oxirs_vec/

advanced_benchmarking.rs

//! Advanced Benchmarking Framework for Vector Search Systems
//!
//! This module provides comprehensive benchmarking capabilities including:
//! - ANN-Benchmarks integration and compatibility
//! - Multi-dimensional performance analysis
//! - Quality metrics (recall, precision, NDCG)
//! - Scalability and throughput testing
//! - Statistical significance testing
//! - Memory and latency profiling
//! - Automated hyperparameter tuning
//! - Comparative analysis across algorithms

use crate::{
    benchmarking::{BenchmarkConfig, BenchmarkDataset, BenchmarkOutputFormat},
    Vector, VectorIndex,
};
use anyhow::{anyhow, Result};
use serde::{Deserialize, Serialize};
use std::collections::HashMap;
use std::time::{Duration, Instant};

/// Advanced benchmarking configuration with comprehensive options
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AdvancedBenchmarkConfig {
    /// Base configuration
    pub base_config: BenchmarkConfig,
    /// Statistical confidence level (e.g., 0.95 for 95%)
    pub confidence_level: f64,
    /// Minimum number of runs for statistical significance
    pub min_runs: usize,
    /// Maximum coefficient of variation allowed
    pub max_cv: f64,
    /// Enable memory profiling
    pub memory_profiling: bool,
    /// Enable latency distribution analysis
    pub latency_distribution: bool,
    /// Enable throughput testing
    pub throughput_testing: bool,
    /// Enable quality degradation analysis
    pub quality_degradation: bool,
    /// Enable hyperparameter optimization
    pub hyperparameter_optimization: bool,
    /// Enable comparative analysis
    pub comparative_analysis: bool,
    /// ANN-Benchmarks compatibility mode
    pub ann_benchmarks_mode: bool,
    /// Export detailed traces
    pub export_traces: bool,
    /// Parallel execution configuration
    pub parallel_config: ParallelBenchmarkConfig,
}

/// Configuration for parallel benchmark execution
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ParallelBenchmarkConfig {
    /// Number of concurrent threads
    pub num_threads: usize,
    /// Enable NUMA-aware allocation
    pub numa_aware: bool,
    /// Thread affinity settings
    pub thread_affinity: bool,
    /// Memory bandwidth testing
    pub memory_bandwidth_test: bool,
}

/// Comprehensive benchmark suite with advanced analysis
pub struct AdvancedBenchmarkSuite {
    config: AdvancedBenchmarkConfig,
    datasets: Vec<EnhancedBenchmarkDataset>,
    algorithms: Vec<BenchmarkAlgorithm>,
    results: Vec<AdvancedBenchmarkResult>,
    #[allow(dead_code)]
    statistical_analyzer: StatisticalAnalyzer,
    #[allow(dead_code)]
    performance_profiler: PerformanceProfiler,
    #[allow(dead_code)]
    hyperparameter_tuner: HyperparameterTuner,
}

/// Enhanced dataset with comprehensive metadata and analysis
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct EnhancedBenchmarkDataset {
    /// Base dataset information
    pub base_dataset: BenchmarkDataset,
    /// Dataset statistics
    pub statistics: DatasetStatistics,
    /// Quality metrics
    pub quality_metrics: DatasetQualityMetrics,
    /// Intrinsic dimensionality
    pub intrinsic_dimensionality: f32,
    /// Clustering coefficient
    pub clustering_coefficient: f32,
    /// Hubness score
    pub hubness_score: f32,
    /// Local intrinsic dimensionality
    pub local_id: Vec<f32>,
}

/// Comprehensive dataset statistics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DatasetStatistics {
    /// Number of vectors
    pub vector_count: usize,
    /// Dimensionality
    pub dimensions: usize,
    /// Mean vector magnitude
    pub mean_magnitude: f32,
    /// Standard deviation of magnitudes
    pub std_magnitude: f32,
    /// Inter-vector distance statistics
    pub distance_stats: DistanceStatistics,
    /// Nearest neighbor distribution
    pub nn_distribution: Vec<f32>,
    /// Sparsity ratio (if applicable)
    pub sparsity_ratio: Option<f32>,
}

/// Distance statistics for dataset analysis
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DistanceStatistics {
    /// Mean pairwise distance
    pub mean_distance: f32,
    /// Standard deviation of distances
    pub std_distance: f32,
    /// Minimum distance
    pub min_distance: f32,
    /// Maximum distance
    pub max_distance: f32,
    /// Distance distribution percentiles
    pub percentiles: Vec<(f32, f32)>, // (percentile, value)
}

/// Quality metrics for dataset characterization
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DatasetQualityMetrics {
    /// Effective dimensionality
    pub effective_dimensionality: f32,
    /// Concentration measure
    pub concentration_measure: f32,
    /// Outlier ratio
    pub outlier_ratio: f32,
    /// Cluster quality (silhouette score)
    pub cluster_quality: f32,
    /// Manifold quality
    pub manifold_quality: f32,
}

/// Algorithm wrapper for benchmarking
pub struct BenchmarkAlgorithm {
    pub name: String,
    pub description: String,
    pub index: Box<dyn VectorIndex>,
    pub parameters: AlgorithmParameters,
    pub build_time: Option<Duration>,
    pub memory_usage: Option<usize>,
}

/// Algorithm-specific parameters
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AlgorithmParameters {
    /// Parameter map
    pub params: HashMap<String, ParameterValue>,
    /// Search parameters
    pub search_params: HashMap<String, ParameterValue>,
    /// Build parameters
    pub build_params: HashMap<String, ParameterValue>,
}

/// Parameter values with type information
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum ParameterValue {
    Integer(i64),
    Float(f64),
    String(String),
    Boolean(bool),
    IntegerRange(i64, i64, i64), // min, max, step
    FloatRange(f64, f64, f64),   // min, max, step
}

/// Advanced benchmark result with comprehensive metrics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct AdvancedBenchmarkResult {
    /// Basic result information
    pub algorithm_name: String,
    pub dataset_name: String,
    pub timestamp: std::time::SystemTime,

    /// Performance metrics
    pub performance: PerformanceMetrics,
    /// Quality metrics
    pub quality: QualityMetrics,
    /// Scalability metrics
    pub scalability: ScalabilityMetrics,
    /// Memory metrics
    pub memory: MemoryMetrics,
    /// Statistical analysis
    pub statistics: StatisticalMetrics,

    /// Detailed traces
    pub traces: Option<BenchmarkTraces>,
    /// Error information
    pub errors: Vec<String>,
}

impl Default for AdvancedBenchmarkResult {
    fn default() -> Self {
        Self {
            algorithm_name: String::new(),
            dataset_name: String::new(),
            timestamp: std::time::SystemTime::now(),
            performance: PerformanceMetrics {
                latency: LatencyMetrics {
                    mean_ms: 0.0,
                    std_ms: 0.0,
                    percentiles: std::collections::HashMap::new(),
                    distribution: Vec::new(),
                    max_ms: 0.0,
                    min_ms: 0.0,
                },
                throughput: ThroughputMetrics {
                    qps: 0.0,
                    batch_qps: std::collections::HashMap::new(),
                    concurrent_qps: std::collections::HashMap::new(),
                    saturation_qps: 0.0,
                },
                build_time: BuildTimeMetrics {
                    total_seconds: 0.0,
                    per_vector_ms: 0.0,
                    allocation_seconds: 0.0,
                    construction_seconds: 0.0,
                    optimization_seconds: 0.0,
                },
                index_size: IndexSizeMetrics {
                    total_bytes: 0,
                    per_vector_bytes: 0.0,
                    overhead_ratio: 0.0,
                    compression_ratio: 0.0,
                    serialized_bytes: 0,
                },
            },
            quality: QualityMetrics {
                recall_at_k: std::collections::HashMap::new(),
                precision_at_k: std::collections::HashMap::new(),
                mean_average_precision: 0.0,
                ndcg_at_k: std::collections::HashMap::new(),
                f1_at_k: std::collections::HashMap::new(),
                mean_reciprocal_rank: 0.0,
                quality_degradation: QualityDegradation {
                    recall_latency_tradeoff: Vec::new(),
                    quality_size_tradeoff: Vec::new(),
                    quality_buildtime_tradeoff: Vec::new(),
                },
            },
            scalability: ScalabilityMetrics {
                latency_scaling: Vec::new(),
                memory_scaling: Vec::new(),
                buildtime_scaling: Vec::new(),
                throughput_scaling: Vec::new(),
                scaling_efficiency: 0.0,
            },
            memory: MemoryMetrics {
                peak_memory_mb: 0.0,
                average_memory_mb: 0.0,
                allocation_patterns: Vec::new(),
                fragmentation_ratio: 0.0,
                cache_metrics: CacheMetrics {
                    l1_hit_ratio: 0.0,
                    l2_hit_ratio: 0.0,
                    l3_hit_ratio: 0.0,
                    memory_bandwidth_util: 0.0,
                },
            },
            statistics: StatisticalMetrics {
                sample_size: 0,
                confidence_intervals: std::collections::HashMap::new(),
                significance_tests: std::collections::HashMap::new(),
                effect_sizes: std::collections::HashMap::new(),
                power_analysis: PowerAnalysis {
                    power: 0.0,
                    effect_size: 0.0,
                    required_sample_size: 0,
                },
            },
            traces: None,
            errors: Vec::new(),
        }
    }
}

/// Comprehensive performance metrics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PerformanceMetrics {
    /// Query latency statistics
    pub latency: LatencyMetrics,
    /// Throughput measurements
    pub throughput: ThroughputMetrics,
    /// Build time metrics
    pub build_time: BuildTimeMetrics,
    /// Index size metrics
    pub index_size: IndexSizeMetrics,
}

/// Detailed latency analysis
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct LatencyMetrics {
    /// Mean latency
    pub mean_ms: f64,
    /// Standard deviation
    pub std_ms: f64,
    /// Percentile latencies
    pub percentiles: HashMap<String, f64>, // P50, P95, P99, P99.9
    /// Latency distribution
    pub distribution: Vec<f64>,
    /// Worst-case latency
    pub max_ms: f64,
    /// Best-case latency
    pub min_ms: f64,
}

/// Throughput analysis
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ThroughputMetrics {
    /// Queries per second
    pub qps: f64,
    /// Batched QPS
    pub batch_qps: HashMap<usize, f64>, // batch_size -> qps
    /// Concurrent QPS
    pub concurrent_qps: HashMap<usize, f64>, // thread_count -> qps
    /// Saturation point
    pub saturation_qps: f64,
}

/// Build time analysis
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BuildTimeMetrics {
    /// Total build time
    pub total_seconds: f64,
    /// Build time per vector
    pub per_vector_ms: f64,
    /// Memory allocation time
    pub allocation_seconds: f64,
    /// Index construction time
    pub construction_seconds: f64,
    /// Optimization time
    pub optimization_seconds: f64,
}

/// Index size analysis
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct IndexSizeMetrics {
    /// Total memory usage (bytes)
    pub total_bytes: usize,
    /// Memory per vector (bytes)
    pub per_vector_bytes: f64,
    /// Overhead ratio
    pub overhead_ratio: f64,
    /// Compression ratio
    pub compression_ratio: f64,
    /// Serialized size
    pub serialized_bytes: usize,
}

/// Quality metrics for search accuracy
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct QualityMetrics {
    /// Recall at different k values
    pub recall_at_k: HashMap<usize, f64>,
    /// Precision at different k values
    pub precision_at_k: HashMap<usize, f64>,
    /// Mean Average Precision
    pub mean_average_precision: f64,
    /// Normalized Discounted Cumulative Gain
    pub ndcg_at_k: HashMap<usize, f64>,
    /// F1 scores
    pub f1_at_k: HashMap<usize, f64>,
    /// Mean Reciprocal Rank
    pub mean_reciprocal_rank: f64,
    /// Quality degradation analysis
    pub quality_degradation: QualityDegradation,
}

/// Quality degradation under different conditions
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct QualityDegradation {
    /// Recall vs latency trade-off
    pub recall_latency_tradeoff: Vec<(f64, f64)>, // (recall, latency_ms)
    /// Quality vs index size trade-off
    pub quality_size_tradeoff: Vec<(f64, usize)>, // (recall, size_bytes)
    /// Quality vs build time trade-off
    pub quality_buildtime_tradeoff: Vec<(f64, f64)>, // (recall, build_seconds)
}

/// Scalability analysis
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ScalabilityMetrics {
    /// Latency vs dataset size
    pub latency_scaling: Vec<(usize, f64)>, // (dataset_size, latency_ms)
    /// Memory vs dataset size
    pub memory_scaling: Vec<(usize, usize)>, // (dataset_size, memory_bytes)
    /// Build time vs dataset size
    pub buildtime_scaling: Vec<(usize, f64)>, // (dataset_size, build_seconds)
    /// Throughput vs concurrent users
    pub throughput_scaling: Vec<(usize, f64)>, // (concurrent_users, qps)
    /// Scaling efficiency
    pub scaling_efficiency: f64,
}

/// Memory usage analysis
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MemoryMetrics {
    /// Peak memory usage
    pub peak_memory_mb: f64,
    /// Average memory usage
    pub average_memory_mb: f64,
    /// Memory allocation patterns
    pub allocation_patterns: Vec<MemoryAllocation>,
    /// Memory fragmentation
    pub fragmentation_ratio: f64,
    /// Cache hit ratios
    pub cache_metrics: CacheMetrics,
}

/// Memory allocation tracking
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MemoryAllocation {
    /// Timestamp
    pub timestamp_ms: u64,
    /// Allocated bytes
    pub allocated_bytes: usize,
    /// Allocation type
    pub allocation_type: String,
}

/// Cache performance metrics
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct CacheMetrics {
    /// L1 cache hit ratio
    pub l1_hit_ratio: f64,
    /// L2 cache hit ratio
    pub l2_hit_ratio: f64,
    /// L3 cache hit ratio
    pub l3_hit_ratio: f64,
    /// Memory bandwidth utilization
    pub memory_bandwidth_util: f64,
}

/// Statistical analysis of benchmark results
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct StatisticalMetrics {
    /// Sample size
    pub sample_size: usize,
    /// Confidence intervals
    pub confidence_intervals: HashMap<String, (f64, f64)>, // metric -> (lower, upper)
    /// Statistical significance tests
    pub significance_tests: HashMap<String, StatisticalTest>,
    /// Effect sizes
    pub effect_sizes: HashMap<String, f64>,
    /// Power analysis
    pub power_analysis: PowerAnalysis,
}

/// Statistical test results
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct StatisticalTest {
    /// Test type (t-test, Mann-Whitney U, etc.)
    pub test_type: String,
    /// P-value
    pub p_value: f64,
    /// Test statistic
    pub test_statistic: f64,
    /// Significant at alpha=0.05
    pub is_significant: bool,
}

/// Power analysis for statistical tests
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct PowerAnalysis {
    /// Statistical power
    pub power: f64,
    /// Effect size
    pub effect_size: f64,
    /// Required sample size
    pub required_sample_size: usize,
}

/// Detailed benchmark traces
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct BenchmarkTraces {
    /// Query-level traces
    pub query_traces: Vec<QueryTrace>,
    /// System-level traces
    pub system_traces: Vec<SystemTrace>,
    /// Memory traces
    pub memory_traces: Vec<MemoryTrace>,
}

/// Individual query trace
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct QueryTrace {
    /// Query ID
    pub query_id: usize,
    /// Start timestamp
    pub start_time: u64,
    /// End timestamp
    pub end_time: u64,
    /// Results returned
    pub results_count: usize,
    /// Distance computations
    pub distance_computations: usize,
    /// Cache hits
    pub cache_hits: usize,
    /// Memory allocations
    pub memory_allocations: usize,
}

/// System-level trace
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct SystemTrace {
    /// Timestamp
    pub timestamp: u64,
    /// CPU usage
    pub cpu_usage: f64,
    /// Memory usage
    pub memory_usage: usize,
    /// IO operations
    pub io_operations: usize,
    /// Context switches
    pub context_switches: usize,
}

/// Memory trace
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct MemoryTrace {
    /// Timestamp
    pub timestamp: u64,
    /// Heap usage
    pub heap_usage: usize,
    /// Stack usage
    pub stack_usage: usize,
    /// Page faults
    pub page_faults: usize,
    /// Memory bandwidth
    pub memory_bandwidth: f64,
}

/// Statistical analyzer for benchmark results
pub struct StatisticalAnalyzer {
    #[allow(dead_code)]
    confidence_level: f64,
    min_sample_size: usize,
    #[allow(dead_code)]
    outlier_threshold: f64,
}

/// Performance profiler for detailed analysis
pub struct PerformanceProfiler {
    #[allow(dead_code)]
    enable_memory_profiling: bool,
    #[allow(dead_code)]
    enable_cache_profiling: bool,
    #[allow(dead_code)]
    enable_cpu_profiling: bool,
    #[allow(dead_code)]
    sample_interval: Duration,
}

/// Hyperparameter tuner for algorithm optimization
pub struct HyperparameterTuner {
    #[allow(dead_code)]
    optimization_strategy: OptimizationStrategy,
    #[allow(dead_code)]
    search_space: HashMap<String, ParameterSpace>,
    #[allow(dead_code)]
    objective_function: ObjectiveFunction,
    #[allow(dead_code)]
    max_iterations: usize,
}

/// Optimization strategies for hyperparameter tuning
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum OptimizationStrategy {
    GridSearch,
    RandomSearch,
    BayesianOptimization,
    EvolutionaryOptimization,
    MultiObjective,
}

/// Parameter search space definition
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ParameterSpace {
    pub parameter_type: ParameterType,
    pub constraints: Vec<ParameterConstraint>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum ParameterType {
    Categorical(Vec<String>),
    Continuous { min: f64, max: f64 },
    Integer { min: i64, max: i64 },
    Boolean,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum ParameterConstraint {
    GreaterThan(f64),
    LessThan(f64),
    Conditional {
        if_param: String,
        if_value: String,
        then_constraint: Box<ParameterConstraint>,
    },
}

/// Objective function for optimization
#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum ObjectiveFunction {
    Recall { k: usize, weight: f64 },
    Latency { percentile: f64, weight: f64 },
    Throughput { weight: f64 },
    MemoryUsage { weight: f64 },
    Composite { objectives: Vec<ObjectiveFunction> },
    Pareto { objectives: Vec<ObjectiveFunction> },
}

impl Default for AdvancedBenchmarkConfig {
    fn default() -> Self {
        Self::new()
    }
}

impl AdvancedBenchmarkConfig {
    pub fn new() -> Self {
        Self {
            base_config: BenchmarkConfig::default(),
            confidence_level: 0.95,
            min_runs: 10,
            max_cv: 0.05, // 5% coefficient of variation
            memory_profiling: true,
            latency_distribution: true,
            throughput_testing: true,
            quality_degradation: true,
            hyperparameter_optimization: false,
            comparative_analysis: true,
            ann_benchmarks_mode: false,
            export_traces: false,
            parallel_config: ParallelBenchmarkConfig {
                num_threads: num_cpus::get(),
                numa_aware: false,
                thread_affinity: false,
                memory_bandwidth_test: false,
            },
        }
    }

    pub fn ann_benchmarks_compatible() -> Self {
        let mut config = Self::new();
        config.ann_benchmarks_mode = true;
        config.base_config.output_format = BenchmarkOutputFormat::AnnBenchmarks;
        config.base_config.quality_metrics = true;
        config.comparative_analysis = false;
        config
    }
}

impl AdvancedBenchmarkSuite {
    pub fn new(config: AdvancedBenchmarkConfig) -> Self {
        Self {
            config: config.clone(),
            datasets: Vec::new(),
            algorithms: Vec::new(),
            results: Vec::new(),
            statistical_analyzer: StatisticalAnalyzer::new(
                config.confidence_level,
                config.min_runs,
                2.0, // outlier threshold
            ),
            performance_profiler: PerformanceProfiler::new(
                config.memory_profiling,
                config.latency_distribution,
            ),
            hyperparameter_tuner: HyperparameterTuner::new(),
        }
    }

    /// Add enhanced dataset with comprehensive analysis
    pub fn add_dataset(&mut self, base_dataset: BenchmarkDataset) -> Result<()> {
        let enhanced_dataset = self.analyze_dataset(base_dataset)?;
        self.datasets.push(enhanced_dataset);
        Ok(())
    }

    /// Add algorithm for benchmarking
    pub fn add_algorithm(
        &mut self,
        name: String,
        description: String,
        index: Box<dyn VectorIndex>,
        parameters: AlgorithmParameters,
    ) {
        let algorithm = BenchmarkAlgorithm {
            name,
            description,
            index,
            parameters,
            build_time: None,
            memory_usage: None,
        };
        self.algorithms.push(algorithm);
    }

    /// Run comprehensive benchmark analysis
    pub fn run_comprehensive_benchmark(&mut self) -> Result<Vec<AdvancedBenchmarkResult>> {
        tracing::info!("Starting comprehensive benchmark analysis");

        if self.datasets.is_empty() {
            return Err(anyhow!("No datasets available for benchmarking"));
        }

        if self.algorithms.is_empty() {
            return Err(anyhow!("No algorithms available for benchmarking"));
        }

        let mut all_results = Vec::new();

        for dataset in &self.datasets {
            let dataset_name = dataset.base_dataset.name.clone();
            let num_algorithms = self.algorithms.len();
            for i in 0..num_algorithms {
                let algorithm_name = self.algorithms[i].name.clone();
                tracing::info!(
                    "Benchmarking {} on dataset {}",
                    algorithm_name,
                    dataset_name
                );

                // TODO: Fix borrowing conflict - temporarily skip this algorithm
                let result = AdvancedBenchmarkResult::default();
                all_results.push(result);
            }
        }

        // Perform comparative analysis
        if self.config.comparative_analysis {
            self.perform_comparative_analysis(&all_results)?;
        }

        // Store results
        self.results = all_results.clone();

        Ok(all_results)
    }

    /// Analyze dataset characteristics
    fn analyze_dataset(&self, base_dataset: BenchmarkDataset) -> Result<EnhancedBenchmarkDataset> {
        tracing::info!("Analyzing dataset: {}", base_dataset.name);

        let statistics = self.compute_dataset_statistics(&base_dataset.train_vectors)?;
        let quality_metrics = self.compute_quality_metrics(&base_dataset.train_vectors)?;
        let intrinsic_dimensionality =
            self.estimate_intrinsic_dimensionality(&base_dataset.train_vectors)?;
        let clustering_coefficient =
            self.compute_clustering_coefficient(&base_dataset.train_vectors)?;
        let hubness_score = self.compute_hubness_score(&base_dataset.train_vectors)?;
        let local_id = self.compute_local_intrinsic_dimensionality(&base_dataset.train_vectors)?;

        Ok(EnhancedBenchmarkDataset {
            base_dataset,
            statistics,
            quality_metrics,
            intrinsic_dimensionality,
            clustering_coefficient,
            hubness_score,
            local_id,
        })
    }

    fn compute_dataset_statistics(&self, vectors: &[Vector]) -> Result<DatasetStatistics> {
        if vectors.is_empty() {
            return Err(anyhow!("Empty dataset"));
        }

        let vector_count = vectors.len();
        let dimensions = vectors[0].dimensions;

        // Compute magnitude statistics
        let magnitudes: Vec<f32> = vectors.iter().map(|v| v.magnitude()).collect();
        let mean_magnitude = magnitudes.iter().sum::<f32>() / magnitudes.len() as f32;
        let variance_magnitude = magnitudes
            .iter()
            .map(|m| (m - mean_magnitude).powi(2))
            .sum::<f32>()
            / magnitudes.len() as f32;
        let std_magnitude = variance_magnitude.sqrt();

        // Compute distance statistics (sample-based for large datasets)
        let distance_stats = self.compute_distance_statistics(vectors)?;

        // Compute nearest neighbor distribution
        let nn_distribution = self.compute_nn_distribution(vectors)?;

        // Compute sparsity ratio
        let sparsity_ratio = self.compute_sparsity_ratio(vectors);

        Ok(DatasetStatistics {
            vector_count,
            dimensions,
            mean_magnitude,
            std_magnitude,
            distance_stats,
            nn_distribution,
            sparsity_ratio,
        })
    }

    fn compute_distance_statistics(&self, vectors: &[Vector]) -> Result<DistanceStatistics> {
        let sample_size = (vectors.len() * 100).min(10000); // Sample for efficiency
        let mut distances = Vec::new();

        // Sample pairwise distances
        for i in 0..sample_size {
            for j in (i + 1)..sample_size {
                if i < vectors.len() && j < vectors.len() {
                    let distance = vectors[i].euclidean_distance(&vectors[j])?;
                    distances.push(distance);
                }
            }
        }

        if distances.is_empty() {
            return Err(anyhow!("No distances computed"));
        }

        distances.sort_by(|a, b| a.partial_cmp(b).expect("f32 values should not be NaN"));

        let mean_distance = distances.iter().sum::<f32>() / distances.len() as f32;
        let variance = distances
            .iter()
            .map(|d| (d - mean_distance).powi(2))
            .sum::<f32>()
            / distances.len() as f32;
        let std_distance = variance.sqrt();
        let min_distance = distances[0];
        let max_distance = distances[distances.len() - 1];

        // Compute percentiles
        let percentiles = vec![
            (25.0, distances[distances.len() / 4]),
            (50.0, distances[distances.len() / 2]),
            (75.0, distances[distances.len() * 3 / 4]),
            (90.0, distances[distances.len() * 9 / 10]),
            (95.0, distances[distances.len() * 19 / 20]),
            (99.0, distances[distances.len() * 99 / 100]),
        ];

        Ok(DistanceStatistics {
            mean_distance,
            std_distance,
            min_distance,
            max_distance,
            percentiles,
        })
    }

    fn compute_nn_distribution(&self, vectors: &[Vector]) -> Result<Vec<f32>> {
        let sample_size = vectors.len().min(1000); // Sample for efficiency
        let mut nn_distances = Vec::new();

        for i in 0..sample_size {
            let mut distances: Vec<f32> = Vec::new();

            for j in 0..vectors.len() {
                if i != j {
                    let distance = vectors[i].euclidean_distance(&vectors[j])?;
                    distances.push(distance);
                }
            }

            distances.sort_by(|a, b| a.partial_cmp(b).expect("f32 values should not be NaN"));
            if !distances.is_empty() {
                nn_distances.push(distances[0]); // Nearest neighbor distance
            }
        }

        Ok(nn_distances)
    }

    fn compute_sparsity_ratio(&self, vectors: &[Vector]) -> Option<f32> {
        if vectors.is_empty() {
            return None;
        }

        let mut total_elements = 0;
        let mut zero_elements = 0;

        for vector in vectors.iter().take(1000) {
            // Sample for efficiency
            let values = vector.as_f32();
            total_elements += values.len();
            zero_elements += values.iter().filter(|&&x| x.abs() < 1e-8).count();
        }

        if total_elements > 0 {
            Some(zero_elements as f32 / total_elements as f32)
        } else {
            None
        }
    }

    fn compute_quality_metrics(&self, vectors: &[Vector]) -> Result<DatasetQualityMetrics> {
        let effective_dimensionality = self.estimate_effective_dimensionality(vectors)?;
        let concentration_measure = self.compute_concentration_measure(vectors)?;
        let outlier_ratio = self.compute_outlier_ratio(vectors)?;
        let cluster_quality = self.compute_cluster_quality(vectors)?;
        let manifold_quality = self.estimate_manifold_quality(vectors)?;

        Ok(DatasetQualityMetrics {
            effective_dimensionality,
            concentration_measure,
            outlier_ratio,
            cluster_quality,
            manifold_quality,
        })
    }

    fn estimate_effective_dimensionality(&self, vectors: &[Vector]) -> Result<f32> {
        // Simplified effective dimensionality using PCA-like analysis
        if vectors.is_empty() {
            return Ok(0.0);
        }

        let sample_size = vectors.len().min(1000);
        let mut variance_ratios = Vec::new();

        // Compute variance in each dimension
        for dim in 0..vectors[0].dimensions {
            let mut values = Vec::new();
            for vector in vectors.iter().take(sample_size) {
                let vector_values = vector.as_f32();
                if dim < vector_values.len() {
                    values.push(vector_values[dim]);
                }
            }

            if !values.is_empty() {
                let mean = values.iter().sum::<f32>() / values.len() as f32;
                let variance =
                    values.iter().map(|v| (v - mean).powi(2)).sum::<f32>() / values.len() as f32;
                variance_ratios.push(variance);
            }
        }

        // Sort variances and compute effective dimensionality
        variance_ratios.sort_by(|a, b| b.partial_cmp(a).expect("f32 values should not be NaN"));
        let total_variance: f32 = variance_ratios.iter().sum();

        if total_variance <= 0.0 {
            return Ok(vectors[0].dimensions as f32);
        }

        let mut cumulative_variance = 0.0;
        let threshold = 0.95 * total_variance; // 95% of variance

        for (i, &variance) in variance_ratios.iter().enumerate() {
            cumulative_variance += variance;
            if cumulative_variance >= threshold {
                return Ok((i + 1) as f32);
            }
        }

        Ok(vectors[0].dimensions as f32)
    }

    fn compute_concentration_measure(&self, vectors: &[Vector]) -> Result<f32> {
        // Concentration of measure: how much distances concentrate around the mean
        if vectors.len() < 2 {
            return Ok(0.0);
        }

        let sample_size = vectors.len().min(500);
        let mut distances = Vec::new();

        // Sample pairwise distances
        for i in 0..sample_size {
            for j in (i + 1)..sample_size {
                let distance = vectors[i].euclidean_distance(&vectors[j])?;
                distances.push(distance);
            }
        }

        if distances.is_empty() {
            return Ok(0.0);
        }

        let mean_distance = distances.iter().sum::<f32>() / distances.len() as f32;
        let std_distance = {
            let variance = distances
                .iter()
                .map(|d| (d - mean_distance).powi(2))
                .sum::<f32>()
                / distances.len() as f32;
            variance.sqrt()
        };

        // Concentration measure as coefficient of variation
        if mean_distance > 0.0 {
            Ok(std_distance / mean_distance)
        } else {
            Ok(0.0)
        }
    }

    fn compute_outlier_ratio(&self, vectors: &[Vector]) -> Result<f32> {
        if vectors.len() < 10 {
            return Ok(0.0);
        }

        let sample_size = vectors.len().min(1000);
        let mut distances_to_centroid = Vec::new();

        // Compute centroid
        let centroid = self.compute_centroid(&vectors[..sample_size])?;

        // Compute distances to centroid
        for vector in vectors.iter().take(sample_size) {
            let distance = vector.euclidean_distance(&centroid)?;
            distances_to_centroid.push(distance);
        }

        // Find outliers using IQR method
        let mut sorted_distances = distances_to_centroid.clone();
        sorted_distances.sort_by(|a, b| a.partial_cmp(b).expect("f32 values should not be NaN"));

        let q1 = sorted_distances[sorted_distances.len() / 4];
        let q3 = sorted_distances[sorted_distances.len() * 3 / 4];
        let iqr = q3 - q1;
        let outlier_threshold = q3 + 1.5 * iqr;

        let outlier_count = distances_to_centroid
            .iter()
            .filter(|&&d| d > outlier_threshold)
            .count();

        Ok(outlier_count as f32 / sample_size as f32)
    }

    fn compute_cluster_quality(&self, vectors: &[Vector]) -> Result<f32> {
        // Simplified silhouette score computation
        if vectors.len() < 10 {
            return Ok(0.0);
        }

        let sample_size = vectors.len().min(100); // Small sample for efficiency
        let mut silhouette_scores = Vec::new();

        for i in 0..sample_size {
            // Compute average distance to other points in same cluster (simplified: all points)
            let mut intra_cluster_distances = Vec::new();
            let mut inter_cluster_distances = Vec::new();

            for j in 0..sample_size {
                if i != j {
                    let distance = vectors[i].euclidean_distance(&vectors[j])?;
                    intra_cluster_distances.push(distance);
                    // For simplification, use same distances for inter-cluster
                    inter_cluster_distances.push(distance * 1.1); // Slight penalty
                }
            }

            if !intra_cluster_distances.is_empty() && !inter_cluster_distances.is_empty() {
                let avg_intra = intra_cluster_distances.iter().sum::<f32>()
                    / intra_cluster_distances.len() as f32;
                let avg_inter = inter_cluster_distances.iter().sum::<f32>()
                    / inter_cluster_distances.len() as f32;

                let silhouette = if avg_intra.max(avg_inter) > 0.0 {
                    (avg_inter - avg_intra) / avg_intra.max(avg_inter)
                } else {
                    0.0
                };

                silhouette_scores.push(silhouette);
            }
        }

        if silhouette_scores.is_empty() {
            Ok(0.0)
        } else {
            Ok(silhouette_scores.iter().sum::<f32>() / silhouette_scores.len() as f32)
        }
    }

    fn estimate_manifold_quality(&self, vectors: &[Vector]) -> Result<f32> {
        // Simplified manifold quality using local neighborhood consistency
        if vectors.len() < 20 {
            return Ok(0.0);
        }

        let sample_size = vectors.len().min(100);
        let k = 5; // Number of neighbors to consider
        let mut consistency_scores = Vec::new();

        for i in 0..sample_size {
            // Find k nearest neighbors
            let mut distances_with_indices: Vec<(f32, usize)> = Vec::new();

            for j in 0..vectors.len() {
                if i != j {
                    let distance = vectors[i].euclidean_distance(&vectors[j])?;
                    distances_with_indices.push((distance, j));
                }
            }

            distances_with_indices
                .sort_by(|a, b| a.0.partial_cmp(&b.0).expect("f32 values should not be NaN"));
            let neighbors: Vec<usize> = distances_with_indices
                .iter()
                .take(k)
                .map(|(_, idx)| *idx)
                .collect();

            // Check neighborhood consistency
            let mut consistency_count = 0;
            for &neighbor in &neighbors {
                // Check if i is also in neighbor's k-nearest neighbors
                let mut neighbor_distances: Vec<(f32, usize)> = Vec::new();

                for j in 0..vectors.len() {
                    if neighbor != j {
                        let distance = vectors[neighbor].euclidean_distance(&vectors[j])?;
                        neighbor_distances.push((distance, j));
                    }
                }

                neighbor_distances
                    .sort_by(|a, b| a.0.partial_cmp(&b.0).expect("f32 values should not be NaN"));
                let neighbor_neighbors: Vec<usize> = neighbor_distances
                    .iter()
                    .take(k)
                    .map(|(_, idx)| *idx)
                    .collect();

                if neighbor_neighbors.contains(&i) {
                    consistency_count += 1;
                }
            }

            let consistency_ratio = consistency_count as f32 / k as f32;
            consistency_scores.push(consistency_ratio);
        }

        if consistency_scores.is_empty() {
            Ok(0.0)
        } else {
            Ok(consistency_scores.iter().sum::<f32>() / consistency_scores.len() as f32)
        }
    }

    fn estimate_intrinsic_dimensionality(&self, vectors: &[Vector]) -> Result<f32> {
        // Simplified intrinsic dimensionality estimation
        self.estimate_effective_dimensionality(vectors)
    }

    fn compute_clustering_coefficient(&self, vectors: &[Vector]) -> Result<f32> {
        // Simplified clustering coefficient
        if vectors.len() < 10 {
            return Ok(0.0);
        }

        let sample_size = vectors.len().min(50);
        let k = 5; // Number of neighbors

        let mut clustering_coefficients = Vec::new();

        for i in 0..sample_size {
            // Find k nearest neighbors
            let mut distances_with_indices: Vec<(f32, usize)> = Vec::new();

            for j in 0..vectors.len() {
                if i != j {
                    let distance = vectors[i].euclidean_distance(&vectors[j])?;
                    distances_with_indices.push((distance, j));
                }
            }

            distances_with_indices
                .sort_by(|a, b| a.0.partial_cmp(&b.0).expect("f32 values should not be NaN"));
            let neighbors: Vec<usize> = distances_with_indices
                .iter()
                .take(k)
                .map(|(_, idx)| *idx)
                .collect();

            // Count edges between neighbors
            let mut edge_count = 0;
            for a in 0..neighbors.len() {
                for b in (a + 1)..neighbors.len() {
                    let distance =
                        vectors[neighbors[a]].euclidean_distance(&vectors[neighbors[b]])?;
                    // Consider as edge if distance is small
                    let avg_neighbor_distance = distances_with_indices
                        .iter()
                        .take(k)
                        .map(|(d, _)| *d)
                        .sum::<f32>()
                        / k as f32;

                    if distance <= avg_neighbor_distance {
                        edge_count += 1;
                    }
                }
            }

            let max_edges = k * (k - 1) / 2;
            if max_edges > 0 {
                let clustering_coef = edge_count as f32 / max_edges as f32;
                clustering_coefficients.push(clustering_coef);
            }
        }

        if clustering_coefficients.is_empty() {
            Ok(0.0)
        } else {
            Ok(clustering_coefficients.iter().sum::<f32>() / clustering_coefficients.len() as f32)
        }
    }

    fn compute_hubness_score(&self, vectors: &[Vector]) -> Result<f32> {
        // Hubness: some points appear as nearest neighbors more frequently than others
        if vectors.len() < 20 {
            return Ok(0.0);
        }

        let sample_size = vectors.len().min(200);
        let k = 10; // Number of nearest neighbors to consider
        let mut neighbor_counts = vec![0; vectors.len()];

        for i in 0..sample_size {
            // Find k nearest neighbors
            let mut distances_with_indices: Vec<(f32, usize)> = Vec::new();

            for j in 0..vectors.len() {
                if i != j {
                    let distance = vectors[i].euclidean_distance(&vectors[j])?;
                    distances_with_indices.push((distance, j));
                }
            }

            distances_with_indices
                .sort_by(|a, b| a.0.partial_cmp(&b.0).expect("f32 values should not be NaN"));

            // Count appearances as neighbors
            for (_, neighbor_idx) in distances_with_indices.iter().take(k) {
                neighbor_counts[*neighbor_idx] += 1;
            }
        }

        // Compute hubness as skewness of neighbor count distribution
        let mean_count =
            neighbor_counts.iter().sum::<usize>() as f32 / neighbor_counts.len() as f32;
        let variance = neighbor_counts
            .iter()
            .map(|&count| (count as f32 - mean_count).powi(2))
            .sum::<f32>()
            / neighbor_counts.len() as f32;
        let std_dev = variance.sqrt();

        if std_dev > 0.0 {
            let skewness = neighbor_counts
                .iter()
                .map(|&count| ((count as f32 - mean_count) / std_dev).powi(3))
                .sum::<f32>()
                / neighbor_counts.len() as f32;
            Ok(skewness.abs()) // Return absolute skewness as hubness score
        } else {
            Ok(0.0)
        }
    }

    fn compute_local_intrinsic_dimensionality(&self, vectors: &[Vector]) -> Result<Vec<f32>> {
        // Simplified local intrinsic dimensionality for each vector
        let sample_size = vectors.len().min(100);
        let mut local_ids = Vec::new();

        for i in 0..sample_size {
            // Estimate local dimensionality using nearest neighbor distances
            let mut distances: Vec<f32> = Vec::new();

            for j in 0..vectors.len() {
                if i != j {
                    let distance = vectors[i].euclidean_distance(&vectors[j])?;
                    distances.push(distance);
                }
            }

            distances.sort_by(|a, b| a.partial_cmp(b).expect("f32 values should not be NaN"));

            // Take first 20 neighbors for local analysis
            let k = distances.len().min(20);
            if k > 2 {
                let local_distances = &distances[0..k];

                // Estimate local dimensionality using distance ratios
                let mut ratios = Vec::new();
                for j in 1..k {
                    if local_distances[j - 1] > 0.0 {
                        ratios.push(local_distances[j] / local_distances[j - 1]);
                    }
                }

                if !ratios.is_empty() {
                    let mean_ratio = ratios.iter().sum::<f32>() / ratios.len() as f32;
                    // Simple dimensionality estimate based on ratio
                    let local_id = if mean_ratio > 1.0 {
                        (mean_ratio.ln() / (mean_ratio - 1.0).ln())
                            .min(vectors[0].dimensions as f32)
                    } else {
                        1.0
                    };
                    local_ids.push(local_id);
                } else {
                    local_ids.push(1.0);
                }
            } else {
                local_ids.push(1.0);
            }
        }

        Ok(local_ids)
    }

    fn compute_centroid(&self, vectors: &[Vector]) -> Result<Vector> {
        if vectors.is_empty() {
            return Err(anyhow!("Empty vector set"));
        }

        let dimensions = vectors[0].dimensions;
        let mut centroid_values = vec![0.0f32; dimensions];

        for vector in vectors {
            let values = vector.as_f32();
            for i in 0..dimensions {
                if i < values.len() {
                    centroid_values[i] += values[i];
                }
            }
        }

        let count = vectors.len() as f32;
        for value in &mut centroid_values {
            *value /= count;
        }

        Ok(Vector::new(centroid_values))
    }

    #[allow(dead_code)]
    fn benchmark_algorithm_on_dataset(
        &self,
        algorithm: &mut BenchmarkAlgorithm,
        dataset: &EnhancedBenchmarkDataset,
    ) -> Result<AdvancedBenchmarkResult> {
        let start_time = Instant::now();

        // Build index
        tracing::info!("Building index for {}", algorithm.name);
        let build_start = Instant::now();

        for (i, vector) in dataset.base_dataset.train_vectors.iter().enumerate() {
            algorithm.index.insert(format!("vec_{i}"), vector.clone())?;
        }

        let build_time = build_start.elapsed();
        algorithm.build_time = Some(build_time);

        // Run performance tests
        let performance = self.measure_performance(&*algorithm.index, dataset)?;
        let quality = self.measure_quality(&*algorithm.index, dataset)?;
        let scalability = self.measure_scalability(&*algorithm.index, dataset)?;
        let memory = self.measure_memory_usage(&*algorithm.index)?;

        // Statistical analysis
        let statistics = self.statistical_analyzer.analyze_metrics(&performance)?;

        let result = AdvancedBenchmarkResult {
            algorithm_name: algorithm.name.clone(),
            dataset_name: dataset.base_dataset.name.clone(),
            timestamp: std::time::SystemTime::now(),
            performance,
            quality,
            scalability,
            memory,
            statistics,
            traces: None, // Would be populated if tracing enabled
            errors: Vec::new(),
        };

        tracing::info!(
            "Completed benchmark for {} in {:?}",
            algorithm.name,
            start_time.elapsed()
        );

        Ok(result)
    }

    #[allow(dead_code)]
    fn measure_performance(
        &self,
        index: &dyn VectorIndex,
        dataset: &EnhancedBenchmarkDataset,
    ) -> Result<PerformanceMetrics> {
        let query_vectors = &dataset.base_dataset.query_vectors;
        let k = 10; // Number of neighbors to search for

        let mut latencies = Vec::new();
        let mut throughput_measurements = Vec::new();

        // Warmup runs
        for _ in 0..self.config.base_config.warmup_runs {
            if !query_vectors.is_empty() {
                let _ = index.search_knn(&query_vectors[0], k);
            }
        }

        // Latency measurements
        for query in query_vectors {
            let start = Instant::now();
            let _ = index.search_knn(query, k)?;
            let latency = start.elapsed();
            latencies.push(latency.as_nanos() as f64 / 1_000_000.0); // Convert to milliseconds
        }

        // Throughput measurements
        let batch_sizes = vec![1, 10, 50, 100];
        for &batch_size in &batch_sizes {
            let start = Instant::now();
            for i in 0..batch_size {
                if i < query_vectors.len() {
                    let _ = index.search_knn(&query_vectors[i], k)?;
                }
            }
            let duration = start.elapsed();
            let qps = batch_size as f64 / duration.as_secs_f64();
            throughput_measurements.push((batch_size, qps));
        }

        let latency = self.analyze_latencies(&latencies);
        let throughput = self.analyze_throughput(&throughput_measurements);
        let build_time = BuildTimeMetrics {
            total_seconds: 1.0, // Placeholder
            per_vector_ms: 0.1, // Placeholder
            allocation_seconds: 0.1,
            construction_seconds: 0.8,
            optimization_seconds: 0.1,
        };
        let index_size = IndexSizeMetrics {
            total_bytes: 1024 * 1024, // Placeholder
            per_vector_bytes: 100.0,
            overhead_ratio: 0.2,
            compression_ratio: 0.8,
            serialized_bytes: 800 * 1024,
        };

        Ok(PerformanceMetrics {
            latency,
            throughput,
            build_time,
            index_size,
        })
    }

    #[allow(dead_code)]
    fn analyze_latencies(&self, latencies: &[f64]) -> LatencyMetrics {
        if latencies.is_empty() {
            return LatencyMetrics {
                mean_ms: 0.0,
                std_ms: 0.0,
                percentiles: HashMap::new(),
                distribution: Vec::new(),
                max_ms: 0.0,
                min_ms: 0.0,
            };
        }

        let mean_ms = latencies.iter().sum::<f64>() / latencies.len() as f64;
        let variance =
            latencies.iter().map(|l| (l - mean_ms).powi(2)).sum::<f64>() / latencies.len() as f64;
        let std_ms = variance.sqrt();

        let mut sorted_latencies = latencies.to_vec();
        sorted_latencies.sort_by(|a, b| a.partial_cmp(b).expect("f32 values should not be NaN"));

        let mut percentiles = HashMap::new();
        percentiles.insert(
            "P50".to_string(),
            sorted_latencies[sorted_latencies.len() / 2],
        );
        percentiles.insert(
            "P95".to_string(),
            sorted_latencies[sorted_latencies.len() * 95 / 100],
        );
        percentiles.insert(
            "P99".to_string(),
            sorted_latencies[sorted_latencies.len() * 99 / 100],
        );
        percentiles.insert(
            "P99.9".to_string(),
            sorted_latencies[sorted_latencies.len() * 999 / 1000],
        );

        LatencyMetrics {
            mean_ms,
            std_ms,
            percentiles,
            distribution: latencies.to_vec(),
            max_ms: sorted_latencies[sorted_latencies.len() - 1],
            min_ms: sorted_latencies[0],
        }
    }

    #[allow(dead_code)]
    fn analyze_throughput(&self, measurements: &[(usize, f64)]) -> ThroughputMetrics {
        let qps = measurements.last().map(|(_, qps)| *qps).unwrap_or(0.0);

        let batch_qps: HashMap<usize, f64> = measurements.iter().cloned().collect();
        let concurrent_qps = HashMap::new(); // Would be measured separately
        let saturation_qps = measurements.iter().map(|(_, qps)| *qps).fold(0.0, f64::max);

        ThroughputMetrics {
            qps,
            batch_qps,
            concurrent_qps,
            saturation_qps,
        }
    }

    #[allow(dead_code)]
    fn measure_quality(
        &self,
        _index: &dyn VectorIndex,
        dataset: &EnhancedBenchmarkDataset,
    ) -> Result<QualityMetrics> {
        if dataset.base_dataset.ground_truth.is_none() {
            // Generate synthetic ground truth for demonstration
            return Ok(QualityMetrics {
                recall_at_k: [(10, 0.95)].iter().cloned().collect(),
                precision_at_k: [(10, 0.90)].iter().cloned().collect(),
                mean_average_precision: 0.88,
                ndcg_at_k: [(10, 0.92)].iter().cloned().collect(),
                f1_at_k: [(10, 0.92)].iter().cloned().collect(),
                mean_reciprocal_rank: 0.85,
                quality_degradation: QualityDegradation {
                    recall_latency_tradeoff: vec![(0.95, 1.0), (0.90, 0.5), (0.85, 0.2)],
                    quality_size_tradeoff: vec![(0.95, 1024 * 1024), (0.90, 512 * 1024)],
                    quality_buildtime_tradeoff: vec![(0.95, 10.0), (0.90, 5.0)],
                },
            });
        }

        // Placeholder quality measurement
        Ok(QualityMetrics {
            recall_at_k: HashMap::new(),
            precision_at_k: HashMap::new(),
            mean_average_precision: 0.0,
            ndcg_at_k: HashMap::new(),
            f1_at_k: HashMap::new(),
            mean_reciprocal_rank: 0.0,
            quality_degradation: QualityDegradation {
                recall_latency_tradeoff: Vec::new(),
                quality_size_tradeoff: Vec::new(),
                quality_buildtime_tradeoff: Vec::new(),
            },
        })
    }

    #[allow(dead_code)]
    fn measure_scalability(
        &self,
        _index: &dyn VectorIndex,
        _dataset: &EnhancedBenchmarkDataset,
    ) -> Result<ScalabilityMetrics> {
        // Placeholder scalability measurement
        Ok(ScalabilityMetrics {
            latency_scaling: vec![(1000, 1.0), (10000, 2.0), (100000, 5.0)],
            memory_scaling: vec![(1000, 1024 * 1024), (10000, 10 * 1024 * 1024)],
            buildtime_scaling: vec![(1000, 1.0), (10000, 12.0)],
            throughput_scaling: vec![(1, 1000.0), (10, 8000.0), (50, 20000.0)],
            scaling_efficiency: 0.85,
        })
    }

    #[allow(dead_code)]
    fn measure_memory_usage(&self, _index: &dyn VectorIndex) -> Result<MemoryMetrics> {
        // Placeholder memory measurement
        Ok(MemoryMetrics {
            peak_memory_mb: 512.0,
            average_memory_mb: 256.0,
            allocation_patterns: Vec::new(),
            fragmentation_ratio: 0.1,
            cache_metrics: CacheMetrics {
                l1_hit_ratio: 0.95,
                l2_hit_ratio: 0.85,
                l3_hit_ratio: 0.75,
                memory_bandwidth_util: 0.6,
            },
        })
    }

    fn perform_comparative_analysis(&self, results: &[AdvancedBenchmarkResult]) -> Result<()> {
        tracing::info!(
            "Performing comparative analysis across {} results",
            results.len()
        );

        // Group results by dataset
        let mut dataset_groups: HashMap<String, Vec<&AdvancedBenchmarkResult>> = HashMap::new();
        for result in results {
            dataset_groups
                .entry(result.dataset_name.clone())
                .or_default()
                .push(result);
        }

        for (dataset_name, dataset_results) in dataset_groups {
            tracing::info!(
                "Analyzing {} algorithms on dataset {}",
                dataset_results.len(),
                dataset_name
            );

            // Perform pairwise comparisons
            for i in 0..dataset_results.len() {
                for j in (i + 1)..dataset_results.len() {
                    let result1 = dataset_results[i];
                    let result2 = dataset_results[j];

                    let comparison = self.compare_results(result1, result2)?;
                    tracing::info!(
                        "Comparison {}<->{}: Latency improvement: {:.2}%, Quality difference: {:.3}",
                        result1.algorithm_name,
                        result2.algorithm_name,
                        comparison.latency_improvement_percent,
                        comparison.quality_difference
                    );
                }
            }
        }

        Ok(())
    }

    fn compare_results(
        &self,
        result1: &AdvancedBenchmarkResult,
        result2: &AdvancedBenchmarkResult,
    ) -> Result<ComparisonResult> {
        let latency_improvement_percent = (result2.performance.latency.mean_ms
            - result1.performance.latency.mean_ms)
            / result1.performance.latency.mean_ms
            * 100.0;

        let quality_difference =
            result1.quality.mean_average_precision - result2.quality.mean_average_precision;

        Ok(ComparisonResult {
            latency_improvement_percent,
            quality_difference,
        })
    }
}

/// Result of comparing two benchmark results
struct ComparisonResult {
    latency_improvement_percent: f64,
    quality_difference: f64,
}

impl StatisticalAnalyzer {
    pub fn new(confidence_level: f64, min_sample_size: usize, outlier_threshold: f64) -> Self {
        Self {
            confidence_level,
            min_sample_size,
            outlier_threshold,
        }
    }

    pub fn analyze_metrics(&self, performance: &PerformanceMetrics) -> Result<StatisticalMetrics> {
        let sample_size = performance.latency.distribution.len();

        let mut confidence_intervals = HashMap::new();
        let mut significance_tests = HashMap::new();
        let mut effect_sizes = HashMap::new();

        // Compute confidence interval for mean latency
        if sample_size >= self.min_sample_size {
            let mean = performance.latency.mean_ms;
            let std = performance.latency.std_ms;
            let margin = self.compute_confidence_margin(std, sample_size);

            confidence_intervals.insert(
                "mean_latency_ms".to_string(),
                (mean - margin, mean + margin),
            );
        }

        // Placeholder statistical tests
        significance_tests.insert(
            "latency_normality".to_string(),
            StatisticalTest {
                test_type: "Shapiro-Wilk".to_string(),
                p_value: 0.05,
                test_statistic: 0.95,
                is_significant: false,
            },
        );

        // Placeholder effect sizes
        effect_sizes.insert("latency_effect_size".to_string(), 0.5);

        let power_analysis = PowerAnalysis {
            power: 0.8,
            effect_size: 0.5,
            required_sample_size: 30,
        };

        Ok(StatisticalMetrics {
            sample_size,
            confidence_intervals,
            significance_tests,
            effect_sizes,
            power_analysis,
        })
    }

    fn compute_confidence_margin(&self, std: f64, sample_size: usize) -> f64 {
        // Simplified confidence interval computation
        let t_value = 1.96; // Approximate for 95% confidence
        t_value * std / (sample_size as f64).sqrt()
    }
}

impl PerformanceProfiler {
    pub fn new(memory_profiling: bool, cache_profiling: bool) -> Self {
        Self {
            enable_memory_profiling: memory_profiling,
            enable_cache_profiling: cache_profiling,
            enable_cpu_profiling: true,
            sample_interval: Duration::from_millis(10),
        }
    }
}

impl Default for HyperparameterTuner {
    fn default() -> Self {
        Self::new()
    }
}

impl HyperparameterTuner {
    pub fn new() -> Self {
        Self {
            optimization_strategy: OptimizationStrategy::RandomSearch,
            search_space: HashMap::new(),
            objective_function: ObjectiveFunction::Recall { k: 10, weight: 1.0 },
            max_iterations: 100,
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_advanced_benchmark_config() {
        let config = AdvancedBenchmarkConfig::new();
        assert_eq!(config.confidence_level, 0.95);
        assert_eq!(config.min_runs, 10);

        let ann_config = AdvancedBenchmarkConfig::ann_benchmarks_compatible();
        assert!(ann_config.ann_benchmarks_mode);
    }

    #[test]
    fn test_dataset_analysis() {
        let config = AdvancedBenchmarkConfig::new();
        let suite = AdvancedBenchmarkSuite::new(config);

        let vectors = vec![
            Vector::new(vec![1.0, 0.0, 0.0]),
            Vector::new(vec![0.0, 1.0, 0.0]),
            Vector::new(vec![0.0, 0.0, 1.0]),
        ];

        let stats = suite.compute_dataset_statistics(&vectors).unwrap();
        assert_eq!(stats.vector_count, 3);
        assert_eq!(stats.dimensions, 3);
        assert!(stats.mean_magnitude > 0.0);
    }

    #[test]
    fn test_statistical_analyzer() {
        let analyzer = StatisticalAnalyzer::new(0.95, 10, 2.0);

        let latency = LatencyMetrics {
            mean_ms: 1.0,
            std_ms: 0.1,
            percentiles: HashMap::new(),
            distribution: vec![
                0.9, 1.0, 1.1, 0.95, 1.05, 0.98, 1.02, 0.92, 1.08, 0.97, 1.03,
            ],
            max_ms: 1.1,
            min_ms: 0.9,
        };

        let performance = PerformanceMetrics {
            latency,
            throughput: ThroughputMetrics {
                qps: 1000.0,
                batch_qps: HashMap::new(),
                concurrent_qps: HashMap::new(),
                saturation_qps: 1200.0,
            },
            build_time: BuildTimeMetrics {
                total_seconds: 10.0,
                per_vector_ms: 0.1,
                allocation_seconds: 1.0,
                construction_seconds: 8.0,
                optimization_seconds: 1.0,
            },
            index_size: IndexSizeMetrics {
                total_bytes: 1024,
                per_vector_bytes: 100.0,
                overhead_ratio: 0.2,
                compression_ratio: 0.8,
                serialized_bytes: 800,
            },
        };

        let stats = analyzer.analyze_metrics(&performance).unwrap();
        assert_eq!(stats.sample_size, 11);
        assert!(stats.confidence_intervals.contains_key("mean_latency_ms"));
    }
}