Bulk Plan Multi-stop Shipment Conopt Merge Algorithm

The "Conopt merge" algorithm is selected by setting the multi-stop logic configuration parameter, MULTISTOP CONSOLIDATION ALGORITHM TYPE, to 'Conopt Merge'.

The Conopt Merge algorithm allows you to merge shipments if the total size (in terms of weight, volume and ERU) of two shipments exceeds the full-equipment capacity. This algorithm allows splitting of the shipments during the shipment consolidation steps in order to produce full-capacity shipments, thereby saving costs. Note that other existing multistop algorithms (e.g., Savings algorithm) primarily try to minimize the total distance of the consolidated shipments. However, in Conopt Merge, the main objective is to maximize the capacity utilization in consolidated shipments.

Though Conopt Merge algorithm has the capability to split and redistribute contents of input shipments, it takes care not to split the input shipments excessively. To be able to do that, OTM tries to keep items from an input shipment together as much as possible at the following levels (in order of increasing importance): stops, order, ship unit. It does not split ship units further by count. The Count Splittable check box on the order release ship unit triggers this, not the Bulk Splittable check box (also on the order release ship unit).

When Conopt Merge algorithm is used, we recommend setting the logic parameter MULTISTOP DISABLE SAME OD PAIRING to true.

If you want to use Conopt merge for multi-leg planning, you must use network routing.

Note: In Conopt Merge algorithm, the container optimization logic is used in OTM to repack tightly the ship units from all the direct shipments that are broken down at the beginning. It is important to note that, in this step, the container optimization logic does not check most multistop parameter settings, nor the rating and drive constraints. So the consolidated items may actually fail to combine in the end when all constraints are checked. This can impact the solution quality in the Conopt Merge algorithm when the planning scenario is very constrained (which could be due to location calendars, HOS rules etc.)

The following is NOT currently supported with the Conopt Merge algorithm:

3D load configuration
Carrier capacities
Equipment capacity overrides
Optimizing cost of the equipment set

Examples

Scenario 1 - One Source and Two Destinations

This scenario has two shipments with 60 ship units each from source A to destinations B and C which are close to each other in the same geographical region. If the equipment capacity is 100 ship units, these two shipments would not be combined as a multistop shipment.

However, you may want to create a full capacity multistop shipment (i.e. with 100 ship units) to locations B and C, and another shipment with 20 ship units to location C alone (maybe you can hold the second shipment for another day when it can be combined with other shipments).

On the image on the left there are three circles. The one labeled A has two arrows pointing to the B and C circles. The A-B route has 60 ship units as does the A-C route.

Scenario 2 - Single Source and Multiple Destinations

Consider 5 direct shipments from source A to destinations B, C, D, E, and F which are close to each other in the same geographical region. Suppose each of these shipments has 60 ship units (each weighing 1,000 LB) on an equipment with weight capacity 100,000 LB. Without this algorithm, OTM cannot split shipments inside multistop, so these shipments would not be consolidated into multistop shipments. However, this algorithm will allow splitting of these shipments, which will lead to three multistop shipments, thereby saving costs.

In the Current Scenario, A has lines to points B-F, each with 60 ship units departing from A. In the Desired Scenario, A has shipments of 100 going to B, D, and F. B and D both ship 40 to C. C sends 20 to E while F sends 40 to E. This leaves 60 at B-F.

Scenario 3 - Multiple Sources and Single Destination

Now, consider the reverse of the above; 5 direct shipments from source locations B, C, D, E, and F (which are again close to each other in the same geographical region) to one single destination location A. Each of these shipments has 60 ship units on an equipment of ship unit capacity 100.

Locations B-F all ship 60 ship units to location A.

Scenario 4 - One Source and Multiple Destinations, Different Quantities

Consider again a scenario with a single source and multiple destinations. Now suppose the direct shipments from A to B, D and F have 60 ship units each, and the direct shipments from A to C and E have 20 ship units each. Again assume that shipments use only an equipment with a ship unit capacity of 100. In this case, Conopt Merge as well as any existing multistop algorithm (e.g., Savings algorithm) will consolidate the 5 direct shipments to 3 shipments. However, note that Conopt Merge will create more tightly packed multistop shipments, which will come at the expense of additional travel distance for the shipments.

With other multistop algorithms, A sends shipments of 80 ship units to B and D, and 60 to F.. B then sends 20 to C while D sends 20 to E. With the Conopt Merge Algorithm, A sends shipments of 100 to B and D, with 20 going to F. B then sends 40 to C and C sends 20 to D. D sends 60 to E and E sends 40 to F. B-F ultimately receive the same number of ship units in both examples.

Multistop Logic Parameter Settings (for Conopt Merge Algorithm)

Note that the following multistop logic configuration parameters are not used by the Conopt Merge algorithm.

MULTISTOP COLGEN NUMBER OF ITERATIONS
MULTISTOP COLGEN SAVINGS ALGORITHM TYPE
MULTISTOP CONSOLIDATION ALLOW MULTITHREADING
MULTISTOP ENUMERATION MERGE MAX MERGES PER SHIP
MULTISTOP ENUMERATION MERGE MAX SHIPMENTS

All other multistop logic parameters are used in the Conopt Merge algorithm. In particular, Conopt Merge considers the following parameters at all stages:

MULTISTOP MAX DISTANCE BETWEEN DELIVERIES
MULTISTOP MAX DISTANCE BETWEEN PICKUPS
MULTISTOP MAX RADIUS FOR DELIVERIES
MULTISTOP MAX RADIUS FOR PICKUPS
MULTISTOP MAX TIME BETWEEN DELIVERIES
MULTISTOP MAX TIME BETWEEN PICKUPS
MAXIMUM PICKUP STOPS ALLOWED
MAXIMUM DELIVERY STOPS ALLOWED
MAXIMUM STOPS ALLOWED

We recommend that you use your settings for only the above parameters and use default settings for the remaining logic parameters.

When Conopt Merge algorithm is used, we recommend setting the logic parameter MULTISTOP DISABLE SAME OD PAIRING to true.

Container Optimization Settings

The user settings in the container optimization logic configuration will not be used by this multistop split logic while repacking contents of the shipments tightly. OTM will use some default container optimization parameter settings for that purpose, but you have a choice on the settings for the following logic parameters (in the Multistop logic configuration parameters under 'MULTISTOP PACKING').

Note: Enable the log ID 'OptMipData' to export a CSV file of column generation information (like columns, dual, variable names and their OTM object references, assignment or shipment sequence) when it is used. This log can be used to analyse the solution obtained from the column generation if MULTISTOP PACKING ALGORITHM is Column Generation.

Logs and Diagnostics

The following System Log IDs, "Multistop" and "MultistopDetails" help to analyze program flow and detect failures that occur inside the code for this algorithm.