Genetic Algorithms in Neural Architecture Search

#genetic algorithms #neural architecture search #evolutionary optimization #deep learning #machine learning #optimization algorithms #fitness functions #search spaces #performance metrics #encoding architectures

1. Core Principles of Genetic Algorithms

Core Principles of Genetic Algorithms

Population-Based Stochastic Search

Genetic algorithms (GAs) operate on a population of candidate solutions, encoded as chromosomes, rather than a single point in the search space. Each chromosome represents a potential solution to the optimization problem, typically as a binary string, real-valued vector, or graph structure. The population evolves over generations through biologically inspired operators: selection, crossover, and mutation. This parallel exploration of the search space enables GAs to avoid local optima more effectively than gradient-based methods.

Fitness-Based Selection

The fitness function quantifies solution quality, driving the evolutionary process. Selection mechanisms favor high-fitness individuals for reproduction while maintaining diversity. Common selection methods include:

$$ P_i = \frac{f_i}{\sum_{j=1}^{N} f_j} $$

where \( P_i \) is the selection probability of individual \( i \), \( f_i \) its fitness, and \( N \) the population size.

Crossover and Mutation Operators

Crossover recombines genetic material from parent chromosomes to produce offspring. For binary representations, single-point crossover swaps segments:

$$ \begin{align*} \text{Parent A:} & \quad 1101|0010 \\ \text{Parent B:} & \quad 1010|1101 \\ \text{Offspring:} & \quad 1101\underline{1101} \end{align*} $$

Mutation introduces random perturbations with low probability (typically 0.1-1%), maintaining genetic diversity. For binary encoding, bit-flip mutation inverts randomly selected bits.

Convergence and Elitism

Premature convergence occurs when the population loses diversity too rapidly. Elitism preserves top-performing individuals unchanged across generations, guaranteeing monotonic improvement in the best solution. The convergence rate depends on:

Neural Architecture Search Applications

In neural architecture search (NAS), chromosomes encode network topologies (e.g., layer types, connectivity patterns). Fitness evaluation involves training candidate architectures and measuring validation accuracy. Recent advancements combine GAs with gradient-based optimization for hybrid efficiency.

$$ \text{Fitness} = \text{Accuracy} - \lambda \cdot \text{FLOPs} $$

where \( \lambda \) controls the computational cost trade-off.

Core Principles of Genetic Algorithms – Genetic Algorithms in Neural Architecture Search – Tutorial Diagram
Diagram Description: The diagram would show the evolutionary process of genetic algorithms, including population initialization, selection, crossover, and mutation operations.

Key Components: Selection, Crossover, and Mutation

Selection Mechanisms in Neural Architecture Search

Selection operators determine which candidate architectures proceed to the next generation based on fitness scores. In neural architecture search (NAS), fitness typically represents validation accuracy or a multi-objective combination of accuracy and computational efficiency. Tournament selection and roulette wheel selection are most commonly employed:

$$ P_i = \frac{f_i}{\sum_{j=1}^N f_j} $$

where Pi is the selection probability for architecture i, and fi is its fitness. For tournament selection, k architectures are randomly sampled, and the highest-fitness candidate is selected. This provides explicit control over selection pressure through the tournament size parameter.

Crossover Operations for Architecture Graphs

Crossover combines topological features from parent architectures to produce offspring. In NAS, this requires specialized graph-based crossover operators:

The crossover probability pc typically ranges between 0.6-0.9 in practice. Recent work by Real et al. (2019) demonstrated that weight inheritance during crossover can accelerate convergence by up to 3× compared to random reinitialization.

Mutation Operators for Neural Topologies

Mutation introduces architectural innovations through local modifications. Common NAS mutation operators include:

$$ \begin{aligned} &\text{Add layer: } & p_{\text{add}} &= 0.2 \\ &\text{Remove layer: } & p_{\text{remove}} &= 0.2 \\ &\text{Alter hyperparameters: } & p_{\text{alter}} &= 0.6 \end{aligned} $$

Each mutation type requires domain-specific constraints. For example, adding a layer must preserve dimensional compatibility, while altering convolution kernels must maintain valid padding configurations. Adaptive mutation rates that decrease during evolution often outperform fixed probabilities.

Practical Implementation Considerations

When implementing these operators for NAS:

The computational complexity of crossover and mutation operations scales with the size of the architecture search space. For large spaces, approximate validity checks may be necessary to maintain reasonable generation times.

Key Components: Selection, Crossover, and Mutation – Genetic Algorithms in Neural Architecture Search – Tutorial Diagram
Diagram Description: The diagram would show the graph-based crossover operations between two neural architectures, illustrating layer-wise and subgraph exchanges with connectivity preservation.

Fitness Functions and Evolutionary Optimization

Designing Effective Fitness Functions

The fitness function in genetic algorithms for neural architecture search (NAS) serves as the objective criterion that evaluates the performance of candidate architectures. Unlike traditional optimization problems, NAS requires multi-objective trade-offs between accuracy, computational efficiency, and model complexity. A well-designed fitness function F typically takes the form:

$$ F(\theta) = \alpha \cdot \text{Accuracy}(\theta) + \beta \cdot \text{Efficiency}(\theta) + \gamma \cdot \text{Complexity}(\theta) $$

where θ represents the neural architecture parameters, and α, β, γ are weighting coefficients that balance competing objectives. The accuracy term is usually measured via validation performance, while efficiency can be quantified through FLOPs or latency measurements. Complexity often uses parameter count or topological measures.

Evolutionary Optimization Mechanics

Evolutionary optimization in NAS operates through selection, crossover, and mutation operators acting on a population of neural architectures. The selection pressure is directly governed by the fitness function through mechanisms like tournament selection:

$$ P_{\text{select}}(A_i) = \frac{F(A_i)}{\sum_{j=1}^N F(A_j)} $$

where Ai denotes an architecture in the population of size N. This probabilistic selection drives the population toward higher-fitness regions of the search space.

Pareto Optimization for Multi-Objective NAS

When conflicting objectives cannot be collapsed into a scalar fitness value, Pareto optimization maintains a frontier of non-dominated solutions. An architecture A1 dominates A2 iff:

$$ \forall i \in \text{objectives}: f_i(A_1) \geq f_i(A_2) \land \exists j: f_j(A_1) > f_j(A_2) $$

This approach has proven particularly effective in hardware-aware NAS, where accuracy-latency or accuracy-energy trade-offs are essential.

Practical Considerations and Challenges

Fitness evaluation constitutes the computational bottleneck in evolutionary NAS, as each candidate architecture typically requires training and validation. Strategies to address this include:

The noise inherent in fitness evaluations (from random initialization and mini-batch sampling) necessitates robust selection mechanisms. Techniques like fitness averaging over multiple trials or uncertainty-aware selection have shown promise in noisy evolutionary environments.

Advanced Evolutionary Operators

Modern evolutionary NAS systems employ specialized variation operators that respect neural network constraints:

These operators must balance exploration of novel architectures with exploitation of known high-performing building blocks, often guided by the fitness landscape's characteristics.

Fitness Functions and Evolutionary Optimization – Genetic Algorithms in Neural Architecture Search – Tutorial Diagram
Diagram Description: The section involves multi-objective trade-offs in fitness functions and evolutionary operators, which would benefit from a visual representation of the Pareto frontier and genetic operations.

2. Overview of NAS and Its Challenges

Overview of NAS and Its Challenges

Neural Architecture Search (NAS) automates the design of artificial neural networks, aiming to discover architectures that achieve optimal performance for a given task. Traditional NAS methods rely on reinforcement learning, gradient-based optimization, or evolutionary algorithms, with genetic algorithms (GAs) emerging as a powerful approach due to their ability to explore vast and complex search spaces efficiently.

Search Space Definition

The search space in NAS defines the set of possible architectures that can be explored. Common representations include:

The choice of search space significantly impacts the efficiency and effectiveness of NAS. A poorly defined search space may lead to suboptimal architectures or excessive computational costs.

Challenges in NAS

Despite its promise, NAS faces several critical challenges:

Genetic Algorithms in NAS

Genetic algorithms provide a robust framework for NAS by mimicking natural selection:

$$ f(\theta) = \mathbb{E}_{(x,y) \sim \mathcal{D}}[\mathcal{L}(y, \text{NN}(x; \theta))] $$

where θ represents the architecture parameters, 𝒟 is the dataset, and is the loss function. GAs optimize this objective through:

This iterative process continues until convergence or a predefined computational budget is exhausted.

Practical Considerations

Implementing GA-based NAS requires careful attention to:

Recent advances, such as multi-objective optimization (balancing accuracy, latency, and energy consumption), further enhance the practicality of GA-based NAS in real-world applications.

Overview of NAS and Its Challenges – Genetic Algorithms in Neural Architecture Search – Tutorial Diagram
Diagram Description: The diagram would show the genetic algorithm workflow in NAS, including population initialization, fitness evaluation, selection, crossover, and mutation stages.

Search Spaces in NAS: Layer Types and Connectivity

The search space defines the set of possible neural architectures that a genetic algorithm can explore during Neural Architecture Search (NAS). A well-designed search space balances expressiveness and tractability, enabling the discovery of high-performing architectures without excessive computational overhead. Two primary components govern the search space: layer types and connectivity patterns.

Layer Types

Modern NAS search spaces incorporate a diverse set of layer operations, each contributing unique inductive biases. Common layer types include:

The probability of selecting a layer type can be encoded in the genetic algorithm's chromosome. For example, a discrete gene with values {0,1,2,3} might map to {conv3×3, conv5×5, depthwise-separable, max-pool} respectively.

Connectivity Patterns

Connectivity defines how layers are wired together, significantly impacting gradient flow and representational capacity. Key approaches include:

For DAG-based search spaces, the genetic representation must encode both node operations and edges. A common approach uses an upper triangular adjacency matrix E where Eij = 1 indicates a connection from node i to node j:

$$ E = \begin{bmatrix} 0 & e_{12} & \cdots & e_{1n} \\ 0 & 0 & \ddots & \vdots \\ \vdots & \vdots & \ddots & e_{(n-1)n} \\ 0 & 0 & \cdots & 0 \end{bmatrix} $$

Search Space Constraints

Practical search spaces incorporate constraints to maintain feasibility:

These constraints can be implemented either as hard limits during genome decoding or as soft penalties in the fitness evaluation. The latter approach often proves more flexible for evolutionary methods.

Real-World Implementation

In practice, search spaces are often implemented as weighted supernetworks where:

$$ \mathcal{A} = \bigcup_{i=1}^{k} \alpha_i \mathcal{O}_i $$

where 𝒪i represents candidate operations and αi are architectural weights optimized jointly with network parameters. Genetic algorithms manipulate the discrete selection variables αi ∈ {0,1} while gradient-based methods relax these to continuous values.

Search Spaces in NAS: Layer Types and Connectivity – Genetic Algorithms in Neural Architecture Search – Tutorial Diagram
Diagram Description: The section describes complex connectivity patterns (DAGs, adjacency matrices) and cell-based architectures that are inherently spatial and visual.

Performance Metrics for Evaluating Architectures

Accuracy and Generalization

The most fundamental metric for evaluating neural architectures is classification accuracy on a held-out validation set. For a model with predictions ŷ and true labels y, accuracy is computed as:

$$ \text{Accuracy} = \frac{1}{N} \sum_{i=1}^N \mathbb{I}(\hat{y}_i = y_i) $$

However, raw accuracy alone can be misleading due to overfitting. The generalization gap—the difference between training and validation accuracy—provides critical insight into an architecture's ability to learn meaningful patterns rather than memorizing data. Architectures with generalization gaps exceeding 15-20% typically require regularization or simplification.

Computational Efficiency Metrics

In production systems, computational constraints are often as important as accuracy. Three key metrics quantify efficiency:

  • FLOPs (Floating Point Operations): Total multiply-add operations during inference
  • Latency: Wall-clock time per prediction on target hardware
  • Memory Footprint: Peak memory consumption during inference

For convolutional layers, FLOPs can be derived from layer dimensions:

$$ \text{FLOPs} = 2 \times H \times W \times C_{in} \times C_{out} \times K_h \times K_w $$

where H,W are spatial dimensions, C are channel counts, and K is kernel size.

Multi-Objective Pareto Efficiency

When optimizing both accuracy and efficiency, architectures lie on a Pareto frontier—a curve where improving one metric necessitates degrading another. The hypervolume indicator quantifies this trade-off:

$$ HV = \text{Volume}\left( \bigcup_{a \in A} [a_1, r_1] \times \cdots \times [a_d, r_d] \right) $$

where A is the set of architectures, d is the number of objectives, and r is a reference point dominated by all solutions. Genetic algorithms often use this metric to maintain diverse populations.

Robustness Metrics

Modern architectures must maintain performance under distribution shifts. Key robustness metrics include:

  • Adversarial Accuracy: Classification accuracy under PGD attacks
  • Corruption Error: Performance drop on artificially corrupted data (e.g., ImageNet-C)
  • Effective Robustness: The difference between actual and expected robustness given clean accuracy

For adversarial robustness, the ℓ₂ distortion threshold provides a scalar metric:

$$ \tau = \min_{\delta} ||\delta||_2 \quad \text{s.t.} \quad f(x+\delta) \neq f(x) $$

Architecture Ranking Consistency

When evaluating architectures across multiple seeds or datasets, Kendall's Tau coefficient measures ranking consistency:

$$ \tau = \frac{2}{n(n-1)} \sum_{i

where r and s are rankings from different evaluation runs. Values below 0.7 indicate high variance in architecture performance.

Performance Metrics for Evaluating Architectures – Genetic Algorithms in Neural Architecture Search – Tutorial Diagram
Diagram Description: The Pareto frontier concept is inherently visual, showing the trade-off between accuracy and computational efficiency metrics.

3. Encoding Neural Architectures for Genetic Representation

3.1 Encoding Neural Architectures for Genetic Representation

The effectiveness of genetic algorithms (GAs) in neural architecture search (NAS) hinges on the choice of encoding scheme, which determines how neural network topologies are represented as chromosomes. A well-designed encoding must balance expressiveness, compactness, and evolvability while preserving the feasibility of decoded architectures.

Direct Encoding Schemes

Direct encoding explicitly defines each component of the neural network, including layer types, connectivity patterns, and hyperparameters. A common approach represents the architecture as a fixed-length string where each gene corresponds to a specific architectural feature. For example, in a feedforward network:

$$ C = [l_1, l_2, ..., l_n, w_{1,2}, w_{2,3}, ..., w_{n-1,n}] $$

where li encodes layer type (e.g., 0=convolutional, 1=recurrent) and wi,j specifies connectivity between layers. While straightforward, this method suffers from combinatorial explosion in deep networks and produces many invalid offspring during crossover.

Graph-Based Encodings

Modern approaches often employ graph representations where nodes denote operations (convolution, pooling) and edges represent data flow. The adjacency matrix A and feature matrix F provide a natural encoding:

$$ A \in \{0,1\}^{n \times n}, \quad F \in \mathbb{R}^{n \times d} $$

where n is the maximum node count and d encodes operation types. This allows evolutionary operators to modify both connectivity (through A) and operations (through F). The NEAT algorithm pioneered this approach with historical markings to track gene lineage.

Variable-Length Encodings

For architectures with varying depth, grammatical evolution encodes networks using production rules from a context-free grammar. Each chromosome is a sequence of integers that guides rule selection during derivation:

$$ S \rightarrow \text{Conv}(k) \mid \text{Pool}(t) \mid S \circ S $$

where k represents kernel size, t pooling type, and denotes composition. This enables meaningful crossover while maintaining syntactic validity, though search efficiency depends heavily on grammar design.

Performance-Aware Embeddings

Recent work incorporates learned embeddings that map architectures to latent spaces where geometric distance correlates with performance difference. The encoding function fθ projects discrete architectures to continuous vectors:

$$ f_\theta: \mathcal{A} \rightarrow \mathbb{R}^k $$

optimized such that ||fθ(ai) - fθ(aj)|| ≈ |acc(ai) - acc(aj)|. Evolutionary operators then act in this smoothed space before decoding.

Practical implementations often combine these approaches—using graph encodings for macro-architecture while employing grammatical evolution for cell-level structures, as seen in Hierarchical NAS. The choice fundamentally constrains the search space topology and consequently impacts optimization dynamics.

Encoding Neural Architectures for Genetic Representation – Genetic Algorithms in Neural Architecture Search – Tutorial Diagram
Diagram Description: The diagram would show a side-by-side comparison of different encoding schemes (direct, graph-based, grammatical) with concrete examples of neural architectures represented in each format.

3.2 Designing Effective Fitness Functions for NAS

The fitness function in genetic algorithm-based Neural Architecture Search (NAS) serves as the primary mechanism for evaluating and ranking candidate architectures. Unlike traditional optimization problems, NAS requires multi-objective fitness functions that balance accuracy, computational efficiency, and other domain-specific constraints.

Key Components of NAS Fitness Functions

An effective fitness function for NAS typically incorporates three primary components:

  • Model Performance: Measured through validation accuracy, F1-score, or task-specific metrics
  • Computational Cost: Including FLOPs, parameter count, or latency measurements
  • Architectural Constraints: Such as maximum depth, branching factor, or hardware compatibility

The challenge lies in formulating these competing objectives into a single scalar value that guides the evolutionary process effectively. Common approaches include weighted linear combinations and Pareto frontier optimization.

Mathematical Formulation

The most prevalent formulation uses a weighted sum approach:

$$ \mathcal{F}(\alpha) = w_1 \cdot \text{Perf}(\alpha) - w_2 \cdot \text{Cost}(\alpha) - w_3 \cdot \text{Penalty}(\alpha) $$

Where:

  • $$\alpha$$ represents the neural architecture
  • $$\text{Perf}(\alpha)$$ is the normalized performance metric
  • $$\text{Cost}(\alpha)$$ captures computational requirements
  • $$\text{Penalty}(\alpha)$$ enforces architectural constraints

Adaptive Weighting Strategies

Static weights often lead to suboptimal exploration. Advanced implementations use adaptive weighting:

$$ w_i^{(t+1)} = w_i^{(t)} + \eta \frac{\partial \mathcal{L}}{\partial w_i} $$

Where $$\eta$$ is a learning rate and $$\mathcal{L}$$ represents the meta-loss function measuring search progress. This allows the algorithm to dynamically adjust its exploration-exploitation balance.

Pareto Optimization Approaches

For truly multi-objective optimization, Pareto-efficient solutions can be maintained using non-dominated sorting:

  1. Calculate dominance relationships between all architectures
  2. Assign Pareto ranks to each solution
  3. Use crowding distance to maintain diversity

The fitness assignment becomes:

$$ \mathcal{F}(\alpha) = \text{rank}(\alpha) + \frac{1}{\text{crowding}(\alpha) + \epsilon} $$

Practical Considerations

Real-world implementations must account for:

  • Noisy evaluations: Performance metrics vary across training runs
  • Partial evaluations: Early stopping to accelerate search
  • Transfer learning: Leveraging knowledge from previous searches

Recent work in progressive neural architecture search demonstrates that dynamically adjusting the fidelity of evaluations throughout the search process can significantly improve efficiency without compromising result quality.

Case Study: MobileNetV3 Search

The MobileNetV3 architecture search employed a compound fitness function:

$$ \mathcal{F}(\alpha) = \text{Accuracy}(\alpha) \cdot \left[\frac{\text{Latency}(\alpha)}{T}\right]^{w(t)} $$

Where $$T$$ was the target latency and $$w(t)$$ decreased linearly throughout the search to initially favor exploration then gradually emphasize constraint satisfaction.

Designing Effective Fitness Functions for NAS – Genetic Algorithms in Neural Architecture Search – Tutorial Diagram
Diagram Description: The diagram would show the multi-objective trade-offs in NAS fitness functions, visually representing how performance, cost, and constraints interact in the weighted sum and Pareto optimization approaches.

3.3 Optimizing Search Efficiency with Genetic Operators

Genetic operators—selection, crossover, and mutation—are the core mechanisms driving the evolution of neural architectures in Genetic Algorithm-based Neural Architecture Search (GA-NAS). Their design critically impacts the trade-off between exploration (diversifying the search space) and exploitation (refining high-performing candidates).

Selection Strategies for Architecture Preservation

Fitness-proportionate selection methods like roulette wheel selection introduce stochasticity but may prematurely converge on suboptimal architectures. Tournament selection, where k architectures compete based on validation accuracy, provides stronger pressure toward high-performance candidates. For NAS, the tournament size k follows:

$$ P_{\text{select}} = 1 - (1 - p)^k $$

where p is the probability of selecting a better architecture. A dynamic k that increases with generations balances early exploration and late-stage refinement.

Crossover Operators for Modular Composition

Single-point crossover often disrupts functional neural modules. Instead, block-level crossover exchanges entire residual blocks or attention mechanisms between parent architectures. Given two parent architectures A and B with L layers, the crossover point l is sampled from:

$$ l \sim \text{Categorical}(\theta), \quad \theta_l = \frac{\text{FLOPs}(A_{1:l}) + \text{FLOPs}(B_{1:l})}{\text{FLOPs}(A) + \text{FLOPs}(B)} $$

This biases crossover toward regions of comparable computational cost, preserving functional integrity.

Mutation with Architectural Constraints

Gaussian noise on continuous parameters (e.g., learning rates) is insufficient for NAS. Discrete mutations must respect neural network validity constraints:

  • Layer insertion/deletion: Probability inversely proportional to current depth deviation from target
  • Operation change: Weighted by hardware latency estimates for the target device
  • Skip connection addition: Favored when gradient flow metrics indicate vanishing gradients

The mutation rate μ typically follows an exponential decay schedule:

$$ \mu_t = \mu_0 \cdot e^{-\lambda t} $$

where λ controls the exploration-to-exploitation transition speed.

Pareto-optimal Operator Adaptation

Multi-objective optimization requires operator adaptation to the Pareto front. NSGA-II's crowding distance metric can guide operator selection:

$$ d_i = \sum_{m=1}^M \frac{f_m(i+1) - f_m(i-1)}{f_m^{\max} - f_m^{\min}} $$

where fm are normalized objectives (accuracy, latency, etc.). Operators are then applied with probabilities proportional to candidates' crowding distances.

Parallelization Through Island Models

Geographically separated subpopulations (islands) with distinct operator configurations accelerate search. Migration intervals follow:

$$ \tau = \left\lfloor \frac{\log(1 - \alpha)}{\log(1 - \frac{1}{N})} \right\rfloor $$

where α is the desired probability of migration occurring and N is the island count. This prevents premature synchronization while maintaining diversity.

Optimizing Search Efficiency with Genetic Operators – Genetic Algorithms in Neural Architecture Search – Tutorial Diagram
Diagram Description: The section describes complex genetic operators (crossover, mutation) and their impact on neural architectures, which inherently involve spatial and structural relationships.

4. Step-by-Step Implementation of GA-NAS

Step-by-Step Implementation of GA-NAS

1. Problem Encoding

Genetic Algorithms (GAs) require a suitable encoding scheme to represent neural architectures as chromosomes. For Neural Architecture Search (NAS), the most common approach is a direct encoding where each gene corresponds to a specific architectural hyperparameter (e.g., layer type, kernel size, number of filters). Alternatively, indirect encoding compresses the architecture into a lower-dimensional representation, reducing search space complexity.

$$ \text{Chromosome} = [g_1, g_2, ..., g_n], \quad g_i \in \{0,1\}^k \text{ or } \mathbb{R} $$

For example, a convolutional layer can be encoded as a tuple (type, kernel_size, stride, filters), while a recurrent layer may use (type, units, activation). The choice of encoding impacts the GA's ability to explore the search space efficiently.

2. Initial Population Generation

The initial population is typically generated randomly, but domain knowledge can guide sampling to avoid obviously poor architectures. For a population size N, each individual is constructed by:

  • Sampling layer types (convolutional, pooling, dense) from a predefined set.
  • Selecting hyperparameters (e.g., kernel sizes ∈ {3,5,7}, filters ∈ [16, 256]).
  • Ensuring valid connectivity (e.g., no incompatible layer sequences).

3. Fitness Evaluation

Each architecture’s fitness is evaluated by training it on a subset of data and measuring validation accuracy or a custom metric like FLOPs-accuracy trade-off. To reduce computational cost:

  • Use weight sharing (e.g., ENAS) or proxy tasks (shorter training epochs).
  • Leverage surrogate models to predict performance without full training.
$$ \text{Fitness} = \alpha \cdot \text{Accuracy} - \beta \cdot \text{FLOPs} + \gamma \cdot \text{Params} $$

4. Selection, Crossover, and Mutation

Tournament or roulette-wheel selection identifies high-fitness individuals for reproduction. Crossover combines parent chromosomes to create offspring, while mutation introduces random perturbations:

  • Single-point crossover: Swaps subsequences of layer configurations between parents.
  • Gaussian mutation: Adds noise to continuous hyperparameters (e.g., learning rate).
  • Swap mutation: Exchanges two randomly selected genes in the chromosome.

5. Termination and Elitism

The algorithm terminates after K generations or when fitness plateaus. Elitism preserves the top M architectures unchanged in the next generation to avoid losing high-performing candidates.

Practical Example: Implementing GA-NAS with Python

Below is a simplified GA-NAS implementation using PyTorch and DEAP (Distributed Evolutionary Algorithms in Python):


import random
from deap import base, creator, tools

# Define fitness and individual classes
creator.create("FitnessMax", base.Fitness, weights=(1.0,))
creator.create("Individual", list, fitness=creator.FitnessMax)

toolbox = base.Toolbox()
toolbox.register("attr_layer", random.choice, ["conv", "pool", "dense"])
toolbox.register("attr_filters", random.randint, 16, 256)
toolbox.register("individual", tools.initCycle, creator.Individual,
                 (toolbox.attr_layer, toolbox.attr_filters), n=1)
toolbox.register("population", tools.initRepeat, list, toolbox.individual)

def evaluate(individual):
   # Train and validate the architecture
   accuracy = train_model(individual)
   return (accuracy,)

toolbox.register("evaluate", evaluate)
toolbox.register("mate", tools.cxTwoPoint)
toolbox.register("mutate", tools.mutGaussian, mu=0, sigma=1, indpb=0.2)
toolbox.register("select", tools.selTournament, tournsize=3)

# Run evolution
population = toolbox.population(n=50)
for gen in range(10):
   offspring = algorithms.varAnd(population, toolbox, cxpb=0.5, mutpb=0.1)
   fits = toolbox.map(toolbox.evaluate, offspring)
   for fit, ind in zip(fits, offspring):
      ind.fitness.values = fit
   population = toolbox.select(offspring, k=len(population))
   

Optimization Challenges

Key challenges include balancing exploration-exploitation trade-offs and computational costs. Techniques like adaptive mutation rates or parallel evaluation (e.g., using Ray or Dask) can mitigate these issues. Recent work also integrates GAs with gradient-based methods (e.g., DARTS) for hybrid optimization.

Step-by-Step Implementation of GA-NAS – Genetic Algorithms in Neural Architecture Search – Tutorial Diagram
Diagram Description: A diagram would show the chromosome encoding structure and how crossover/mutation operations physically alter the architecture representation.

4.2 Benchmarking GA-NAS Against Other NAS Methods

Genetic Algorithm-based Neural Architecture Search (GA-NAS) competes with alternative NAS approaches across computational efficiency, search space flexibility, and final model performance. Quantitative comparisons typically evaluate Pareto-optimal trade-offs between accuracy, parameters, and FLOPs across benchmark datasets like CIFAR-10/100 or ImageNet.

Performance Metrics

The dominant evaluation framework measures:

  • Test Accuracy (Top-1/Top-5): Predictive performance on held-out data
  • Search Cost: GPU days or floating-point operations (FLOPs) required
  • Model Complexity: Parameter count and memory footprint
$$ \text{Search Efficiency} = \frac{\text{Test Accuracy}}{\log(\text{Search Cost})} $$

Comparative Analysis

Against reinforcement learning-based NAS (e.g., NASNet, ENAS), GA-NAS demonstrates:

  • 30-50% lower search costs due to parallelizable population evaluations
  • Comparable accuracy (±1.2%) on image classification tasks
  • Superior performance on constrained search spaces (<1015 architectures)

When benchmarked against gradient-based methods (e.g., DARTS):

  • GA-NAS achieves better topology diversity with 2.3× more unique cell patterns
  • 5-8% higher robustness to adversarial attacks on CIFAR-10
  • Higher variance in final performance (σ=0.7%) due to stochastic selection

Computational Trade-offs

The time complexity of GA-NAS scales as:

$$ O(g \cdot p \cdot f) $$

where g is generations, p is population size, and f is fitness evaluation cost. This contrasts with RL-NAS's O(n2) sampling complexity and DARTS's O(k3) memory overhead for k operations.

Case Study: ImageNet Classification

Recent experiments on ImageNet-1K reveal:

Method Top-1 Acc. Params (M) Search Cost (GPU-days)
GA-NAS (AmoebaNet) 83.9% 5.1 3,150
RL-NAS (NASNet-A) 82.7% 5.3 4,800
GD-NAS (DARTS) 83.1% 4.9 1.5

While gradient-based methods achieve faster search, GA-NAS maintains advantages in hardware-aware optimization - producing architectures with 15-20% lower latency on TPUv3 accelerators due to more regular computation patterns.

4.3 Real-World Applications and Performance Insights

Optimizing Deep Neural Networks with Genetic Algorithms

Genetic algorithms (GAs) have demonstrated remarkable success in automating neural architecture search (NAS) for complex deep learning models. In practice, GAs optimize architectures by treating hyperparameters (e.g., layer depth, filter sizes, activation functions) as genes in a chromosome. The fitness function evaluates model performance on validation data, guiding selection, crossover, and mutation operations. For instance, Google's AmoebaNet achieved state-of-the-art accuracy on ImageNet by evolving architectures through tournament selection and asynchronous updates.

$$ \text{Fitness}(A) = \alpha \cdot \text{Accuracy}(A) - \beta \cdot \text{FLOPs}(A) $$

Here, A represents a candidate architecture, while α and β balance accuracy and computational efficiency.

Case Study: Evolutionary NAS in Medical Imaging

Researchers at Stanford applied GA-driven NAS to optimize convolutional neural networks (CNNs) for detecting pulmonary nodules in CT scans. The algorithm explored architectures with varying kernel sizes (3×3 to 7×7), skip connections, and pooling strategies. The evolved model reduced false positives by 18% compared to manually designed CNNs while maintaining 94.3% sensitivity. Key observations:

  • Mutation rate above 0.2 caused instability in convergence.
  • Elitism preservation (retaining top 10% performers) accelerated search by 3.2×.
  • The Pareto front revealed a trade-off between inference speed (<300ms) and AUC-ROC (>0.91).

Computational Efficiency and Parallelization

Distributed GA-NAS frameworks leverage GPU clusters to evaluate hundreds of architectures simultaneously. Facebook's DeepEvolution employs a master-worker paradigm where:

  • The master node manages population selection and genetic operations.
  • Workers asynchronously train and evaluate candidate models.

This approach reduced search time for a ResNet-50 variant from 2,000 GPU hours to 450 hours while improving ImageNet top-1 accuracy by 1.4%.

Performance Comparison: GA vs. Reinforcement Learning (RL) in NAS

Metric Genetic Algorithm RL-Based NAS
Search Time (GPU hours) 450–800 1,200–2,500
Architecture Diversity High (30–50 unique variants) Low (5–10 dominant paths)
Final Model Accuracy ±0.5% of SOTA ±0.3% of SOTA

Challenges and Mitigation Strategies

While GA-NAS shows promise, practitioners face several hurdles:

  • Search Space Design: Overly constrained spaces limit discovery. Solution: Hierarchical gene representation allowing macro/micro architecture mutations.
  • Evaluation Bottlenecks: Fitness computation dominates runtime. Solution: Surrogate models (e.g., Gaussian processes) predict performance from partial training.
  • Multi-Objective Optimization: Balancing accuracy, latency, and energy use requires advanced selection criteria like NSGA-II.
$$ \text{NSGA-II Ranking} = \sum_{i=1}^{k} w_i \cdot \text{Normalize}(f_i(A)) $$

Where wi are user-defined weights for objectives f1 to fk.

5. Scalability and Computational Costs

5.1 Scalability and Computational Costs

Genetic algorithms (GAs) in neural architecture search (NAS) face significant scalability challenges due to the combinatorial explosion of possible architectures. The search space grows exponentially with the number of layers, operations, and hyperparameters, making exhaustive evaluation computationally intractable. For a network with L layers and O possible operations per layer, the total search space size is:

$$ |\mathcal{S}| = O^L $$

For example, a ResNet-like search space with L=20 and O=8 yields 820 ≈ 1.15×1018 possible architectures. Evaluating each architecture through full training would require prohibitive computational resources.

Computational Bottlenecks

The primary costs in GA-based NAS arise from three components:

  • Fitness evaluation: Each candidate architecture requires training and validation, often consuming hundreds of GPU-hours per individual.
  • Population management: Maintaining large populations (typically 50-500 individuals) multiplies the evaluation cost.
  • Generational turnover: Convergence often requires 50-100 generations, compounding the total cost.

Scalability Techniques

1. Surrogate Models

Low-fidelity proxies predict architecture performance without full training:

$$ \hat{f}(a) \approx f(a) $$

where f(a) is the true validation accuracy and hat{f}(a) is the surrogate prediction. Common approaches include:

  • Hypernetworks that predict weights
  • Performance predictors based on architecture embeddings
  • Early stopping after partial training

2. Evolutionary Operators

Efficient mutation and crossover strategies reduce wasted evaluations:

  • Parameterized mutations: Learn probability distributions over operations
  • Directed crossover: Favor recombination of high-performing building blocks
  • Age-Layering: Implement generational hierarchies to preserve diversity

3. Distributed Evaluation

Parallelization strategies include:

  • Asynchronous evolution: Update population continuously as evaluations complete
  • Island models: Maintain subpopulations with periodic migration
  • Federated evaluation: Distribute fitness computation across multiple nodes

Computational Complexity Analysis

The total cost C for a GA with population size P running G generations is:

$$ C = P \times G \times T_{eval} $$

where Teval is the average evaluation time. With surrogate models, this becomes:

$$ C = P \times G \times (T_{surrogate} + \alpha T_{eval}) $$

where α is the fraction of architectures selected for full evaluation. State-of-the-art methods achieve α < 0.1 while maintaining search quality.

Case Study: Large-Scale NAS

In the DARTS-2 architecture search, researchers reduced computational costs by:

  • Using a learned performance predictor (3% error vs. full training)
  • Implementing asynchronous evaluation across 200 TPUv2 cores
  • Applying progressive population sizing (starting with P=50, growing to P=200)

This approach discovered competitive architectures with just 12 GPU-days compared to the original DARTS' 96 GPU-days, demonstrating effective scaling techniques.

Scalability and Computational Costs – Genetic Algorithms in Neural Architecture Search – Tutorial Diagram
Diagram Description: The diagram would show the exponential growth of the search space with increasing layers and operations, and contrast it with computational cost reduction techniques like surrogate models and distributed evaluation.

5.2 Overcoming Local Optima in GA-NAS

Local optima pose a significant challenge in Genetic Algorithm-based Neural Architecture Search (GA-NAS), where the search process converges to suboptimal architectures due to premature exploitation of seemingly high-performing candidates. This stagnation arises from the loss of genetic diversity, causing the population to homogenize around architectures that perform well on initial evaluations but fail to generalize or scale.

Fitness Landscape Analysis

The fitness landscape in GA-NAS is often rugged, with many local optima separated by low-fitness regions. The probability of convergence to a local optimum increases when selection pressure favors immediate performance over exploration. Mathematically, this can be modeled by analyzing the basin of attraction around local optima:

$$ \mathcal{B}(A_i) = \{ A_j \in \mathcal{P} \,|\, \mathbb{E}[f(A_j)] \rightarrow f(A_i) \text{ under selection} \} $$

where Ai is a local optimum architecture, P is the population, and f is the fitness function.

Diversity-Preserving Mechanisms

Several techniques counteract premature convergence:

  • Fitness Sharing: Penalizes the fitness of similar architectures to prevent overcrowding in genotype space. The shared fitness f' is computed as:
$$ f'(A_i) = \frac{f(A_i)}{\sum_{j=1}^N sh(d(A_i, A_j))} $$

where sh(d) is a sharing function (e.g., triangular or power-law) based on distance metric d between architectures.

  • Crowding and Niching: Replaces similar parents with offspring to maintain subpopulations in distinct niches. Deterministic crowding uses:
$$ p_{\text{replace}} = \frac{f(A_{\text{offspring}})}{f(A_{\text{parent}}) + f(A_{\text{offspring}})} $$

Adaptive Mutation Strategies

Dynamic mutation rates help escape local optima by periodically introducing large perturbations:

$$ p_m(t) = p_{m0} \cdot e^{-\lambda t} + p_{m,\min} $$

where pm0 is the initial mutation rate, λ controls decay, and pm,min ensures minimal exploration. Alternatively, novelty search replaces fitness objectives with behavioral diversity metrics, rewarding architectures that differ from existing solutions.

Island Models and Parallel Exploration

Multi-population approaches (island models) run independent GA instances with periodic migration. This creates meta-diversity, as islands may converge to different optima. The migration policy often follows:

$$ \mathcal{M}_{i \rightarrow j} = \begin{cases} \frac{f(A_i) - \mu_j}{\sigma_j} > \theta & \text{elitist migration} \\ \text{Probabilistic} & \text{uniform mixing} \end{cases} $$

where μj and σj are the mean and standard deviation of fitness in island j.

Hybridization with Local Search

Combining GA with local search (e.g., Lamarckian evolution or memetic algorithms) allows fine-tuning promising architectures. For instance, gradient-based architecture optimization can be applied to elite candidates before reintroduction to the population.

Comparison of standard GA vs diversity-preserving GA in NAS Generation Fitness Standard GA Diversity-Preserving GA
Overcoming Local Optima in GA-NAS – Genetic Algorithms in Neural Architecture Search – Tutorial Diagram
Diagram Description: The section includes a comparison of fitness progression between standard GA and diversity-preserving GA, which is inherently visual and best represented graphically.

5.3 Emerging Trends and Hybrid Approaches

Neuroevolution with Gradient-Based Fine-Tuning

Recent work has demonstrated that combining genetic algorithms (GAs) with gradient-based optimization can yield architectures that outperform purely evolutionary or purely gradient-based approaches. The hybrid pipeline typically follows:

  1. A GA generates candidate architectures.
  2. Promising candidates undergo short-term gradient-based training (e.g., 1-5 epochs).
  3. The validation performance guides the selection and mutation of architectures.
$$ \mathcal{L}_{hybrid} = \alpha \mathcal{L}_{evo} + (1-\alpha)\mathcal{L}_{grad} $$

where α balances exploration (evolutionary) and exploitation (gradient) terms. Empirical studies suggest α ≈ 0.7 works well for convolutional networks.

Multi-Objective Optimization in NAS

Traditional NAS often optimizes for accuracy alone, but real-world deployments require balancing:

  • Computational complexity (FLOPs, latency)
  • Memory footprint (parameter count, activation size)
  • Robustness (adversarial resilience, noise tolerance)

The Pareto front emerges as a key concept, with NSGA-II being a popular choice for multi-objective GA-NAS. The fitness function extends to:

$$ F(\theta) = \sum_{i=1}^k w_i f_i(\theta), \quad \sum w_i = 1 $$

Efficient Encoding Schemes

Recent advances in architecture representation include:

  • Graph-based encodings: Represent networks as directed acyclic graphs with learnable edge probabilities.
  • Differentiable relaxations: Use continuous relaxations of discrete architecture choices during search.
  • Hierarchical representations: Decompose macro and micro-architecture searches.

The hierarchical approach reduces search space dimensionality by factorizing the problem:

$$ \mathcal{S} = \mathcal{S}_{macro} \times \mathcal{S}_{micro} $$

Hardware-Aware Evolutionary NAS

Modern implementations incorporate hardware feedback loops:

  1. On-device latency measurements
  2. Energy consumption profiling
  3. Memory bandwidth constraints

This leads to hardware-specific Pareto-optimal architectures. For example, mobile-optimized networks often exhibit:

  • Depthwise separable convolutions
  • Heavy use of skip connections
  • Mixed precision quantization

Transferable Architecture Representations

Emerging methods learn transferable architecture embeddings that generalize across:

  • Different vision tasks (classification → segmentation)
  • Varying input resolutions
  • Distinct hardware platforms

The key innovation is the architecture embedding space E that captures generalizable building blocks:

$$ E: \mathcal{A} \rightarrow \mathbb{R}^d $$

where d is typically 32-256 dimensions. This enables few-shot adaptation to new tasks.

Emerging Trends and Hybrid Approaches – Genetic Algorithms in Neural Architecture Search – Tutorial Diagram
Diagram Description: The section describes hybrid GA-gradient pipelines and multi-objective optimization with Pareto fronts, which are inherently spatial concepts requiring visual representation of trade-offs and workflow stages.

6. Key Research Papers on GA-NAS

6.1 Key Research Papers on GA-NAS

  • Evolutionary NAS with Gene Expression Programming of Cellular Encoding — Abstract—The renaissance of neural architecture search (NAS) has seen classical methods such as genetic algorithms (GA) and genetic programming (GP) being exploited for convolutional neural network (CNN) architectures. While recent work have achieved promising performance on visual perception tasks, the direct encoding scheme of both GA and GP has functional com-plexity deficiency and does ...
  • NSGA-Net: Neural Architecture Search using Multi-Objective Genetic ... — NSGA-Net is a population-based search algorithm that explores a space of potential neural network architectures in three steps, namely, a population initialization step that is based on prior-knowledge from hand-crafted architectures, an exploration step comprising crossover and mutation of architec-tures, and finally an exploitation step that ...
  • A new genetic algorithm based evolutionary neural architecture search ... — Neural Architecture Search (NAS) which can design the DL network automatically has been widely investigated. However, many NAS methods suffer from the huge computation time. To overcome this drawback, this research proposed a new Evolutionary Neural Architecture Search with RepVGG nodes (EvoNAS-Rep).
  • PDF NSGA-Net: Neural Architecture Search using Multi-Objective — NSGA-Net is a population-based search algorithm that explores a space of potential neural network architectures in three steps, namely, a population initialization step that is based on prior-knowledge from hand-crafted architectures, an exploration step comprising crossover and mutation of architec-tures, and finally an exploitation step that ...
  • Evolutionary Neural Architecture Search and Its Applications in ... — Evolutionary algorithms (EAs) for NAS can find better solutions than human-designed architectures by exploring a large search space for possible architectures. Using multiobjective EAs for NAS, optimal neural architectures that meet various performance criteria can be explored and discovered efficiently.
  • Genetic-GNN: Evolutionary architecture search for Graph Neural Networks — Neural architecture search (NAS) has seen significant attention throughout the computational intelligence research community and has pushed forward the state-of-the-art of many neural models to address grid-like data such as texts and images. However, little work has been done on Graph Neural Network (GNN) models dedicated to unstructured network data. Given the huge number of choices and ...
  • Efficient evolutionary neural architecture search based on hybrid ... — Therefore, we propose an efficient Neural Architecture Search (NAS) method based on genetic algorithms. By designing an efficient hybrid search space, we aim to enhance network performance, achieving state-of-the-art levels on multi-image classification datasets.
  • Evolutionary design of neural network architectures: a review of three ... — We present a comprehensive review of the evolutionary design of neural network architectures. This work is motivated by the fact that the success of an Artificial Neural Network (ANN) highly depends on its architecture and among many approaches Evolutionary Computation, which is a set of global-search methods inspired by biological evolution has been proved to be an efficient approach for ...
  • PDF Genetic Algorithm-based Optimization of Generative Adversarial Networks ... — Design of the hyper-parameters of the GANs and the data pre-processing by Genetic Algorithm (GA) is presented in this study. GA is widely used in optimizing deep learning frameworks such as Convolutional Neural Networks and has achieved excellent results.
  • PDF Neural Networks using Genetic Algorithms - ijcaonline.org — This paper makes an effort to give a review with respect to neural networks, genetic algorithm and how they both work together. Genetic algorithm has three main operators: selection, mutation and crossover.

6.2 Recommended Books and Tutorials

  • Genetic-GNN: Evolutionary architecture search for Graph Neural Networks — To automate the model selection process, Neural Architecture Search (NAS) was widely adopted [11], [12], [13] and has been a focal point of deep learning research in recent years. NAS seeks to find an optimal combination of architecture components from a well-defined searching space and finally generates an integral model suitable for a target problem under study.
  • A new genetic algorithm based evolutionary neural architecture search ... — As the result, the Neural Architecture Search (NAS) has become a hot point and it has attracted increasingly attentions in the field [6]. NAS aims at searching the optimal DL architecture with the best performance in the automatic way, which can meet the urgent need of designing DL structure in various applications.
  • PDF Genetic Algorithms: Theory and Applications — tures has been achieved by refining and combining the genetic material over a long period of time. Generally speaking, genetic algorithms are simulations of evolution, of what kind ever. In most cases, however, genetic algorithms are nothing else than prob-abilistic optimization methods which are based on the principles of evolution.
  • S. Rajasekaran - Neural Networks, Fuzzy Logic and Genetic Algorithms ... — Genetic Algorithms have been chosen as the subject of discussion in this. book. Neural Networks are massively parallel, highly interconnected networks of. processing elements called neurons. Fuzzy Logic is an excellent mathematical tool to model uncertainty in. systems. Genetic Algorithms are unorthodox search and optimization algorithms
  • GitHub - giacomelli/GeneticSharp: GeneticSharp is a fast, extensible ... — GeneticSharp is a fast, extensible, multi-platform, and multithreading C# Genetic Algorithm library that simplifies the development of applications using Genetic Algorithms (GAs). It can be used in any kind of .NET 6, .NET Standard, and .NET Framework apps, like ASP .NET MVC, ASP .NET Core, Blazor, Web Forms, UWP, Windows Forms, GTK#, Xamarin ...
  • NSGA-Net: Neural Architecture Search using Multi-Objective Genetic ... — Deep Learning, Image classification, Neural Architecture Search, multi objective, Bayesian Optimization 1 INTRODUCTION Deep convolutional neural networks have been overwhelmingly suc-cessful in a variety of image analysis tasks. One of the key driving forces behind this success is the introduction of many CNN archi-
  • PDF Introduction to Genetic Algorithms - Michigan State University — GEC Summit, Shanghai, June, 2009 Genetic Algorithms: Are a method of search, often applied to optimization or learning Are stochastic - but are not random search Use an evolutionary analogy, "survival of fittest" Not fast in some sense; but sometimes more robust; scale relatively well, so can be useful Have extensions including Genetic Programming
  • PDF Introduction to Genetic Algorithms Introduction to Genetic — the basic genetic algorithm operation are also included. • Chapter 4 discusses the advanced operators and techniques involved in genetic algorithm. • The different classifications of genetic algorithm are provided in Chap. 5. Each of the classifications is discussed with their operators and mode of operation to achieve optimized solution.
  • Oliver Kramer Genetic Algorithm Essentials - Springer — Genetic Algorithms are the translation of the biological concept of evolu-tion into algorithmic recipes. They belong to the area of computer science related to machines and computer programs. As they are part of many intelligent systems, Genetic Algorithms are frequently counted to the areas of computational intelli-
  • 6 Neuroevolution optimization - Evolutionary Deep Learning: Genetic ... — Evolutionary DL is a term we use to encompass all evolutionary methods employed to improve DL. More specifically, the term neuroevolution has been used to define specific optimization patterns applied to DL. One such pattern we looked at in the last chapter was the application of evolutionary algorithms to HPO.

6.3 Open-Source Tools and Frameworks

  • Neural Architecture Search: Insights from 1000 Papers — In this survey, we provide an organized and comprehensive guide to neural architecture search. We give a taxonomy of search spaces, algorithms, and speedup techniques, and we discuss resources such as benchmarks, best practices, other surveys, and open-source libraries. Keywords: neural architecture search, automated machine learning, deep learning
  • Genetic algorithm - Cornell University Computational Optimization Open ... — Software tools and platforms that utilize Genetic Algorithms MATLAB: The Global Optimization Toolbox of MATLAB is widely used for engineering simulations and machine learning. Python: The DEAP and PyGAD in Python provide an environment for research and AI model optimization. OpenGA: The OpenGA is a free C++ GA library, which is open-source.
  • Genetic-GNN: Evolutionary architecture search for Graph Neural Networks — This verified the effectiveness of Genetic-GNN for graph neural network architecture search applied in the multi-label node classification task. Since Genetic-GNN directly evaluates the candidate GNN models and retains the improved models at every generation over the evolutionary process, it can always end up with finding a well-performed GNN ...
  • A new genetic algorithm based evolutionary neural architecture search ... — This research proposed a new Evolutionary Neural Architecture Search using RepVGG nodes (EvoNAS-Rep) for image classification. The main contributions can be summarized as: 1) A new encoding strategy is developed, and it can bi-directional map the fixed-length individuals to the variable-depth block structure to construct the DL model further.
  • Genetic Algorithm: Reviews, Implementations, and Applications — Furthermore, the genetic programming is fundamentally very distinct from another methodology to artificial intelligence, machine learning, neural networks, evolutionary structures, deep learning, or computational reasoning because of how it is genetically motivated; it performs its quest for a result of poverty within the framework of development.
  • Genetic Algorithm for Neural Network Architecture and ... - GitHub — About Genetic Algorithm for Neural Network Architecture and Hyperparameter Optimization and Neural Network Weight Optimization with Genetic Algorithm
  • Efficient evolutionary neural architecture search based on hybrid ... — Therefore, we propose an efficient Neural Architecture Search (NAS) method based on genetic algorithms. By designing an efficient hybrid search space, we aim to enhance network performance, achieving state-of-the-art levels on multi-image classification datasets.
  • PDF Introduction to Genetic Algorithms - Michigan State University — A little theory - why a GA works GA in Practice -- some modern variants GEC Summit, Shanghai, June, 2009 Genetic Algorithms: Are a method of search, often applied to optimization or learning Are stochastic - but are notrandom search Use an evolutionary analogy, "survival of fittest"
  • Genetic-GNN: Evolutionary architecture search for Graph Neural Networks — We formulated a graph neural network architecture search problem under the evolutionary searching framework which aims to optimize both model structures and hyper-parameters.
  • Jenetics: Java Genetic Algorithm Library — Jenetics is a Genetic Algorithm, Evolutionary Algorithm, Genetic Programming, and Multi-objective Optimization library, written in modern-day Java.