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Opened 16 years ago

Closed 14 years ago

Last modified 14 years ago

#350 closed task (done)

Evaluate bias in certain permutation operators

Reported by: abeham Owned by:
Priority: medium Milestone: HeuristicLab 3.3.0
Component: ZZZ OBSOLETE: Permutation Version: 3.2
Keywords: Cc:

Description

Several permutation modification operators are biased in their selection of breakpoints, as the following code example shows:

breakPoint1 = random.Next(result.Length - 1); breakPoint2 = random.Next(breakPoint1 + 1, result.Length);

Assuming N = result.Length - 1, the probability of selecting breakPoint1 = N-1 and breakPoint2 = N is higher than breakPoint1 = 0 and breakPoint2 = 1, namely 1/N vs (1/N)*(1/N-1)

The influence of this bias on the optimization should be evaluated.

Change History (6)

comment:1 Changed 16 years ago by abeham

  • Status changed from new to assigned

comment:2 Changed 15 years ago by abeham

  • Owner abeham deleted
  • Status changed from assigned to new

first results with crossover operators show that the bias does not have negative effects, on the contrary, solution quality was better with bias.

Mutation operators have yet to be tested.

comment:3 Changed 15 years ago by swagner

  • Milestone changed from 3.2 to Iteration 0

Milestone 3.2 deleted

comment:4 Changed 14 years ago by abeham

  • Resolution set to fixed
  • Status changed from new to closed

Permutation operators have all been "reimplemented" using literature references. This ticket can be closed.

comment:5 Changed 14 years ago by swagner

  • Milestone changed from Iteration 4 to Current

Milestone Iteration 4 deleted

comment:11 Changed 14 years ago by swagner

  • Milestone changed from Current to HeuristicLab 3.3.0

Milestone Current deleted

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