git-svn-id: svn://scm.gforge.inria.fr/svnroot/paradiseo@609 331e1502-861f-0410-8da2-ba01fb791d7f
285 lines
18 KiB
C
285 lines
18 KiB
C
// "paradiseo.h"
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// (c) OPAC Team, LIFL, August 2005
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/*
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Contact: paradiseo-help@lists.gforge.inria.fr
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*/
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#ifndef __paradiseo_h_
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#define __paradiseo_h_
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#include <eo>
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#include <mo>
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//! \mainpage The ParadisEO-PEO Framework
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//!
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//! \section intro Introduction
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//!
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//! ParadisEO is a white-box object-oriented framework dedicated to the reusable design
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//! of parallel and distributed metaheuristics (PDM). ParadisEO provides a broad range of features including evolutionary
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//! algorithms (EA), local searches (LS), the most common parallel and distributed models and hybridization
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//! mechanisms, etc. This high content and utility encourages its use at European level. ParadisEO is based on a
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//! clear conceptual separation of the solution methods from the problems they are intended to solve. This separation
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//! confers to the user a maximum code and design reuse. Furthermore, the fine-grained nature of the classes
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//! provided by the framework allow a higher flexibility compared to other frameworks. ParadisEO is one of the rare
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//! frameworks that provide the most common parallel and distributed models. Their implementation is portable on
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//! distributed-memory machines as well as on shared-memory multiprocessors, as it uses standard libraries such as
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//! MPI, PVM and PThreads. The models can be exploited in a transparent way, one has just to instantiate their associated
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//! provided classes. Their experimentation on the radio network design real-world application demonstrate their
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//! efficiency.
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//!
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//! In practice, combinatorial optimization problems are often NP-hard, CPU time-consuming,
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//! and evolve over time. Unlike exact methods, metaheuristics allow to tackle large-size problems
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//! instances by delivering satisfactory solutions in a reasonable time. Metaheuristics are
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//! general-purpose heuristics that split in two categories: evolutionary algorithms (EA) and local
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//! search methods (LS). These two families have complementary characteristics: EA allow
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//! a better exploration of the search space, while LS have the power to intensify the search in
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//! promising regions. Their hybridization allows to deliver robust and better solutions
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//!
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//! Although serial metaheuristics have a polynomial temporal complexity, they remain
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//! unsatisfactory for industrial problems. Parallel and distributed computing is a powerful way
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//! to deal with the performance issue of these problems. Numerous parallel and distributed
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//! metaheuristics (PDM) and their implementations have been proposed, and are available on
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//! theWeb. They can be reused and adapted to his/her own problems. However, the user has to
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//! deeply examine the code and rewrite its problem-specific sections. The task is tedious, errorprone,
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//! takes along time and makes harder the produced code maintenance. A better way to
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//! reuse the code of existing PDM is the reuse through libraries. These are often
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//! more reliable as they are more tested and documented. They allow a better maintainability
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//! and efficiency. However, libraries do not allow the reuse of design.
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//!
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//! \section parallel_metaheuristics Parallel and distributed metaheuristics
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//!
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//! \subsection parallel_distributed Parallel distributed evolutionary algorithms
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//!
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//! Evolutionary Algorithms (EA) are based on the iterative improvement of a
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//! population of solutions. At each step, individuals are selected, paired and recombined in order
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//! to generate new solutions that replace other ones, and so on. As the algorithm converges,
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//! the population is mainly composed of individuals well adapted to the "environment", for
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//! instance the problem. The main features that characterize EA are the way the population is
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//! initialized, the selection strategy (deterministic/stochastic) by fostering "good" solutions,
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//! the replacement strategy that discards individuals, and the continuation/stopping criterion
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//! to decide whether the evolution should go on or not.
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//!
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//! Basically, three major parallel and distributed models for EA can been distinguished:
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//! the island (a)synchronous cooperative model, the parallel evaluation of the
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//! population, and the distributed evaluation of a single solution.
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//! <ul>
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//! <li> <i>Island (a)synchronous cooperative model</i>. Different EA are simultaneously deployed to
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//! cooperate for computing better and robust solutions. They exchange in an asynchronous
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//! way genetic stuff to diversify the search. The objective is to allow to delay the global
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//! convergence, especially when theEAare heterogeneous regarding the variation operators.
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//! The migration of individuals follows a policy defined by few parameters: the migration
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//! decision criterion, the exchange topology, the number of emigrants, the emigrants selection
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//! policy, and the replacement/integration policy.</li>
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//!
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//! <li> <i>Parallel evaluation of the population</i>. It is required as it is in general the most timeconsuming.
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//! The parallel evaluation follows the centralized model. The farmer applies
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//! the following operations: selection, transformation and replacement as they require a
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//! global management of the population. At each generation, it distributes the set of new
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//! solutions between differentworkers. These evaluate and return back the solutions and their
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//! quality values. An efficient execution is often obtained particularly when the evaluation
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//! of each solution is costly. The two main advantages of an asynchronous model over
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//! the synchronous model are: (1) the fault tolerance of the asynchronous model; (2) the
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//! robustness in case the fitness computation can take very different computation times (e.g.
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//! for nonlinear numerical optimization). Whereas some time-out detection can be used to
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//! address the former issue, the latter one can be partially overcome if the grain is set to very
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//! small values, as individuals will be sent out for evaluations upon request of the workers.</li>
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//!
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//! <li> <i>Distributed evaluation of a single solution</i>. The quality of each solution is evaluated in
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//! a parallel centralized way. That model is particularly interesting when the evaluation
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//! function can be itself parallelized as it is CPU time-consuming and/or IO intensive. In
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//! that case, the function can be viewed as an aggregation of a certain number of partial
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//! functions. The partial functions could also be identical if for example the problem to deal
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//! with is a data mining one. The evaluation is thus data parallel and the accesses to data
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//! base are performed in parallel. Furthermore, a reduction operation is performed on the
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//! results returned by the partial functions. As a summary, for this model the user has to
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//! indicate a set of partial functions and an aggregation operator of these.</li>
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//! </ul>
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//!
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//! \subsection parallel_ls Parallel distributed local searches
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//!
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//! \subsubsection local_searches Local searches
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//!
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//! All metaheuristics dedicated to the improvement of a single solution
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//! are based on the concept of neighborhood. They start from a solution randomly generated or
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//! obtained from another optimization algorithm, and update it, step by step, by replacing the
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//! current solution by one of its neighboring candidates. Some criterion have been identified to
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//! differentiate such searches: the heuristic internal memory, the choice of the initial solution,
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//! the candidate solutions generator, and the selection strategy of candidate moves. Three main
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//! algorithms of local search stand out: Hill Climbing (HC), Simulated
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//! Annealing (SA) and Tabu Search (TS).
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//!
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//! \subsubsection parallel_local_searches Parallel local searches
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//!
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//! Two parallel distributed models are commonly used in the literature: the parallel distributed
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//! exploration of neighboring candidate solutions model, and the multi-start model.
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//! <ul>
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//! <li><i>Parallel exploration of neighboring candidates</i>. It is a low-level Farmer-Worker model
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//! that does not alter the behavior of the heuristic. A sequential search computes the same
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//! results slower.At the beginning of each iteration, the farmer duplicates the current solution
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//! between distributed nodes. Each one manages some candidates and the results are returned to the farmer.
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//! The model is efficient if the evaluation of a each solution is time-consuming and/or there are a great
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//! deal of candidate neighbors to evaluate. This is obviously not applicable to SA since only one candidate
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//! is evaluated at each iteration. Likewise, the efficiency of the model for HC is not always guaranteed as
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//! the number of neighboring solutions to process before finding one that improves the current objective function may
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//! be highly variable.</li>
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//!
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//! <li> <i>Multi-start model</i>. It consists in simultaneously launching several local searches. They
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//! may be heterogeneous, but no information is exchanged between them. The resultswould
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//! be identical as if the algorithms were sequentially run.Very often deterministic algorithms
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//! differ by the supplied initial solution and/or some other parameters. This trivial model is
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//! convenient for low-speed networks of workstations.</li>
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//! </ul>
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//!
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//! \section hybridization Hybridization
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//!
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//! Recently, hybrid metaheuristics have gained a considerable interest. For many
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//! practical or academic optimization problems, the best found solutions are obtained by
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//! hybrid algorithms. Combinations of different metaheuristics have provided very powerful
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//! search methods. Two levels and two modes
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//! of hybridization have been distinguished: Low and High levels, and Relay and Cooperative modes.
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//! The low-level hybridization addresses the functional composition of a single optimization
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//! method. A function of a given metaheuristic is replaced by another metaheuristic. On the
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//! contrary, for high-level hybrid algorithms the different metaheuristics are self-containing,
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//! meaning no direct relationship to their internal working is considered. On the other hand,
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//! relay hybridization means a set of metaheuristics is applied in a pipeline way. The output
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//! of a metaheuristic (except the last) is the input of the following one (except the first).
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//! Conversely, co-evolutionist hybridization is a cooperative optimization model. Each metaheuristic
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//! performs a search in a solution space, and exchange solutions with others.
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//!
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//! \section paradiseo_goals Paradiseo goals and architecture
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//!
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//! The "EO" part of ParadisEO means Evolving Objects. EO is a C++ LGPL open source
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//! framework and includes a paradigm-free Evolutionary Computation library (EOlib)
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//! dedicated to the flexible design of EA through evolving objects superseding the most common
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//! dialects (Genetic Algorithms, Evolution Strategies, Evolutionary Programming and
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//! Genetic Programming). Furthermore, EO integrates several services including visualization
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//! facilities, on-line definition of parameters, application check-pointing, etc. ParadisEO is an
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//! extended version of the EO framework. The extensions include local search methods, hybridization
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//! mechanisms, parallelism and distribution mechanisms, and other features that
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//! are not addressed in this paper such as multi-objective optimization and grid computing. In
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//! the next sections, we present the motivations and goals of ParadisEO, its architecture and
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//! some of its main implementation details and issues.
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//!
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//! \subsection motivation Motivations and goals
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//!
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//! A framework is normally intended to be exploited by as many users as possible. Therefore,
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//! its exploitation could be successful only if some important user criteria are satisfied. The
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//! following criteria are the major of them and constitute the main objectives of the ParadisEO
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//! framework:
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//!
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//! <ul>
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//! <li><i>Maximum design and code reuse</i>. The framework must provide for the user a whole
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//! architecture design of his/her solution method. Moreover, the programmer may redo as
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//! little code as possible. This objective requires a clear and maximal conceptual separation
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//! between the solution methods and the problems to be solved, and thus a deep domain
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//! analysis. The user might therefore develop only the minimal problem-specific code.</li>
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//!
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//! <li><i>Flexibility and adaptability</i>. It must be possible for the user to easily add new features/
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//! metaheuristics or change existing ones without implicating other components. Furthermore,
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//! as in practice existing problems evolve and new others arise these have to be
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//! tackled by specializing/adapting the framework components.</li>
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//!
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//! <li><i>Utility</i>. The framework must allow the user to cover a broad range of metaheuristics,
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//! problems, parallel distributed models, hybridization mechanisms, etc.</li>
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//!
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//! <li><i>Transparent and easy access to performance and robustness</i>. As the optimization applications
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//! are often time-consuming the performance issue is crucial. Parallelism and
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//! distribution are two important ways to achieve high performance execution. In order to
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//! facilitate its use it is implemented so that the user can deploy his/her parallel algorithms in
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//! a transparent manner. Moreover, the execution of the algorithms must be robust to guarantee
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//! the reliability and the quality of the results. The hybridization mechanism allows
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//! to obtain robust and better solutions.</li>
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//!
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//! <li><i>Portability</i>. In order to satisfy a large number of users the framework must support
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//! different material architectures and their associated operating systems.</li>
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//! </ul>
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//!
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//! \subsection architecture ParadisEO architecture
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//!
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//! The architecture of ParadisEO is multi-layer and modular allowing to achieve the objectives
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//! quoted above. This allows particularly a high flexibility and adaptability, an
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//! easier hybridization, and more code and design reuse. The architecture has three layers
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//! identifying three major categories of classes: <i>Solvers</i>, <i>Runners</i> and <i>Helpers</i>.
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//! <ul>
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//! <li><i>Helpers</i>. Helpers are low-level classes that perform specific actions related to the evolution
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//! or search process. They are split in two categories: <i>Evolutionary helpers (EH)</i>
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//! and <i>Local search helpers (LSH)</i>. EH include mainly the transformation, selection and
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//! replacement operations, the evaluation function and the stopping criterion. LSH can be
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//! generic such as the neighborhood explorer class, or specific to the local search metaheuristic
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//! like the tabu list manager class in the Tabu Search solution method. On the
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//! other hand, there are some special helpers dedicated to the management of parallel and
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//! distributed models 2 and 3, such as the communicators that embody the communication
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//! services.
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//!
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//! Helpers cooperate between them and interact with the components of the upper layer
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//! i.e. the runners. The runners invoke the helpers through function parameters. Indeed,
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//! helpers have not their own data, but they work on the internal data of the runners.</li>
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//!
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//! <li><i>Runners</i>. The Runners layer contains a set of classes that implement the metaheuristics
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//! themselves. They perform the run of the metaheuristics from the initial state or
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//! population to the final one. One can distinguish the <i>Evolutionary runners (ER)</i> such as
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//! genetic algorithms, evolution strategies, etc., and <i>Local search runners (LSR)</i> like tabu
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//! search, simulated annealing and hill climbing. Runners invoke the helpers to perform
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//! specific actions on their data. For instance, an ER may ask the fitness function evaluation
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//! helper to evaluate its population. An LSR asks the movement helper to perform
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//! a given movement on the current state. Furthermore, runners can be serial or parallel
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//! distributed.</li>
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//!
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//! <li><i>Solvers</i>. Solvers are devoted to control the evolution process and/or the search. They
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//! generate the initial state (solution or population) and define the strategy for combining
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//! and sequencing different metaheuristics. Two types of solvers can be distinguished.
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//! <i>Single metaheuristic solvers (SMS)</i> and <i>Multiple metaheuristics solvers (MMS)</i>. SMSs
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//! are dedicated to the execution of only one metaheuristic.MMS are more complex as they
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//! control and sequence several metaheuristics that can be heterogeneous. Solvers interact with
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//! the user by getting the input data and delivering the output (best solution, statistics,
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//! etc).</li>
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//! </ul>
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//!
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//! According to the generality of their embedded features, the classes of the architecture split
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//! in two major categories: <i>Provided classes</i> and <i>Required classes</i>. Provided classes embody
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//! the factored out part of the metaheuristics. They are generic, implemented in the framework,
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//! and ensure the control at run time. Required classes are those that must be supplied by the
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//! user. They encapsulate the problem-specific aspects of the application. These classes are
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//! fixed but not implemented in ParadisEO. The programmer has the burden to develop them
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//! using the OO specialization mechanism.
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//!
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//! \section tutorials ParadisEO-PEO Tutorials
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//!
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//! The basisc of the ParadisEO framework philosophy are exposed in a few simple tutorials:
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//! <ul>
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//! <li>
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//! <a href="lesson1/html/main.html" style="text-decoration:none;"> creating a simple ParadisEO evolutionary algorithm</a>;
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//! </li>
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//! </ul>
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//! All the presented examples have as case study the traveling salesman problem (TSP). Different operators and auxiliary objects were designed,
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//! standing as a <a href="lsnshared/html/index.html" target="new" style="text-decoration:none;">common shared source code base</a>. While not being
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//! part of the ParadisEO-PEO framework, it may represent a startpoint for a better understanding of the presented tutorials.
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#include "core/peo_init.h"
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#include "core/peo_run.h"
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#include "core/peo_fin.h"
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#include "core/eoVector_comm.h"
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#include "peoEA.h"
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/* Parallel steps of the E.A. */
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#include "peoSeqTransform.h"
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#include "peoParaSGATransform.h"
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#include "peoSeqPopEval.h"
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#include "peoParaPopEval.h"
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/* Cooperative island model */
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#include "core/ring_topo.h"
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#include "peoAsyncIslandMig.h"
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#include "peoSyncIslandMig.h"
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/* Synchronous multi-start model */
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#include "peoSyncMultiStart.h"
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#endif
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