setLocation(location);
    breakAct2Insert.setTheoreticalEarliestOperationStartTime(breakToInsert.getTimeWindow().getStart());
    breakAct2Insert.setTheoreticalLatestOperationStartTime(breakToInsert.getTimeWindow().getEnd());
    ConstraintsStatus status = hardActivityLevelConstraint.fulfilled(insertionContext, prevAct, breakAct2Insert, nextAct, prevActStartTime);
    if (status.equals(ConstraintsStatus.FULFILLED)) {
        //from job2insert induced costs at activity level
        double additionalICostsAtActLevel = softActivityConstraint.getCosts(insertionContext, prevAct, breakAct2Insert, nextAct, prevActStartTime);
        double additionalTransportationCosts = additionalTransportCostsCalculator.getCosts(insertionContext, prevAct, nextAct, breakAct2Insert, prevActStartTime);
        if (additionalICostsAtRouteLevel + additionalICostsAtActLevel + additionalTransportationCosts < bestCost) {
            bestCost = additionalICostsAtRouteLevel + additionalICostsAtActLevel + additionalTransportationCosts;
            insertionIndex = actIndex;
            bestLocation = location;
        }
        breakThis = false;
    } else if (status.equals(ConstraintsStatus.NOT_FULFILLED)) {
        breakThis = false;
    }
}
double nextActArrTime = prevActStartTime + transportCosts.getTransportTime(prevAct.getLocation(), nextAct.getLocation(), prevActStartTime, newDriver, newVehicle);

Best regards,
He

jie31best · December 12, 2017, 8:18am

Interesting, the aforementioned change seems to resolve this:

ifley · July 22, 2018, 11:46am

Are there any news about bug with Break. I also encountering to this issue