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Single Chain

Evaluates two-object chains: one object leaves the hot container for another container, and a second object takes its place in the hot container. Here the hot container sits in the middle of the chain---it gives out one object and receives one back.

tip

Single End Chain is usually the better default. It produces the same kind of two-object chain, but leaves the hot container at the end (it gives out an object without receiving one back).

Single chain move: the hot object moves to another container while an object from a third container moves into the hot container

Parameters​

ParameterTypeRequiredDefaultDescription
partitionNameToExploreChainsWithinObjectGroupstringNo-If set, only objects in this partition are considered as the object that takes the hot object's place
specialColdContainerstringNo-If set, a fixed destination container for the hot object; otherwise all containers are explored

Behavior​

Given the hot container chosen by the common logic:

  1. Pick one object from the hot container (the "hot object").
  2. Pick two other containers, "other container 1" and "other container 2".
  3. Pick one object from "other container 1" (the "other object").
  4. Evaluate, at once, moving the hot object to "other container 2" and the other object into the hot container.

Every such combination is evaluated and the best chain is selected.

Complexity​

Roughly (objects ^ 2) * containers neighbors are evaluated.

Example​

Configure local search to use only the single chain move type:

LocalSearchSolverSpec localSearch;
localSearch.moveTypeList()->push_back(
    ProblemSolver::makeMoveTypeSpec(SingleChainMoveTypeSpec()));

solver.addSolver(localSearch);

(source)