quantrs2_circuit/
distributed.rs

1//! Distributed Circuit Execution Framework
2//!
3//! This module provides infrastructure for executing quantum circuits across
4//! multiple quantum devices, simulators, or cloud services in a distributed manner.
5
6use crate::builder::Circuit;
7use quantrs2_core::{
8    error::{QuantRS2Error, QuantRS2Result},
9    qubit::QubitId,
10};
11use scirs2_core::Complex64;
12use std::collections::HashMap;
13use std::time::{Duration, Instant};
14
15/// A distributed quantum circuit execution engine
16///
17/// This manages execution of quantum circuits across multiple backends,
18/// handling load balancing, fault tolerance, and result aggregation.
19#[derive(Debug)]
20pub struct DistributedExecutor {
21    /// Available execution backends
22    pub backends: Vec<ExecutionBackend>,
23    /// Load balancing strategy
24    pub load_balancer: LoadBalancer,
25    /// Fault tolerance configuration
26    pub fault_tolerance: FaultToleranceConfig,
27    /// Execution scheduling policy
28    pub scheduler: ExecutionScheduler,
29    /// Resource management
30    pub resource_manager: ResourceManager,
31}
32
33/// A quantum execution backend (device, simulator, or cloud service)
34#[derive(Debug, Clone)]
35pub struct ExecutionBackend {
36    /// Unique identifier for the backend
37    pub id: String,
38    /// Type of backend
39    pub backend_type: BackendType,
40    /// Current status
41    pub status: BackendStatus,
42    /// Performance characteristics
43    pub performance: BackendPerformance,
44    /// Queue information
45    pub queue_info: QueueInfo,
46    /// Supported operations
47    pub capabilities: BackendCapabilities,
48    /// Network configuration
49    pub network_config: NetworkConfig,
50}
51
52/// Types of quantum execution backends
53#[derive(Debug, Clone, PartialEq)]
54pub enum BackendType {
55    /// Physical quantum hardware
56    Hardware {
57        vendor: String,
58        model: String,
59        location: String,
60    },
61    /// Quantum simulator
62    Simulator {
63        simulator_type: SimulatorType,
64        host: String,
65    },
66    /// Cloud quantum service
67    CloudService {
68        provider: String,
69        service_name: String,
70        region: String,
71    },
72    /// Hybrid classical-quantum system
73    Hybrid {
74        quantum_backend: Box<Self>,
75        classical_resources: ClassicalResources,
76    },
77}
78
79/// Types of quantum simulators
80#[derive(Debug, Clone, PartialEq, Eq)]
81pub enum SimulatorType {
82    StateVector,
83    DensityMatrix,
84    TensorNetwork,
85    StabilunerformCode,
86    MatrixProductState,
87    Custom(String),
88}
89
90/// Classical computing resources for hybrid systems
91#[derive(Debug, Clone, PartialEq)]
92pub struct ClassicalResources {
93    /// CPU cores available
94    pub cpu_cores: usize,
95    /// Memory in GB
96    pub memory_gb: f64,
97    /// GPU information
98    pub gpus: Vec<GPUInfo>,
99    /// Storage capacity in GB
100    pub storage_gb: f64,
101}
102
103/// GPU information
104#[derive(Debug, Clone, PartialEq)]
105pub struct GPUInfo {
106    /// GPU model
107    pub model: String,
108    /// Memory in GB
109    pub memory_gb: f64,
110    /// Compute capability
111    pub compute_capability: String,
112}
113
114/// Current status of a backend
115#[derive(Debug, Clone, PartialEq, Eq)]
116pub enum BackendStatus {
117    /// Available for execution
118    Available,
119    /// Currently busy
120    Busy,
121    /// Temporarily unavailable
122    Unavailable,
123    /// Under maintenance
124    Maintenance,
125    /// Offline/disconnected
126    Offline,
127    /// Error state
128    Error(String),
129}
130
131/// Performance characteristics of a backend
132#[derive(Debug, Clone)]
133pub struct BackendPerformance {
134    /// Maximum number of qubits
135    pub max_qubits: usize,
136    /// Maximum circuit depth
137    pub max_depth: usize,
138    /// Gate fidelities
139    pub gate_fidelities: HashMap<String, f64>,
140    /// Coherence times (in microseconds)
141    pub coherence_times: HashMap<String, f64>,
142    /// Execution time estimates
143    pub execution_time_model: ExecutionTimeModel,
144    /// Throughput (circuits per second)
145    pub throughput: f64,
146}
147
148/// Model for predicting execution times
149#[derive(Debug, Clone)]
150pub struct ExecutionTimeModel {
151    /// Base execution time (seconds)
152    pub base_time: f64,
153    /// Time per gate (seconds)
154    pub time_per_gate: f64,
155    /// Time per qubit (seconds)
156    pub time_per_qubit: f64,
157    /// Time per measurement (seconds)
158    pub time_per_measurement: f64,
159    /// Network latency (seconds)
160    pub network_latency: f64,
161}
162
163/// Queue information for a backend
164#[derive(Debug, Clone)]
165pub struct QueueInfo {
166    /// Current queue length
167    pub queue_length: usize,
168    /// Estimated wait time (seconds)
169    pub estimated_wait_time: f64,
170    /// Maximum queue size
171    pub max_queue_size: usize,
172    /// Priority levels supported
173    pub priority_levels: Vec<Priority>,
174}
175
176/// Execution priority levels
177#[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
178pub enum Priority {
179    Low,
180    Normal,
181    High,
182    Critical,
183}
184
185/// Backend capabilities
186#[derive(Debug, Clone)]
187pub struct BackendCapabilities {
188    /// Supported gate set
189    pub supported_gates: Vec<String>,
190    /// Supports mid-circuit measurements
191    pub mid_circuit_measurements: bool,
192    /// Supports classical control flow
193    pub classical_control: bool,
194    /// Supports reset operations
195    pub reset_operations: bool,
196    /// Connectivity graph
197    pub connectivity: ConnectivityGraph,
198    /// Noise characteristics
199    pub noise_model: Option<NoiseCharacteristics>,
200}
201
202/// Qubit connectivity graph
203#[derive(Debug, Clone)]
204pub struct ConnectivityGraph {
205    /// Number of qubits
206    pub num_qubits: usize,
207    /// Edges representing allowed two-qubit gates
208    pub edges: Vec<(usize, usize)>,
209    /// Connectivity type
210    pub topology: TopologyType,
211}
212
213/// Types of qubit connectivity topologies
214#[derive(Debug, Clone, PartialEq)]
215pub enum TopologyType {
216    /// Linear chain
217    Linear,
218    /// 2D grid
219    Grid2D { rows: usize, cols: usize },
220    /// All-to-all connectivity
221    AllToAll,
222    /// Random graph
223    Random { density: f64 },
224    /// Custom topology
225    Custom,
226}
227
228/// Noise characteristics of a backend
229#[derive(Debug, Clone)]
230pub struct NoiseCharacteristics {
231    /// Single-qubit gate error rates
232    pub single_qubit_errors: HashMap<String, f64>,
233    /// Two-qubit gate error rates
234    pub two_qubit_errors: HashMap<String, f64>,
235    /// Measurement error rates
236    pub measurement_errors: Vec<f64>,
237    /// Decoherence times
238    pub decoherence_times: Vec<f64>,
239}
240
241/// Network configuration for backend communication
242#[derive(Debug, Clone)]
243pub struct NetworkConfig {
244    /// Endpoint URL
245    pub endpoint: String,
246    /// Authentication credentials
247    pub credentials: Credentials,
248    /// Timeout settings
249    pub timeouts: TimeoutConfig,
250    /// Retry policy
251    pub retry_policy: RetryPolicy,
252}
253
254/// Authentication credentials
255#[derive(Debug, Clone)]
256pub struct Credentials {
257    /// Authentication type
258    pub auth_type: AuthenticationType,
259    /// API key (if applicable)
260    pub api_key: Option<String>,
261    /// Token (if applicable)
262    pub token: Option<String>,
263    /// Username/password (if applicable)
264    pub username_password: Option<(String, String)>,
265}
266
267/// Types of authentication
268#[derive(Debug, Clone, PartialEq, Eq)]
269pub enum AuthenticationType {
270    ApiKey,
271    Token,
272    UsernamePassword,
273    Certificate,
274    None,
275}
276
277/// Timeout configuration
278#[derive(Debug, Clone)]
279pub struct TimeoutConfig {
280    /// Connection timeout (seconds)
281    pub connection_timeout: f64,
282    /// Request timeout (seconds)
283    pub request_timeout: f64,
284    /// Total timeout (seconds)
285    pub total_timeout: f64,
286}
287
288/// Retry policy configuration
289#[derive(Debug, Clone)]
290pub struct RetryPolicy {
291    /// Maximum number of retries
292    pub max_retries: usize,
293    /// Base delay between retries (seconds)
294    pub base_delay: f64,
295    /// Backoff strategy
296    pub backoff_strategy: BackoffStrategy,
297    /// Retryable error types
298    pub retryable_errors: Vec<ErrorType>,
299}
300
301/// Backoff strategies for retries
302#[derive(Debug, Clone, PartialEq)]
303pub enum BackoffStrategy {
304    /// Fixed delay
305    Fixed,
306    /// Linear backoff
307    Linear,
308    /// Exponential backoff
309    Exponential { multiplier: f64 },
310    /// Random jitter
311    Jitter { max_jitter: f64 },
312}
313
314/// Types of errors that can be retried
315#[derive(Debug, Clone, PartialEq, Eq)]
316pub enum ErrorType {
317    NetworkError,
318    TimeoutError,
319    ServiceUnavailable,
320    RateLimited,
321    InternalServerError,
322}
323
324/// Load balancing strategies
325#[derive(Debug, Clone)]
326pub struct LoadBalancer {
327    /// Balancing strategy
328    pub strategy: LoadBalancingStrategy,
329    /// Health check configuration
330    pub health_check: HealthCheckConfig,
331    /// Metrics collection
332    pub metrics: MetricsConfig,
333}
334
335/// Load balancing strategies
336#[derive(Debug, Clone, PartialEq)]
337pub enum LoadBalancingStrategy {
338    /// Round robin
339    RoundRobin,
340    /// Least connections
341    LeastConnections,
342    /// Least queue time
343    LeastQueueTime,
344    /// Best performance
345    BestPerformance,
346    /// Weighted round robin
347    WeightedRoundRobin(HashMap<String, f64>),
348    /// Custom strategy
349    Custom(String),
350}
351
352/// Health check configuration
353#[derive(Debug, Clone)]
354pub struct HealthCheckConfig {
355    /// Health check interval (seconds)
356    pub interval: f64,
357    /// Health check timeout (seconds)
358    pub timeout: f64,
359    /// Number of failed checks before marking unhealthy
360    pub failure_threshold: usize,
361    /// Number of successful checks before marking healthy
362    pub success_threshold: usize,
363}
364
365/// Metrics collection configuration
366#[derive(Debug, Clone)]
367pub struct MetricsConfig {
368    /// Enable metrics collection
369    pub enabled: bool,
370    /// Metrics collection interval (seconds)
371    pub collection_interval: f64,
372    /// Metrics retention period (seconds)
373    pub retention_period: f64,
374    /// Metrics storage backend
375    pub storage_backend: MetricsStorage,
376}
377
378/// Metrics storage backends
379#[derive(Debug, Clone, PartialEq, Eq)]
380pub enum MetricsStorage {
381    InMemory,
382    File(String),
383    Database(String),
384    CloudStorage(String),
385}
386
387/// Fault tolerance configuration
388#[derive(Debug, Clone)]
389pub struct FaultToleranceConfig {
390    /// Enable automatic failover
391    pub enable_failover: bool,
392    /// Circuit redundancy level
393    pub redundancy_level: usize,
394    /// Error correction strategy
395    pub error_correction: ErrorCorrectionStrategy,
396    /// Failure detection configuration
397    pub failure_detection: FailureDetectionConfig,
398}
399
400/// Error correction strategies
401#[derive(Debug, Clone, PartialEq, Eq)]
402pub enum ErrorCorrectionStrategy {
403    /// No error correction
404    None,
405    /// Majority voting
406    MajorityVoting,
407    /// Quantum error correction
408    QuantumErrorCorrection,
409    /// Classical post-processing
410    ClassicalPostProcessing,
411    /// Custom strategy
412    Custom(String),
413}
414
415/// Failure detection configuration
416#[derive(Debug, Clone)]
417pub struct FailureDetectionConfig {
418    /// Detection methods
419    pub detection_methods: Vec<FailureDetectionMethod>,
420    /// Detection threshold
421    pub detection_threshold: f64,
422    /// Detection window (seconds)
423    pub detection_window: f64,
424}
425
426/// Failure detection methods
427#[derive(Debug, Clone, PartialEq, Eq)]
428pub enum FailureDetectionMethod {
429    /// Error rate monitoring
430    ErrorRateMonitoring,
431    /// Latency monitoring
432    LatencyMonitoring,
433    /// Result validation
434    ResultValidation,
435    /// Health check failures
436    HealthCheckFailures,
437}
438
439/// Execution scheduler
440#[derive(Debug, Clone)]
441pub struct ExecutionScheduler {
442    /// Scheduling policy
443    pub policy: SchedulingPolicy,
444    /// Priority queue configuration
445    pub priority_queue: PriorityQueueConfig,
446    /// Resource allocation strategy
447    pub resource_allocation: ResourceAllocationStrategy,
448}
449
450/// Scheduling policies
451#[derive(Debug, Clone, PartialEq, Eq)]
452pub enum SchedulingPolicy {
453    /// First-come, first-served
454    FCFS,
455    /// Shortest job first
456    SJF,
457    /// Priority-based scheduling
458    Priority,
459    /// Fair share scheduling
460    FairShare,
461    /// Deadline-aware scheduling
462    DeadlineAware,
463    /// Custom policy
464    Custom(String),
465}
466
467/// Priority queue configuration
468#[derive(Debug, Clone)]
469pub struct PriorityQueueConfig {
470    /// Maximum queue size per priority
471    pub max_size_per_priority: HashMap<Priority, usize>,
472    /// Aging factor for priority adjustment
473    pub aging_factor: f64,
474    /// Priority boost interval (seconds)
475    pub priority_boost_interval: f64,
476}
477
478/// Resource allocation strategies
479#[derive(Debug, Clone, PartialEq, Eq)]
480pub enum ResourceAllocationStrategy {
481    /// Best fit
482    BestFit,
483    /// First fit
484    FirstFit,
485    /// Worst fit
486    WorstFit,
487    /// Next fit
488    NextFit,
489    /// Custom allocation
490    Custom(String),
491}
492
493/// Resource manager
494#[derive(Debug, Clone)]
495pub struct ResourceManager {
496    /// Resource pool
497    pub resource_pool: ResourcePool,
498    /// Allocation policies
499    pub allocation_policies: AllocationPolicies,
500    /// Usage tracking
501    pub usage_tracking: UsageTracking,
502}
503
504/// Resource pool information
505#[derive(Debug, Clone)]
506pub struct ResourcePool {
507    /// Total available qubits across all backends
508    pub total_qubits: usize,
509    /// Available execution slots
510    pub available_slots: usize,
511    /// Memory pool (in GB)
512    pub memory_pool: f64,
513    /// Compute pool (in CPU hours)
514    pub compute_pool: f64,
515}
516
517/// Resource allocation policies
518#[derive(Debug, Clone)]
519pub struct AllocationPolicies {
520    /// Maximum qubits per user
521    pub max_qubits_per_user: Option<usize>,
522    /// Maximum execution time per job
523    pub max_execution_time: Option<f64>,
524    /// Fair share allocation
525    pub fair_share: bool,
526    /// Reserved resources for high-priority jobs
527    pub reserved_resources: f64,
528}
529
530/// Usage tracking configuration
531#[derive(Debug, Clone)]
532pub struct UsageTracking {
533    /// Track per-user usage
534    pub per_user_tracking: bool,
535    /// Track per-project usage
536    pub per_project_tracking: bool,
537    /// Usage reporting interval (seconds)
538    pub reporting_interval: f64,
539    /// Usage data retention (seconds)
540    pub retention_period: f64,
541}
542
543/// Distributed execution job
544#[derive(Debug, Clone)]
545pub struct DistributedJob<const N: usize> {
546    /// Job identifier
547    pub id: String,
548    /// Circuit to execute
549    pub circuit: Circuit<N>,
550    /// Execution parameters
551    pub parameters: ExecutionParameters,
552    /// Job priority
553    pub priority: Priority,
554    /// Target backends (if specified)
555    pub target_backends: Option<Vec<String>>,
556    /// Submission time
557    pub submitted_at: Instant,
558    /// Deadline (if any)
559    pub deadline: Option<Instant>,
560}
561
562/// Execution parameters for a job
563#[derive(Debug, Clone)]
564pub struct ExecutionParameters {
565    /// Number of shots
566    pub shots: usize,
567    /// Optimization level
568    pub optimization_level: usize,
569    /// Error mitigation techniques
570    pub error_mitigation: Vec<ErrorMitigation>,
571    /// Result format
572    pub result_format: ResultFormat,
573    /// Memory requirements
574    pub memory_requirement: Option<f64>,
575}
576
577/// Error mitigation techniques
578#[derive(Debug, Clone, PartialEq, Eq)]
579pub enum ErrorMitigation {
580    /// Readout error mitigation
581    ReadoutErrorMitigation,
582    /// Zero-noise extrapolation
583    ZeroNoiseExtrapolation,
584    /// Clifford data regression
585    CliffordDataRegression,
586    /// Symmetry verification
587    SymmetryVerification,
588    /// Custom mitigation
589    Custom(String),
590}
591
592/// Result format options
593#[derive(Debug, Clone, PartialEq, Eq)]
594pub enum ResultFormat {
595    /// Raw counts
596    Counts,
597    /// Probabilities
598    Probabilities,
599    /// Statevector (if available)
600    Statevector,
601    /// Expectation values
602    ExpectationValues,
603    /// Custom format
604    Custom(String),
605}
606
607/// Execution result from distributed system
608#[derive(Debug, Clone)]
609pub struct DistributedResult {
610    /// Job ID
611    pub job_id: String,
612    /// Execution status
613    pub status: ExecutionStatus,
614    /// Results from each backend
615    pub backend_results: HashMap<String, BackendResult>,
616    /// Aggregated final result
617    pub final_result: Option<AggregatedResult>,
618    /// Execution metadata
619    pub metadata: ExecutionMetadata,
620}
621
622/// Execution status
623#[derive(Debug, Clone, PartialEq, Eq)]
624pub enum ExecutionStatus {
625    /// Job queued
626    Queued,
627    /// Job running
628    Running,
629    /// Job completed successfully
630    Completed,
631    /// Job failed
632    Failed(String),
633    /// Job cancelled
634    Cancelled,
635    /// Job timed out
636    TimedOut,
637}
638
639/// Result from a single backend
640#[derive(Debug, Clone)]
641pub struct BackendResult {
642    /// Backend ID
643    pub backend_id: String,
644    /// Execution status on this backend
645    pub status: ExecutionStatus,
646    /// Raw measurement results
647    pub measurements: Option<Vec<Vec<bool>>>,
648    /// Probability distributions
649    pub probabilities: Option<HashMap<String, f64>>,
650    /// Execution time
651    pub execution_time: Duration,
652    /// Error information (if any)
653    pub error: Option<String>,
654}
655
656/// Aggregated result across multiple backends
657#[derive(Debug, Clone)]
658pub struct AggregatedResult {
659    /// Combined measurement statistics
660    pub combined_measurements: HashMap<String, f64>,
661    /// Error estimates
662    pub error_estimates: HashMap<String, f64>,
663    /// Confidence intervals
664    pub confidence_intervals: HashMap<String, (f64, f64)>,
665    /// Quality metrics
666    pub quality_metrics: QualityMetrics,
667}
668
669/// Quality metrics for results
670#[derive(Debug, Clone)]
671pub struct QualityMetrics {
672    /// Statistical significance
673    pub statistical_significance: f64,
674    /// Consistency across backends
675    pub consistency_score: f64,
676    /// Estimated fidelity
677    pub estimated_fidelity: f64,
678    /// Error mitigation effectiveness
679    pub mitigation_effectiveness: f64,
680}
681
682/// Execution metadata
683#[derive(Debug, Clone)]
684pub struct ExecutionMetadata {
685    /// Total execution time
686    pub total_time: Duration,
687    /// Queue wait time
688    pub queue_time: Duration,
689    /// Backends used
690    pub backends_used: Vec<String>,
691    /// Resource usage
692    pub resource_usage: ResourceUsage,
693    /// Cost information
694    pub cost_info: Option<CostInfo>,
695}
696
697/// Resource usage information
698#[derive(Debug, Clone)]
699pub struct ResourceUsage {
700    /// CPU hours used
701    pub cpu_hours: f64,
702    /// Memory-hours used
703    pub memory_hours: f64,
704    /// Qubit-hours used
705    pub qubit_hours: f64,
706    /// Network bandwidth used (GB)
707    pub network_usage: f64,
708}
709
710/// Cost information
711#[derive(Debug, Clone)]
712pub struct CostInfo {
713    /// Total cost
714    pub total_cost: f64,
715    /// Cost breakdown by resource
716    pub cost_breakdown: HashMap<String, f64>,
717    /// Currency
718    pub currency: String,
719}
720
721impl DistributedExecutor {
722    /// Create a new distributed executor
723    #[must_use]
724    pub fn new() -> Self {
725        Self {
726            backends: Vec::new(),
727            load_balancer: LoadBalancer {
728                strategy: LoadBalancingStrategy::RoundRobin,
729                health_check: HealthCheckConfig {
730                    interval: 30.0,
731                    timeout: 5.0,
732                    failure_threshold: 3,
733                    success_threshold: 2,
734                },
735                metrics: MetricsConfig {
736                    enabled: true,
737                    collection_interval: 60.0,
738                    retention_period: 3600.0 * 24.0, // 24 hours
739                    storage_backend: MetricsStorage::InMemory,
740                },
741            },
742            fault_tolerance: FaultToleranceConfig {
743                enable_failover: true,
744                redundancy_level: 1,
745                error_correction: ErrorCorrectionStrategy::MajorityVoting,
746                failure_detection: FailureDetectionConfig {
747                    detection_methods: vec![
748                        FailureDetectionMethod::ErrorRateMonitoring,
749                        FailureDetectionMethod::LatencyMonitoring,
750                    ],
751                    detection_threshold: 0.1,
752                    detection_window: 300.0,
753                },
754            },
755            scheduler: ExecutionScheduler {
756                policy: SchedulingPolicy::Priority,
757                priority_queue: PriorityQueueConfig {
758                    max_size_per_priority: {
759                        let mut map = HashMap::new();
760                        map.insert(Priority::Critical, 10);
761                        map.insert(Priority::High, 50);
762                        map.insert(Priority::Normal, 200);
763                        map.insert(Priority::Low, 1000);
764                        map
765                    },
766                    aging_factor: 0.1,
767                    priority_boost_interval: 3600.0, // 1 hour
768                },
769                resource_allocation: ResourceAllocationStrategy::BestFit,
770            },
771            resource_manager: ResourceManager {
772                resource_pool: ResourcePool {
773                    total_qubits: 0,
774                    available_slots: 0,
775                    memory_pool: 0.0,
776                    compute_pool: 0.0,
777                },
778                allocation_policies: AllocationPolicies {
779                    max_qubits_per_user: Some(100),
780                    max_execution_time: Some(3600.0), // 1 hour
781                    fair_share: true,
782                    reserved_resources: 0.1, // 10% reserved
783                },
784                usage_tracking: UsageTracking {
785                    per_user_tracking: true,
786                    per_project_tracking: true,
787                    reporting_interval: 3600.0,             // 1 hour
788                    retention_period: 3600.0 * 24.0 * 30.0, // 30 days
789                },
790            },
791        }
792    }
793
794    /// Add a backend to the distributed executor
795    pub fn add_backend(&mut self, backend: ExecutionBackend) -> QuantRS2Result<()> {
796        // Validate backend configuration
797        if backend.id.is_empty() {
798            return Err(QuantRS2Error::InvalidInput(
799                "Backend ID cannot be empty".to_string(),
800            ));
801        }
802
803        // Check for duplicate IDs
804        if self.backends.iter().any(|b| b.id == backend.id) {
805            return Err(QuantRS2Error::InvalidInput(format!(
806                "Backend with ID '{}' already exists",
807                backend.id
808            )));
809        }
810
811        // Update resource pool
812        self.resource_manager.resource_pool.total_qubits += backend.performance.max_qubits;
813        self.resource_manager.resource_pool.available_slots += 1;
814
815        self.backends.push(backend);
816        Ok(())
817    }
818
819    /// Submit a job for distributed execution
820    pub fn submit_job<const N: usize>(&mut self, job: DistributedJob<N>) -> QuantRS2Result<String> {
821        // Validate job
822        if job.circuit.num_gates() == 0 {
823            return Err(QuantRS2Error::InvalidInput(
824                "Cannot submit empty circuit".to_string(),
825            ));
826        }
827
828        // Check resource requirements
829        let required_qubits = job.circuit.num_qubits();
830        if required_qubits > self.resource_manager.resource_pool.total_qubits {
831            return Err(QuantRS2Error::UnsupportedQubits(
832                required_qubits,
833                format!(
834                    "Maximum available qubits: {}",
835                    self.resource_manager.resource_pool.total_qubits
836                ),
837            ));
838        }
839
840        // Select appropriate backends
841        let selected_backends = self.select_backends(&job)?;
842        if selected_backends.is_empty() {
843            return Err(QuantRS2Error::BackendExecutionFailed(
844                "No suitable backends available".to_string(),
845            ));
846        }
847
848        // This is a placeholder for job submission
849        // In a real implementation, this would:
850        // 1. Queue the job according to scheduling policy
851        // 2. Allocate resources
852        // 3. Distribute execution across selected backends
853        // 4. Set up monitoring and fault tolerance
854
855        Ok(job.id)
856    }
857
858    /// Select appropriate backends for a job
859    fn select_backends<const N: usize>(
860        &self,
861        job: &DistributedJob<N>,
862    ) -> QuantRS2Result<Vec<String>> {
863        let mut suitable_backends = Vec::new();
864
865        for backend in &self.backends {
866            if self.is_backend_suitable(backend, job) {
867                suitable_backends.push(backend.id.clone());
868            }
869        }
870
871        // Apply load balancing strategy
872        match self.load_balancer.strategy {
873            LoadBalancingStrategy::RoundRobin => {
874                // Simple round-robin selection
875                suitable_backends.truncate(self.fault_tolerance.redundancy_level.max(1));
876            }
877            LoadBalancingStrategy::LeastQueueTime => {
878                // Sort by queue time
879                suitable_backends.sort_by(|a, b| {
880                    let backend_a = self
881                        .backends
882                        .iter()
883                        .find(|backend| backend.id == *a)
884                        .expect("Backend ID in suitable_backends must exist in backends list");
885                    let backend_b = self
886                        .backends
887                        .iter()
888                        .find(|backend| backend.id == *b)
889                        .expect("Backend ID in suitable_backends must exist in backends list");
890                    backend_a
891                        .queue_info
892                        .estimated_wait_time
893                        .partial_cmp(&backend_b.queue_info.estimated_wait_time)
894                        .unwrap_or(std::cmp::Ordering::Equal)
895                });
896                suitable_backends.truncate(self.fault_tolerance.redundancy_level.max(1));
897            }
898            _ => {
899                // Default to first available
900                suitable_backends.truncate(1);
901            }
902        }
903
904        Ok(suitable_backends)
905    }
906
907    /// Check if a backend is suitable for a job
908    fn is_backend_suitable<const N: usize>(
909        &self,
910        backend: &ExecutionBackend,
911        job: &DistributedJob<N>,
912    ) -> bool {
913        // Check status
914        if backend.status != BackendStatus::Available {
915            return false;
916        }
917
918        // Check qubit requirements
919        if job.circuit.num_qubits() > backend.performance.max_qubits {
920            return false;
921        }
922
923        // Check circuit depth
924        if job.circuit.num_gates() > backend.performance.max_depth {
925            return false;
926        }
927
928        // Check target backends (if specified)
929        if let Some(ref targets) = job.target_backends {
930            if !targets.contains(&backend.id) {
931                return false;
932            }
933        }
934
935        // Check queue capacity
936        if backend.queue_info.queue_length >= backend.queue_info.max_queue_size {
937            return false;
938        }
939
940        true
941    }
942
943    /// Get execution status for a job
944    pub const fn get_job_status(&self, job_id: &str) -> QuantRS2Result<ExecutionStatus> {
945        // This is a placeholder - real implementation would track job status
946        Ok(ExecutionStatus::Queued)
947    }
948
949    /// Cancel a job
950    pub const fn cancel_job(&mut self, job_id: &str) -> QuantRS2Result<()> {
951        // This is a placeholder - real implementation would cancel the job
952        // across all backends and clean up resources
953        Ok(())
954    }
955
956    /// Get results for a completed job
957    pub fn get_results(&self, job_id: &str) -> QuantRS2Result<DistributedResult> {
958        // This is a placeholder - real implementation would aggregate
959        // results from all backends and apply error correction
960        Ok(DistributedResult {
961            job_id: job_id.to_string(),
962            status: ExecutionStatus::Completed,
963            backend_results: HashMap::new(),
964            final_result: None,
965            metadata: ExecutionMetadata {
966                total_time: Duration::from_secs(1),
967                queue_time: Duration::from_secs(0),
968                backends_used: vec!["backend_1".to_string()],
969                resource_usage: ResourceUsage {
970                    cpu_hours: 0.1,
971                    memory_hours: 0.1,
972                    qubit_hours: 0.1,
973                    network_usage: 0.01,
974                },
975                cost_info: None,
976            },
977        })
978    }
979
980    /// Get system health status
981    #[must_use]
982    pub fn get_health_status(&self) -> SystemHealthStatus {
983        let available_backends = self
984            .backends
985            .iter()
986            .filter(|b| b.status == BackendStatus::Available)
987            .count();
988
989        let total_qubits = self
990            .backends
991            .iter()
992            .filter(|b| b.status == BackendStatus::Available)
993            .map(|b| b.performance.max_qubits)
994            .sum();
995
996        SystemHealthStatus {
997            total_backends: self.backends.len(),
998            available_backends,
999            total_qubits,
1000            average_queue_time: self
1001                .backends
1002                .iter()
1003                .map(|b| b.queue_info.estimated_wait_time)
1004                .sum::<f64>()
1005                / self.backends.len() as f64,
1006            system_load: self.calculate_system_load(),
1007        }
1008    }
1009
1010    /// Calculate overall system load
1011    fn calculate_system_load(&self) -> f64 {
1012        if self.backends.is_empty() {
1013            return 0.0;
1014        }
1015
1016        let total_capacity: f64 = self
1017            .backends
1018            .iter()
1019            .map(|b| b.queue_info.max_queue_size as f64)
1020            .sum();
1021
1022        let current_load: f64 = self
1023            .backends
1024            .iter()
1025            .map(|b| b.queue_info.queue_length as f64)
1026            .sum();
1027
1028        if total_capacity > 0.0 {
1029            current_load / total_capacity
1030        } else {
1031            0.0
1032        }
1033    }
1034}
1035
1036/// System health status
1037#[derive(Debug, Clone)]
1038pub struct SystemHealthStatus {
1039    /// Total number of backends
1040    pub total_backends: usize,
1041    /// Number of available backends
1042    pub available_backends: usize,
1043    /// Total available qubits
1044    pub total_qubits: usize,
1045    /// Average queue time across all backends
1046    pub average_queue_time: f64,
1047    /// Overall system load (0.0 to 1.0)
1048    pub system_load: f64,
1049}
1050
1051impl Default for DistributedExecutor {
1052    fn default() -> Self {
1053        Self::new()
1054    }
1055}
1056
1057#[cfg(test)]
1058mod tests {
1059    use super::*;
1060
1061    #[test]
1062    fn test_distributed_executor_creation() {
1063        let executor = DistributedExecutor::new();
1064        assert_eq!(executor.backends.len(), 0);
1065        assert_eq!(executor.resource_manager.resource_pool.total_qubits, 0);
1066    }
1067
1068    #[test]
1069    fn test_backend_addition() {
1070        let mut executor = DistributedExecutor::new();
1071
1072        let backend = ExecutionBackend {
1073            id: "test_backend".to_string(),
1074            backend_type: BackendType::Simulator {
1075                simulator_type: SimulatorType::StateVector,
1076                host: "localhost".to_string(),
1077            },
1078            status: BackendStatus::Available,
1079            performance: BackendPerformance {
1080                max_qubits: 10,
1081                max_depth: 1000,
1082                gate_fidelities: HashMap::new(),
1083                coherence_times: HashMap::new(),
1084                execution_time_model: ExecutionTimeModel {
1085                    base_time: 0.1,
1086                    time_per_gate: 0.001,
1087                    time_per_qubit: 0.01,
1088                    time_per_measurement: 0.005,
1089                    network_latency: 0.05,
1090                },
1091                throughput: 10.0,
1092            },
1093            queue_info: QueueInfo {
1094                queue_length: 0,
1095                estimated_wait_time: 0.0,
1096                max_queue_size: 100,
1097                priority_levels: vec![Priority::Normal, Priority::High],
1098            },
1099            capabilities: BackendCapabilities {
1100                supported_gates: vec!["h".to_string(), "cnot".to_string()],
1101                mid_circuit_measurements: false,
1102                classical_control: false,
1103                reset_operations: false,
1104                connectivity: ConnectivityGraph {
1105                    num_qubits: 10,
1106                    edges: vec![(0, 1), (1, 2)],
1107                    topology: TopologyType::Linear,
1108                },
1109                noise_model: None,
1110            },
1111            network_config: NetworkConfig {
1112                endpoint: "http://localhost:8080".to_string(),
1113                credentials: Credentials {
1114                    auth_type: AuthenticationType::None,
1115                    api_key: None,
1116                    token: None,
1117                    username_password: None,
1118                },
1119                timeouts: TimeoutConfig {
1120                    connection_timeout: 5.0,
1121                    request_timeout: 30.0,
1122                    total_timeout: 60.0,
1123                },
1124                retry_policy: RetryPolicy {
1125                    max_retries: 3,
1126                    base_delay: 1.0,
1127                    backoff_strategy: BackoffStrategy::Exponential { multiplier: 2.0 },
1128                    retryable_errors: vec![ErrorType::NetworkError, ErrorType::TimeoutError],
1129                },
1130            },
1131        };
1132
1133        executor
1134            .add_backend(backend)
1135            .expect("Failed to add backend to executor");
1136        assert_eq!(executor.backends.len(), 1);
1137        assert_eq!(executor.resource_manager.resource_pool.total_qubits, 10);
1138    }
1139
1140    #[test]
1141    fn test_job_submission() {
1142        let mut executor = DistributedExecutor::new();
1143
1144        // Add a backend first
1145        let backend = create_test_backend();
1146        executor
1147            .add_backend(backend)
1148            .expect("Failed to add backend to executor");
1149
1150        // Create a test job
1151        let mut circuit = Circuit::<2>::new();
1152        circuit.h(QubitId(0)).expect("Failed to add Hadamard gate"); // Add a gate so it's not empty
1153        let job = DistributedJob {
1154            id: "test_job".to_string(),
1155            circuit,
1156            parameters: ExecutionParameters {
1157                shots: 1000,
1158                optimization_level: 1,
1159                error_mitigation: vec![],
1160                result_format: ResultFormat::Counts,
1161                memory_requirement: None,
1162            },
1163            priority: Priority::Normal,
1164            target_backends: None,
1165            submitted_at: Instant::now(),
1166            deadline: None,
1167        };
1168
1169        let job_id = executor
1170            .submit_job(job)
1171            .expect("Failed to submit job to executor");
1172        assert_eq!(job_id, "test_job");
1173    }
1174
1175    fn create_test_backend() -> ExecutionBackend {
1176        ExecutionBackend {
1177            id: "test_backend".to_string(),
1178            backend_type: BackendType::Simulator {
1179                simulator_type: SimulatorType::StateVector,
1180                host: "localhost".to_string(),
1181            },
1182            status: BackendStatus::Available,
1183            performance: BackendPerformance {
1184                max_qubits: 10,
1185                max_depth: 1000,
1186                gate_fidelities: HashMap::new(),
1187                coherence_times: HashMap::new(),
1188                execution_time_model: ExecutionTimeModel {
1189                    base_time: 0.1,
1190                    time_per_gate: 0.001,
1191                    time_per_qubit: 0.01,
1192                    time_per_measurement: 0.005,
1193                    network_latency: 0.05,
1194                },
1195                throughput: 10.0,
1196            },
1197            queue_info: QueueInfo {
1198                queue_length: 0,
1199                estimated_wait_time: 0.0,
1200                max_queue_size: 100,
1201                priority_levels: vec![Priority::Normal, Priority::High],
1202            },
1203            capabilities: BackendCapabilities {
1204                supported_gates: vec!["h".to_string(), "cnot".to_string()],
1205                mid_circuit_measurements: false,
1206                classical_control: false,
1207                reset_operations: false,
1208                connectivity: ConnectivityGraph {
1209                    num_qubits: 10,
1210                    edges: vec![(0, 1), (1, 2)],
1211                    topology: TopologyType::Linear,
1212                },
1213                noise_model: None,
1214            },
1215            network_config: NetworkConfig {
1216                endpoint: "http://localhost:8080".to_string(),
1217                credentials: Credentials {
1218                    auth_type: AuthenticationType::None,
1219                    api_key: None,
1220                    token: None,
1221                    username_password: None,
1222                },
1223                timeouts: TimeoutConfig {
1224                    connection_timeout: 5.0,
1225                    request_timeout: 30.0,
1226                    total_timeout: 60.0,
1227                },
1228                retry_policy: RetryPolicy {
1229                    max_retries: 3,
1230                    base_delay: 1.0,
1231                    backoff_strategy: BackoffStrategy::Exponential { multiplier: 2.0 },
1232                    retryable_errors: vec![ErrorType::NetworkError, ErrorType::TimeoutError],
1233                },
1234            },
1235        }
1236    }
1237}
quantrs2_circuit/distributed.rs

quantrs2_circuit/
distributed.rs
