I have same question like VRP with different vehicle types using or-tools
two types of vehicles ：trucks and iveco
according to the traffic control policy of the local ，each types of vehicles can used routes was different :
for example：some road only can be used by trucks , others road only can be used by iveco, some accept both trucks and iveco...
despite this ，using only either trucks or iveco still can traverse all customers finally
now, already get the distance_matrix and time_matrix using only trucks ，and distance_matrix and time_matrix using only iveco
but I couldn't find the right function calculated the best routes , did anyone help?
you can register a transit function per vehicle type then pass an array of registered transit indices when creating a Dimension.
see this sample on gist: vrp_multiple_transit.py
Related
Is it possible to solve the Multiple Depot Vehicle Scheduling Problem (MDVSP) in OR-tools?
The problem is detailed in this paper, but here is a brief summary.
We are given a set of depots and the number of available vehicles at each. We are given a set of timetabled trips, and we know the origin, destination, start time, end time, and a set of depots that can serve a given trip. While connecting two trips, that is assigning a vehicle to serve for two trips sequentially, there may be an unoccupied travel, so called a dead-head trip. There are also dead-heads while going from a depot to the first trip and returning from the last trip to a depot. The objective is to minimize the sum of all dead-head trip costs while ensuring each trip is served by exactly one vehicle and the number of vehicles used does not exceed the availability. (Other trips/links, i.e., occupied trips, must in any case need to be served/traversed; so, there is no need to include them in the objective).
Seems you want to take into account the arc cost only if vehicle is empty. (note: fixed typo)
AFAIK, there is no easy way to do it using OR-Tools. In C++ you may use the DimensionDependentDimension and returning the arc cost if a capacity dimension is zero, and zero otherwise...
Also I'm curious why you would like to only count dead-trip e.g. if the overall vehicle route is several time longer with very few dead-trip instead of a shorter route with few dead-trip why would you want to incentive the first one ?
e.g. a route of 100km with 1km dead-trip is two time better than a 50km route with 2km dead-trip...
For multiple depots please take a look at
vrp_starts_ends.py
For TimeWindows: vrp_time_windows.py
Did you take a look at the documentation ?
e.g. https://developers.google.com/optimization/routing/cvrp
using routing.NextVar(A).SetValues([A, B]) you can force the chain A->B
ref: https://github.com/google/or-tools/blob/49b6301e1e1e231d654d79b6032e79809868a70e/ortools/constraint_solver/routing.h#L1364-L1366
note: Solver won't have the possibility to use A->C->B even if is shorter than A->B->C or C->A->B (supposing TW allow both of them...)
I am modeling a scenario where say my source is incoming orders, but order may have different characteristics, such as lines, units # of SKUs on the orders. Based on different characteristics, my service/delay time my differ. For example, my service time may be 1slines+ 5sunits+30s*SKUs. How can I set up my source and delay block to model this scenario?
Create an agent type for orders, add parameters for #SKUs etc.
In your delay block's duration field, use agent.numSKU to refer to a parameter numSKU in your agent type Order.
In your source, make sure it creates Order agents (not the default agents).
Lots of example models do this, please follow some of the basic tutorials and check the example models :)
i am currently testing outh the HERE CalculateMatrix API. My goal is to get all possible routes and find out the shortest one. Now im asking myself the following question:
Is it possible to define interim waypoints that an Route has to pass?
And is it possible that the order that these waypoints are passed is not defined?
So that i have for example the starting point: A, interim points: B and C an the destination: D,
and the Matrix should then calculate the following possible Routes:
A-B-C-D,
A-C-B-D
so im not using different destinations but different waypoints in between
As Raymond already mentioned in comments, it is not possible to use Calculate Matrix API for a use case of "sortable" way-points. The Fleet Telematics API does provide something close, although it would only provide the most optimal route and not all possible routes. In the API, some way-points can be marked as "sort" which means their order is not fixed and the API would then find the most optimal route.
From API reference (https://developer.here.com/documentation/fleet-telematics/dev_guide/topics/waypoint-sort-pickup-opening-times.html)
Sorting Waypoints (Travelling Salesman Problem) Routing can find the
optimal sequence order for the waypoints. Activate this feature by
following waypoint parameters:
&waypoint1=...;sort
All sections of waypoints flagged with "sort" can be rearranged by the
router for cost optimization. For example, in the waypoint list of
WP0, WP1;sort, WP2;sort, WP3;sort, WP4, WP5;sort, WP6;sort, WP7 the
router can change the sequence order among WP1, WP2 and WP3, and it
can change the sequence order among WP5 and WP6. If the last waypoint
is "sort"able then the route may end at any of the sortable waypoints.
Use this if the driver does his overnight stay simply at/after the
last waypoint he visited throughout the day.
&waypoint1=...;before:3,5
Enforces that the route meets waypoint 1 before the waypoints 3 and 5.
Use it in combination with either "sort" or "optional".
&waypoint1=...;implies:4,8
Enforces that if waypoint 1 is part of the route then also waypoints 4
and 8 must be part of the route. Use it in combination with "optional"
waypoints.
At my company we are currently using optaplanner to solve a vehicle routing problem with great results, we built a web app to manage vehicles, clientes, locations, depots and to show a graphic representation of the solution (including showing the locations in a map). We wrapped the solver in a spring java app with a rest interface to receive request and solve the problem. We are using Google maps to get distance-time data. Now we need to implement multirip....
To tackle the multitrip part I am following this approach:
1.- I added readyTime, endOfTrip and dueTime members to Vehicle class
2.- I created a rule to prevent arrivals at customers after vehicle->dueTime
3.- I modified the ArrivalTimeUpdateListener to consider the vehicle->readyTime when calculating the departureTime from a vehicle (using Math.max(depot->readyTime, vehicle->readyTime)
4.- At this point I started using the vehicle class as if it were a vehicle trip instead of a vehicle (I still don´t change the name but that is the idea )
5.- I created a member nextVehicle in vehicle to represent the next trip
6.- For testing purposes I manually link two vehicles (or vehicle trips) before sending it to solver->solve
7.- In the ArrivalTimeUpdatingVariableListener class I extended the method that updates the arrival times to consider updating the nextVehicle->readyTime and by consequence the arrival times of the customers that belong to the next trip (and so on when there are more than two trips)
I am sure this is not the most elegant solution, but I tried other approaches (using custom shadow variable on Vehicle for instance) but it couldn´t make it work.
The problem I am facing right now is that I don´t get to understand the state of the model when ArrivalTimeUpdatingVariableListener is called, maybe someone faced similar problem and can help me. What i found (after try and error) is:
the customer.getVehice() method not always returns a value (distinct from null value), it seems to get updated some time after the previousStandstill change triggers the listener "updateArrivalTime" method.
In construction fase when a customer get assign to a vehicle the customer.getVehice() method returns null (it came from "not assigned")
In construction fase when a customer "is freed" the customer.getVehice() method returns the "previous vehicle"
In local search fase when a customer get assign to a vehicle the customer.getVehice() method returns the "previous vehicle" (original vehicle)
In local search fase when a customer go back to the original vehicle the customer.getVehice() method returns the "previous assign vehicle"
Any thoughts on this? Am I making right assumptions? (because originally I considered customer.getVehicle() as the "actual" vehicle and the solutions were completely wrong...)
The order of triggering the previousStandstill change it´s kind of difficult to understand (for me). I mean when moving customers or swapping them between vehicles...any thoughts or hints on were to find info?
Can I access some variables from the "previous state of the model" when the solver makes a move?, because I am thinking I will need that if I continue with this approach (to update the vehicle->endOfTrip that is the nextVehicle->readyTime when the customer is the last one on the chain for instance)
and finally...am i doing something completely wrong conceptually ?
Any comments will be greatly appreciated (and sorry my grammar, I am native spanish speaker)
The chaotic triggering of shadow vars that you describe should not happen any more in optaplanner 6.3.0.Final or higher because it now gives the guarantee shown below.
But older versions (optaplanner 6.2 and earlier) suffer from that chaotic trigger behaviour (as fixed by PLANNER-252 - yes I know that issue number by heart - and yes, I am not the only one) could drive a developer (who's working on a complex model with multiple shadow variable(s)) insane and provide a one way ticket to the asylum.
Fortunately it has been fixed a few months ago, so upgrade to 6.3.0.Final or later and keep your sanity.
I am wondering if it is possible to do this as I am trying to build a traffic simulation model and may need to utilise this feature , should it exist, in my model.
There two, and only two, conditions under which a pair of turtles may be connected by more than one link:
If the links are directed, you can have two links, going in opposite directions.
If the links are different breeds.
You might consider alternatives like having a single link but adding a links-own variable to the links containing a weight, count, or other information.