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LocalSolver is a company which provides a global optimization solver, combining exact and heuristic techniques.

The benchmarks on their website are quite impressive. For example, they claim they can solve large TSPs within 10 seconds with gaps smaller than 5% in average :

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  1. Does anyone have any experience with LocalSolver, and what are the pro's and con's ?

  2. Are there any peer reviewed publications where these benchmarks can be found ? It would be interesting to see if there are any comparisons with heuristics and metaheuristics. Localsolver performs local search after all !

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  • $\begingroup$ I had a little search on their website and google scholar and found lots of papers talking about their approach in designing the solver(authors are the designers of the LocalSolvers) and found many application papers both in English and French(!). If you search for the designer's name (Thierry Benoist, Frédéric Gardi - these guys have google scholar accounts) you will find the source of all those papers. $\endgroup$ – Oguz Toragay May 11 at 23:19
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    $\begingroup$ swmath.org/software/4850 <--- here is a list of academic papers about the solver. $\endgroup$ – Oguz Toragay May 11 at 23:43
  • $\begingroup$ I also read somewhere that they (Localsolver) claim to have best solution approach to solve non-linear optimization problems in particular. $\endgroup$ – Divyam Aggarwal May 12 at 6:16
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    $\begingroup$ Note also that LocalSolver is a user on this site. $\endgroup$ – LarrySnyder610 May 12 at 14:34
  • $\begingroup$ Yes, I think it is great if they can contribute somehow on this site. It would be interesting to compare their pros and cons, with users. Perhaps it could help them as well identify potential improvements. $\endgroup$ – Kuifje May 12 at 14:41
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Here is a quick summary about the pros and cons of LocalSolver, a global optimization solver combining exact and heuristic techniques. Please note that this summary is written by the LocalSolver team itself, as asked by Kuifje in the comment above.

Pros:

  • You will model your problem using nonlinear and set-based mathematical modeling APIs. Then, your math model will be closer to the real-life problem, more concise and easier to maintain. For an example of what means "set-based modeling", have a look to the TSP model described here. LocalSolver also supports the use of external functions in your model (also known as black-box optimization) and offers multiobjective modeling features.
  • Having properly modeled your problem for LocalSolver, you will get solutions faster and your model will be more scalable than when using MILP solvers, thanks to innovative heuristics. In addition, LocalSolver offers (global) dual bounds.

Cons:

  • You have to reformulate your problem by using the appropriate LocalSolver modeling constructs, and following LocalSolver modeling best practices.
  • Don't give MILP-like models to LocalSolver, especially LP or MPS files, to hope getting good results.

State-of-the-art MIP solvers remain better than LocalSolver when it comes to solving pure linear problems and then nearly linear problems (that is, problems that allow good linear approximations). Because the LP codes (simplex, interior-point) used inside these MIP solvers are still stronger than the ones inside LocalSolver (note that we work hard to decrease this gap each year). This performance gap is noticeable for large-scale, ill-posed linear programs. Now, when problems become more combinatorial (in particular: routing, scheduling, packing, assignment) or more nonlinear/nonconvex/nonsmooth in the continuous space, LocalSolver is a tool of choice which deserves to be considered for your optimization project.

Additional non-technical strengths of LocalSolver that our users mention: the dedicated and reactive support offered by the R&D team to model and solve at best your problems using LocalSolver; an aggressive roadmap with two new releases per year with constant performance improvements and new features; a simple, competitive, flexible licensing & pricing.

For examples of problems modeled using LocalSolver, have a look to https://www.localsolver.com/docs/last/exampletour/index.html.

Check out the following links for some benchmarks against MIP solvers:

You can reproduce the results given in these benchmarks by registering and asking for free trial licenses on the LocalSolver website: https://www.localsolver.com/account.html.

Note that the technical papers related to LocalSolver which you can find on the web are largely outdated. We don't publish anymore about LocalSolver since several years (mostly for confidentiality reasons).

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    $\begingroup$ Does LocalSolver offer dual bounds, as well nowadays? That is, can it provide gap information? $\endgroup$ – Robert Schwarz May 14 at 6:47
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    $\begingroup$ @LocalSolver Thanks for your feedback ! LocalSolver seems like a nice tool with many strengths. Also, I enjoyed your recent posts regarding the largest empty rectangle, nice stuff. $\endgroup$ – Kuifje May 14 at 7:06
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    $\begingroup$ @RobertSchwarz Yes, LocalSolver offers (global) dual bounds as well. For example, have a look to localsolver.com/news.html?id=96. $\endgroup$ – LocalSolver May 14 at 9:52
  • $\begingroup$ @Kuifje Thanks a lot for your kind words and encouragements. This post was about recreative, funny problems but shows quite well LocalSolver capabilities as global optimization solver. $\endgroup$ – LocalSolver May 14 at 9:58

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