The domain of metaheuristic optimization has become vibrant due to a flood of new algorithms using a new nature-inspired metaphor but lacking clear methodological novelty. The Criticism behind the development of these algorithms has reached such an extent that the critics started to assert that all novel algorithms are only copies of already developed ones. In this study, we try to show that the situation is not so black and white. Therefore, we define a strong equivalence theorem for estimating the similarity between two nature-inspired metaheuristics, according to which two algorithms are equivalent if, and only if, the cosine similarity of their phenotypic and genotypic feature vectors, characterizing their behavior by searching for the optimal solutions, is above some threshold. On the theorem basis, a framework is developed for identifying the equivalence between nature-inspired metaheuristics. Extensive experimental work using the framework has shown that searching for conditions to achieve the high similarity of the more well-known nature-inspired metaheuristics is hard, or even not possible to achieve, in the limited computational environments.
Figures & tables
Figure 1: Workflow of the framework for identifying strong equivalence between NI metaheuristics.
Switch
Argument
−a to −c
Various algorithm’s parameters
−g
Maximum number of generations
−d
Problem dimension
−n
Number of parameters
−r
Maximum number of independent runs
−s
Random generator seed
Table 1: Passing parameter.
Figure 2: Scheme of the framework for identifying the similarity of NI algorithms, where Alg1 denotes the control and Alg2 the controlled algorithm.
Algorithm
Representation
Variation
Selection
Population
Adaptation
of individuals
operator
scheme
model
(optional)
accPSO
Floating-point
Eq. ( 5 )
global best
1-population
n/a
accFA
Floating-point
Eq. ( 8 )
global best
1-population
n/a
PSO
Floating-point
Eq. ( 2 )
one-to-one
2-populations
n/a
FA
Floating-point
Eq. ( 7 )
global best
1-population
n/a
BA
Floating-point
Eq. ( 9 )
SA -selection 1 1 1 SA -selection Excluded when Ai=1 .
1-population
Eq. ( 13 ), GRW 2 2 2 GRW excluded when ri=0 .
Table 2: Summary characteristics of the NI metaheuristics in the study.
Algorithm
Initial
Parameter control
Domain
1
2
3
1
2
3
1
2
3
accPSO
α0
β0
n/a
FIX
FIX
n/a
[0.1,1.0]
[0.1,1.0]
n/a
accFA
α0
β0
n/a
FIX
FIX
n/a
[0.1,1.0]
[0.1,1.0]
n/a
PSO
w
c1
c2
FIX
FIX
FIX
[0.4,0.9]
[1.5,2.5]
[1.5,2.5]
FA
α0
β0
γ
DET
META
FIX
[0.1,1.0]
[0.5,1.5]
[0.1,1.0]
BA
A0
γ
n/a
DET
META
n/a
[0.7,1.2]
[0.1,0.3]
n/a
Table 3: Parameter analysis of the observed NI metaheuristic algorithm.
Figure 3: Simplified syntax diagrams of the variation operators used in the observed NI metaheuristic algorithms.
Table 4: Simplified BNF notation of the variation operator syntax.
⟨weight⟩
Parameterw
⟨fixed⟩
No parameter control
⟨stochastic⟩
Parameter control involves randomness (e.g., ϵ1⋅c1 or ϵ2⋅c2 )
⟨deterministic⟩
Deterministic parameter control (e.g., α in FA)
⟨metaphor-based⟩
Metaphor-based parameter control (e.g., β(r) in FA, rˉ in BA)
⟨epsilon⟩
Random number drawn from uniform distributionϵ∈U(0,1)
⟨mean_pulse_rate⟩
Average pulse rate
Table 5: Meaning of the undefined non-terminals.
Table 6: Characteristics of the PC and the correlation coefficient interpretation.
Role
Algorithm
Metric
Min
Max
Mean
StDev
Median
Control
accPSO
α
0.4999
0.5001
0.5000
<0.0001
0.5000
β
0.2000
0.2000
0.2000
0.0000
0.2000
Fitness
-0.1197
-0.0134
-0.0618
0.0269
-0.0577
Controlled
accFA
α
0.4999
0.5001
0.5000
<0.0001
0.5000
β
0.2000
0.2000
0.2000
0.0000
0.2000
Fitness
-0.1197
-0.0134
-0.0618
0.0269
-0.0577
Table 7: The results of the Meta-DE by parameter setting analysis in CS-1.
Algorithm
Parameter
Simcos
SimSMAPE
ρ
SimkNN
SimSVM
SimRF
accFA
Min
1.0000
1.0000
1.0000
n/a
n/a
n/a
Max
1.0000
1.0000
1.0000
n/a
n/a
n/a
Mean
1.0000
1.0000
1.0000
1.0000
1.0000
1.0000
StDev
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
Median
1.0000
1.0000
1.0000
n/a
n/a
n/a
Table 8: The results of the statistical analysis according to similarity metrics for identifying the strong equivalence between the accPSO and accFA in CS-1.
Role
Algorith.
Metric
Min
Max
Mean
StDev
Median
Control
accPSO
α
0.4999
0.5001
0.5000
<0.0001
0.5000
β
0.2000
0.2000
0.0000
0.2000
0.2000
Fitness
-0.1197
-0.0134
-0.0618
0.0269
-0.0577
Controlled
PSO
w
0.4740
0.7760
0.6322
0.0780
0.6251
c1
1.5000
1.8624
1.5511
0.1084
1.5000
c2
1.5000
2.5000
2.3575
0.2193
2.4712
Table 9: The results of the Meta-DE by parameter setting analysis in CS-2.
Algorithm
Parameter
Simcos
SimSMAPE
ρ
SimkNN
SimSVM
SimRF
PSO
Min
0.9674
0.9997
0.9673
n/a
n/a
n/a
Max
0.9818
0.9999
0.9819
n/a
n/a
n/a
Mean
0.9756
0.9998
0.9756
0.0000
0.0000
0.0000
StDev
0.0038
<0.0001
0.0038
0.0000
0.0000
0.0000
Median
0.9764
0.9998
0.9764
n/a
n/a
n/a
FA
Min
0.1410
0.9991
0.1351
n/a
n/a
n/a
Table 10: The results of the statistical analysis according to the similarity metrics for identifying the strong equivalence using the accPSO as the control algorithm in CS-2.
Table 11: The comparison of the variation operators from the set NIA(CS-2) .
Role
Algorit.
Metric
Min
Max
Mean
StDev
Median
Control
PSO
w
0.4954
0.5000
0.4999
0.0004
0.5000
c1
1.5000
1.5002
1.5000
<0.0001
1.5000
c2
1.5000
1.5106
1.5001
0.0009
1.5000
Fitness
<−0.0001
<−0.0001
<−0.0001
<0.0001
<−0.0001
Controlled
accPSO
α
0.1696
1.0000
0.9027
0.2185
1.0000
β
0.1301
0.1936
0.1513
0.0109
0.1502
Table 12: The results of the Meta-DE by parameter setting analysis in CS-3.
Algorithm
Parameter
Simcos
SimSMAPE
ρ
SimkNN
SimSVM
SimRF
accPSO
Min
0.9549
0.9997
0.9561
n/a
n/a
n/a
Max
0.9924
0.9999
0.9924
n/a
n/a
n/a
Mean
0.9862
0.9999
0.9863
0.0000
0.0000
0.0000
StDev
0.0045
0.0000
0.0044
0.0000
0.0000
0.0000
Median
0.9869
0.9999
0.9869
n/a
n/a
n/a
FA
Min
0.1541
0.9991
0.1499
n/a
n/a
n/a
Table 13: The results of the statistical analysis according to the similarity metrics for identifying the strong equivalence between the PSO as control algorithm in CS-3.
Figure 4: Population descriptive metrics.
Figure 5: Individual descriptive metrics.
Role
Algorit.
Metric
Min
Max
Mean
StDev
Median
Control
BA
A
1.0000
1.0000
1.0000
0.0000
1.0000
γ
0.1000
0.1805
0.1148
0.0199
0.1041
Fitness
-1.5632
-0.3465
-1.0069
0.2497
-1.0332
Controlled
accPSO
α
1.0000
1.0000
1.0000
0.0000
1.0000
β
0.3911
0.9629
0.7815
0.0569
0.7869
Fitness
-0.2243
-0.0557
-0.1375
0.0341
-0.1412
Table 14: The results of the Meta-DE by parameter setting analysis in CS-4.
Algorithm
Parameter
Simcos
SimSMAPE
ρ
SimkNN
SimSVM
SimRF
accPSO
Min
0.8605
0.9996
0.8607
n/a
n/a
n/a
Max
0.9575
0.9998
0.9573
n/a
n/a
n/a
Mean
0.9069
0.9997
0.9050
0.0000
0.0000
0.0000
StDev
0.0142
0.0000
0.0147
0.0000
0.0000
0.0000
Median
0.9064
0.9997
0.9042
n/a
n/a
n/a
PSO
Min
0.6173
0.9993
0.6108
n/a
n/a
n/a
Table 15: The results of the statistical analysis according to the similarity metrics for identifying the strong equivalence between the BA as the control algorithm in CS-4.
Large language models (LLMs) are increasingly being employed as variation operators in metaheuristics, generating or modifying candidate solutions, heuristics, or programs inside iterative search loops. This shift reframes variation as a model call conditioned on different types of information. We introduce an operator-level framework with two descriptors: (1) the type of prompt-conditioning information at variation time (Numeric, Symbolic, Linguistic), and (2) artifact persistence, identifying what survives the model call (Transient, Amortized, Transfer). The tutorial shows how to classify, build, and select these operators through a worked build template, a method survey, an evidence table, and a cost-aware decision guide.
Camilo Chacón Sartori, Guillem Rodríguez-Corominas, Christian Blum
Apeiron Intelligence, Barcelona, Spain · Artificial Intelligence Research Institute (IIIA-CSIC), Bellaterra, Spain · Universitat Politècnica de Catalunya (UPC), Barcelona, Spain
Metaheuristic algorithms such as Particle Swarm Optimization (PSO) and Evolutionary Algorithms (EA) excel at exploring solution spaces but lack mechanisms to accumulate and reuse procedural knowledge from successful search trajectories. This paper proposes Associative Constructive Evolution (ACE), a framework that enhances metaheuristics through learned generative guidance. ACE introduces a Generative Construction Automaton (GCA) -- a probabilistic model over operation sequences -- coupled with the base metaheuristic in a synergistic loop: the metaheuristic explores and provides trajectory samples, while the GCA consolidates successful patterns and guides future exploration. Three mechanisms realize this cooperation: Hebbian weight consolidation that strengthens associations between co-successful operations, guided sampling that biases search toward learned high-quality regions, and symbolic abstraction that extracts frequent patterns into reusable macro-operations. Experiments integrating ACE with EA and PSO on molecular design and maze navigation demonstrate consistent improvements. ACE-PSO achieves a 27.5% increase in success rate while reducing convergence time by 49.6%. In molecular design, ACE-EA improves fitness by 10.1% with 126 chemically interpretable macro-operations automatically discovered.
Shanxian Lin, Yuichi Nagata, Haichuan Yang
Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Japan
Social insect colonies and ensemble machine learning methods represent two of the most successful examples of decentralized information processing in nature and computation respectively. Here we develop a rigorous mathematical framework demonstrating that ant colony decision-making and random forest learning are isomorphic under a common formalism of stochastic ensemble intelligence. We show that the mechanisms by which genetically identical ants achieve functional differentiation -- through stochastic response to local cues and positive feedback -- map precisely onto the bootstrap aggregation and random feature subsampling that decorrelate decision trees. Using tools from Bayesian inference, multi-armed bandit theory, and statistical learning theory, we prove that both systems implement identical variance reduction strategies through decorrelation of identical units. We derive explicit mappings between ant recruitment rates and tree weightings, pheromone trail reinforcement and out-of-bag error estimation, and quorum sensing and prediction averaging. This isomorphism suggests that collective intelligence, whether biological or artificial, emerges from a universal principle: \textbf{randomized identical agents + diversity-enforcing mechanisms → emergent optimality}.
Ernest Fokoué, Gregory Babbitt, Yuval Levental
School of Mathematics and Statistics, Rochester Institute of Technology · Gosnell School of Life Sciences, Rochester Institute of Technology · Center for Imaging Science, Rochester Institute of Technology