Particle swarm optimization: Difference between revisions

The goal of parameter selection is to ensure that the global minimum is discriminated from any local minima, and that the minimum is accurately determined, and that convergence is achieved with acceptibleacceptable resource usage. To provide a common basis for comparing implementations, the following test cases are recommended:

<langsyntaxhighlight lang="cpp">#include <algorithm>

}</langsyntaxhighlight>

<langsyntaxhighlight Dlang="d">import std.math;

}</langsyntaxhighlight>

<langsyntaxhighlight lang="go">package main

<langsyntaxhighlight Jlang="j">load 'format/printf'

reportState=: 'Iteration: %j\nGlobalBestPosition: %j\nGlobalBestValue: %j\n' printf 3&{.</langsyntaxhighlight>

Apply to McCormick Function:<langsyntaxhighlight Jlang="j"> require 'trig'

GlobalBestValue: _1.91322</langsyntaxhighlight>

<langsyntaxhighlight Jlang="j"> michalewicz =: 3 : '- +/ (sin y) * 20 ^~ sin (>: i. #y) * (*:y) % pi'

GlobalBestValue: _1.8013</langsyntaxhighlight>

<langsyntaxhighlight lang="java">import java.util.Arrays;

}</langsyntaxhighlight>

<langsyntaxhighlight lang="julia">using Optim

</langsyntaxhighlight>{{out}}

2.312291 seconds (3.52 M allocations: 153.253 MiB, 0.49% gc time)

<langsyntaxhighlight lang="scala">// version 1.1.51

}</langsyntaxhighlight>

<langsyntaxhighlight lang="oorexx">/* REXX ---------------------------------------------------------------

::requires rxmath library</langsyntaxhighlight>

=={{header|PhixPerl}}==

{{trans|KotlinRaku}}

use constant infPI => 2 1e308*1e308 atan2(1, 0);

maxsmy($fn, =%y) {PI,= PI}@_;

paramsmy =$p {0.3, 0.3, 0.3 = $y{'p'};

nParticlesmy $n = 1000$y{'n'};

{x,y}my $rand_g = state[GBPOS]rand;

<langsyntaxhighlight lang="racket">#lang racket/base

(PSO (Michalewitz 10) 1000 30 (box 0) (box pi) #:ω 0.3 #:φ_p 0.3 #:φ_g 0.3 #:> <)</langsyntaxhighlight>

<langsyntaxhighlight lang="rexx">/*REXX program calculates Particle Swarm Optimization as it migrates through a solution.*/

numeric digits length( pi() ) - 1 length(.) /*use the number of decimal digs in pi.*/

#= 0; call refine x, y /*the#: number ofREFINE iterations; for invoke REFINE. */

refine: parse arg xx,yy; h= d * .5 /*compute ½ distance. */

do y=yy-d to yy+d by h; f= f(x, y); if f>=minF then iterate

new= fmt(x) fmt(y) fmt(f); if new=old then return 1

#= # + 1; say center(#,13) new /*bump #iter.; iterations.show new*/

say center(#,13) new minF= f; minX= x; minY= y; old= new /*show " " assign new values. */

fmt: ?= format(arg(1), , sDigs); L= length(?); if pos(., ?)\==0 then ?= strip( strip(?, 'T', 0), "T", .); return left(?, L)

r2r: return arg(1) // ( pi() * 2) /*normalize radians ───► a unit circle.*/

sin: procedure; arg x; x= r2r(x); z= x; xx= x*x; do k=2 by 2 until p=z; p=z; x= -x* xx/ (k*(k+1)); z= z+x; end; return z</langsyntaxhighlight>