From 427271ab0314f645a6cbc0a044db565188b6aa4e Mon Sep 17 00:00:00 2001
From: Jafagervik <jorgenafagervik@gmail.com>
Date: Sat, 20 Apr 2024 18:01:53 +0200
Subject: [PATCH 1/2] simulated annealing

---
 src/EvoLP.jl         |  2 ++
 src/algorithms/sa.jl | 54 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+)
 create mode 100644 src/algorithms/sa.jl

diff --git a/src/EvoLP.jl b/src/EvoLP.jl
index 1d2e828..d3f7845 100644
--- a/src/EvoLP.jl
+++ b/src/EvoLP.jl
@@ -20,6 +20,7 @@ include("testfunctions.jl")
 
 include("algorithms/ga.jl")
 include("algorithms/ea.jl")
+include("algorithms/sa.jl")
 include("algorithms/swarm.jl")
 
 include("deprecated.jl")
@@ -32,6 +33,7 @@ export Particle, normal_rand_particle_pop, unif_rand_particle_pop  # Particles
 
 # Algorithms
 export GA, GA!
+export SA
 export oneplusone, oneplusone!
 export PSO, PSO!
 
diff --git a/src/algorithms/sa.jl b/src/algorithms/sa.jl
new file mode 100644
index 0000000..1078ab6
--- /dev/null
+++ b/src/algorithms/sa.jl
@@ -0,0 +1,54 @@
+"""
+    SA(f, pop, k_max, S, C, M; T_init)
+
+Simulated annealing.
+
+## Arguments
+- `f::Function`: objective function to **minimise**.
+- `population::AbstractVector`: a list of vector individuals.
+- `k_max::Integer`: number of iterations.
+- `S::ParentSelector`: one of the available [`ParentSelector`](@ref).
+- `C::CrossoverMethod`: one of the available [`CrossoverMethod`](@ref).
+- `M::MutationMethod`: one of the available [`MutationMethod`](@ref).
+- `T₀::Real=100.0`: initial temperature
+- `α::Real=0.99`: cooling rate
+
+Returns a [`Result`](@ref).
+"""
+function SA(
+    f::Function,
+    population::AbstractVector,
+    k_max::Integer,
+    S::ParentSelector,
+    C::Recombinator,
+    M::Mutator;
+    T₀::Real=100.0,
+    α::Real=0.99
+)
+    fx = Inf
+    best_ind = copy(population)  # Initialize the best individual
+    T = T₀ # Initialize the temperature
+
+    runtime = @elapsed begin
+        for _ in 1:k_max
+            c = mutate(M, population)
+            fc = f(c)
+            ΔE = fc - fx  # Calculate the difference in objective function values
+
+            # Acceptance probability function
+            if ΔE < 0 || rand() < exp(-ΔE / T)
+                population = copy(c)
+                fx = fc
+            end
+
+            fx < f(best_ind) && (best_ind = copy(population))
+
+            T *= α
+        end
+    end
+
+    n_evals = k_max
+
+    return Result(fx, best_ind, [best_ind], k_max, n_evals, runtime)
+end
+

From e3fb677786b8822dcf78ed6c23a37ee411d20ffb Mon Sep 17 00:00:00 2001
From: Jafagervik <jorgenafagervik@gmail.com>
Date: Sat, 20 Apr 2024 18:04:44 +0200
Subject: [PATCH 2/2] remove comments

---
 src/algorithms/sa.jl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/algorithms/sa.jl b/src/algorithms/sa.jl
index 1078ab6..0a13335 100644
--- a/src/algorithms/sa.jl
+++ b/src/algorithms/sa.jl
@@ -26,8 +26,8 @@ function SA(
     α::Real=0.99
 )
     fx = Inf
-    best_ind = copy(population)  # Initialize the best individual
-    T = T₀ # Initialize the temperature
+    best_ind = copy(population)
+    T = T₀
 
     runtime = @elapsed begin
         for _ in 1:k_max