Questions tagged [local-search]

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Node swap and edge swap for TSP

When devising heuristics for the TSP I often see edge exchange algorithms suggested. But I also find them a bit hard to understand and somewhat cumbersome to implement. When I think about a TSP, I ...
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1 vote
1 answer
57 views

What methods exist for tree search over a large complex state representation?

Tree search over a state space often assumes that the state can be represented compactly and repeated in each node of the search tree. Suppose I have a large simulation with 100000's of entities each ...
10 votes
4 answers
921 views

Is there an open-source equivalent to LocalSolver?

I have a constraint programming problem that is easy to formulate and solve (with high solution quality) in LocalSolver. However, I would really prefer to use something open source for ...
3 votes
0 answers
64 views

How can I use a local search meta heuristic after completing construction heuristic?

I'm investigating how I can combine a construction heuristic and a local search metaheuristic to quickly solve Capacitated Split Delivery Veichle Routing Problem (CSDVRP). The construction heuristic ...
  • 207
5 votes
2 answers
281 views

Can Local Search Operators be formulated as a Mixed Integer Program?

Consider the situation of Vehicle Routing. Once we have an initial solution, one can apply various local search moves to improve it. For example: Removing a single customer from a route and inserting ...
2 votes
1 answer
68 views

How to do Local search when using Greedy random heuristics for GAP

If I want to try a greedy randomized adaptive search procedure for the generalized assignment problem (assign N tasks to N workers to minimize the total costs), the GRASP method requires 2 parts ...
5 votes
2 answers
683 views

Book to learn metaheuristics

I want to learn about metaheuristics and start building one to solve combinatorial optimization which is pretty hard to solve. I am looking for book recommendation or any learning experience to learn ...
  • 573
3 votes
0 answers
119 views

When to use Tabu Search or Genetic Algorithms and when not?

Are there any rules of thumb about when to implement which? For example, I am trying to solve OR scheduling problems. I see that majority of people have implemented Genetic Algorithms. However, more ...
0 votes
1 answer
174 views

Question re Tabu Search

I am working through the Udemy course "Optimizing Travelling Salesman and Vehicle Routing Problems". A part of the course is looking at Tabu search as a solution to the vehicle routing ...
  • 117
8 votes
0 answers
140 views

Traveling Salesman Problem: determine k-exchange feasibility

Given a current solution $S$ and a $k$-exchange move $(v_1, .., v_{2k+1})$ with $v_1 = v_{2k+1}$, $v_i \neq v_j$, $(v_i, v_{i+1}) \in E(S)$ iff $i$ odd, i.e. we remove all edges $(v_i, v_{i+1})$ for $...
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4 votes
2 answers
211 views

When solving many MILPs how to assign CPU cores to solver instances?

Let's say I have an 16 core machine and many roughly equally hard MILP problems and enough RAM. The latency of solving doesn't matter. With how many cores should I start solvers on to maximize ...
4 votes
2 answers
159 views

Increase the dimension to ease the local search?

Local search, as the name suggests, takes a local angle to the optimization problem. In deep learning, an adjacent field, the "local minima" problem is frequently mitigated by increasing the ...
8 votes
5 answers
731 views

Paper suggestions on local search algorithms

I am looking for papers (or any resources) that go deep into the details of implementing local search algorithms. I don't want an introductory paper on the subject. Rather, I would prefer a survey ...
7 votes
4 answers
616 views

Learning local search operator selection

I'm just reading [1]. The authors use a neural network to solve capacitated vehicle routing problems through iterative generation of tours by solving a price-collecting traveling salesman problem in ...
  • 491
3 votes
1 answer
173 views

PSO. Hyperparameter Optimization for Similar Problems

I am doing a project where I am using Particle Swarm Optimization (PSO) for a design optimization problem. Naturally, in there I had to conduct hyperparameter optimization to find the most optimal ...
4 votes
1 answer
167 views

How to implement a local search with different operators?

I read some papers on local search. I remark that several authors use different move operators. However, the pseudo-code I found on google only uses one operator. I am wondering how to implement the ...
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1 vote
2 answers
234 views

How to correct this scheduling algorithm?

I have a scheduling problem to solve. It's a resource-constrained project scheduling problem with time-varying resource availabilities. The objective is minimizing tardiness. The full detailed model ...
13 votes
1 answer
272 views

In Local Search, which reheating techniques have a good track record?

Given a fast-stepping Local Search (such as Simulated Annealing or Late Acceptance), which reheating approach is proven to work well? Generally speaking, reheating works like this: if [a condition is ...
3 votes
1 answer
194 views

On what kind of problems a local search may perform better than MIP / CP techniques? [closed]

In combinatorial optimization, on what type of problem a local search may lead to better & quicker solutions than usual mixed-integer programming and constraint programming techniques ? By type ...
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