Particle swarm optimization: Difference between revisions

=={{header|Julia}}==

<lang julia>using Optim

const mcclow = [-1.5, -3.0]

const mccupp = [4.0, 4.0]

const miclow = [0.0, 0.0]

const micupp = Float64.([pi, pi])

const npar = [100, 1000]

const x0 = [0.0, 0.0]

michalewicz(x, m=10) = -sum(i -> sin(x[i]) * (i * sin( x[i]^2/pi))^(2*m), 1:length(x))

mccormick(x) = sin(x[1] + x[2]) + (x[1] - x[2])^2 - 1.5 * x[1] + 2.5 * x[2] + 1

println(optimize(mccormick, x0, ParticleSwarm(;lower=mcclow, upper=mccupp, n_particles=npar[1])))

@time optimize(mccormick, x0, ParticleSwarm(;lower=mcclow, upper=mccupp, n_particles=npar[1]))

println(optimize(michalewicz, x0, ParticleSwarm(;lower=miclow, upper=micupp, n_particles=npar[2])))

@time optimize(michalewicz, x0, ParticleSwarm(;lower=miclow, upper=micupp, n_particles=npar[2]))

</lang>{{out}}

<pre>

Results of Optimization Algorithm

* Algorithm: Particle Swarm

* Starting Point: [0.0,0.0]

* Minimizer: [-0.5471975503990738,-1.5471975447742121]

* Minimum: -1.913223e+00

* Iterations: 1000

* Convergence: false

* |x - x'| ≤ 0.0e+00: false

|x - x'| = NaN

* |f(x) - f(x')| ≤ 0.0e+00 |f(x)|: false

|f(x) - f(x')| = NaN |f(x)|

* |g(x)| ≤ 1.0e-08: false

|g(x)| = NaN

* Stopped by an increasing objective: false

* Reached Maximum Number of Iterations: true

* Objective Calls: 101001

* Gradient Calls: 0

0.087319 seconds (228.91 k allocations: 12.098 MiB, 59.41% gc time)

Results of Optimization Algorithm

* Algorithm: Particle Swarm

* Starting Point: [0.0,0.0]

* Minimizer: [2.202905520771759,1.5707963264041795]

* Minimum: -1.801303e+00

* Iterations: 1000

* Convergence: false

* |x - x'| ≤ 0.0e+00: false

|x - x'| = NaN

* |f(x) - f(x')| ≤ 0.0e+00 |f(x)|: false

|f(x) - f(x')| = NaN |f(x)|

* |g(x)| ≤ 1.0e-08: false

|g(x)| = NaN

* Stopped by an increasing objective: false

* Reached Maximum Number of Iterations: true

* Objective Calls: 1001001

* Gradient Calls: 0

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

</pre>