quantrs2_device/
translation.rs

1//! Gate translation for different hardware backends
2//!
3//! This module provides comprehensive gate translation capabilities, converting
4//! gates between different hardware native gate sets and decomposing complex
5//! gates into hardware-supported operations.
6
7use scirs2_core::ndarray::Array2;
8use scirs2_core::Complex64;
9use serde::{Deserialize, Serialize};
10use std::collections::HashMap;
11use std::f64::consts::PI;
12
13use quantrs2_circuit::builder::Circuit;
14use quantrs2_core::{
15    error::{QuantRS2Error, QuantRS2Result},
16    gate::{multi::*, single::*, GateOp},
17    qubit::QubitId,
18    synthesis::{decompose_single_qubit_zyz, decompose_two_qubit_kak},
19};
20
21/// Hardware backend types
22#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash, serde::Serialize, serde::Deserialize)]
23pub enum HardwareBackend {
24    /// IBM Quantum devices
25    IBMQuantum,
26    /// Google Quantum devices
27    GoogleSycamore,
28    /// IonQ trapped ion devices
29    IonQ,
30    /// Rigetti quantum devices
31    Rigetti,
32    /// Amazon Braket devices
33    AmazonBraket,
34    /// Azure Quantum devices
35    AzureQuantum,
36    /// Honeywell/Quantinuum devices
37    Honeywell,
38    /// Generic/Custom backend
39    Custom(u32), // Custom ID
40}
41
42/// Native gate set for a hardware backend
43#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
44pub struct NativeGateSet {
45    /// Backend type
46    pub backend: HardwareBackend,
47    /// Single-qubit gates supported
48    pub single_qubit_gates: Vec<String>,
49    /// Two-qubit gates supported
50    pub two_qubit_gates: Vec<String>,
51    /// Multi-qubit gates supported (if any)
52    pub multi_qubit_gates: Vec<String>,
53    /// Whether arbitrary single-qubit rotations are supported
54    pub arbitrary_single_qubit: bool,
55    /// Supported rotation axes for parameterized gates
56    pub rotation_axes: Vec<RotationAxis>,
57    /// Additional backend-specific constraints
58    pub constraints: BackendConstraints,
59}
60
61impl Default for NativeGateSet {
62    fn default() -> Self {
63        Self {
64            backend: HardwareBackend::Custom(0),
65            single_qubit_gates: vec![
66                "H".to_string(),
67                "X".to_string(),
68                "Y".to_string(),
69                "Z".to_string(),
70            ],
71            two_qubit_gates: vec!["CNOT".to_string(), "CZ".to_string()],
72            multi_qubit_gates: Vec::new(),
73            arbitrary_single_qubit: true,
74            rotation_axes: vec![RotationAxis::X, RotationAxis::Y, RotationAxis::Z],
75            constraints: BackendConstraints::default(),
76        }
77    }
78}
79
80/// Rotation axes supported by hardware
81#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
82pub enum RotationAxis {
83    X,
84    Y,
85    Z,
86    XY(f64),               // Rotation in X-Y plane at angle
87    Custom(f64, f64, f64), // Arbitrary axis (x, y, z)
88}
89
90/// Backend-specific constraints
91#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
92pub struct BackendConstraints {
93    /// Maximum circuit depth
94    pub max_depth: Option<usize>,
95    /// Supported angles for rotation gates (None = continuous)
96    pub discrete_angles: Option<Vec<f64>>,
97    /// Whether phase gates are virtual (frame changes)
98    pub virtual_z: bool,
99    /// Coupling constraints (for 2-qubit gates)
100    pub coupling_map: Option<Vec<(usize, usize)>>,
101    /// Gate timing constraints
102    pub timing_constraints: Option<TimingConstraints>,
103}
104
105impl Default for BackendConstraints {
106    fn default() -> Self {
107        Self {
108            max_depth: None,
109            discrete_angles: None,
110            virtual_z: false,
111            coupling_map: None,
112            timing_constraints: None,
113        }
114    }
115}
116
117/// Timing constraints for hardware
118#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
119pub struct TimingConstraints {
120    /// Minimum time between gates on same qubit (ns)
121    pub min_gate_spacing: f64,
122    /// Required alignment for gate start times
123    pub time_alignment: f64,
124    /// Maximum circuit duration (ns)
125    pub max_duration: Option<f64>,
126}
127
128impl Default for TimingConstraints {
129    fn default() -> Self {
130        Self {
131            min_gate_spacing: 0.0,
132            time_alignment: 1.0,
133            max_duration: None,
134        }
135    }
136}
137
138/// Gate translator for converting between gate sets
139pub struct GateTranslator {
140    /// Native gate sets for each backend
141    native_gates: HashMap<HardwareBackend, NativeGateSet>,
142    /// Translation rules
143    translation_rules: HashMap<(HardwareBackend, String), TranslationRule>,
144    /// Decomposition cache
145    decomposition_cache: HashMap<String, Vec<DecomposedGate>>,
146}
147
148/// Translation rule for a specific gate
149#[derive(Debug, Clone)]
150pub struct TranslationRule {
151    /// Gate name to translate
152    pub gate_name: String,
153    /// Translation method
154    pub method: TranslationMethod,
155    /// Expected fidelity after translation
156    pub fidelity: f64,
157    /// Number of native gates after translation
158    pub gate_count: usize,
159}
160
161/// Methods for translating gates
162pub enum TranslationMethod {
163    /// Direct mapping to native gate
164    Direct(String),
165    /// Fixed decomposition
166    FixedDecomposition(Vec<DecomposedGate>),
167    /// Parameterized decomposition
168    ParameterizedDecomposition(Box<dyn Fn(Vec<f64>) -> Vec<DecomposedGate> + Send + Sync>),
169    /// Use synthesis algorithm
170    Synthesis(SynthesisMethod),
171    /// Custom translation function
172    Custom(Box<dyn Fn(&dyn GateOp) -> QuantRS2Result<Vec<DecomposedGate>> + Send + Sync>),
173}
174
175impl std::fmt::Debug for TranslationMethod {
176    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
177        match self {
178            Self::Direct(s) => write!(f, "Direct({})", s),
179            Self::FixedDecomposition(gates) => write!(f, "FixedDecomposition({:?})", gates),
180            Self::ParameterizedDecomposition(_) => {
181                write!(f, "ParameterizedDecomposition(<function>)")
182            }
183            Self::Synthesis(method) => write!(f, "Synthesis({:?})", method),
184            Self::Custom(_) => write!(f, "Custom(<function>)"),
185        }
186    }
187}
188
189impl Clone for TranslationMethod {
190    fn clone(&self) -> Self {
191        match self {
192            Self::Direct(s) => Self::Direct(s.clone()),
193            Self::FixedDecomposition(gates) => Self::FixedDecomposition(gates.clone()),
194            Self::ParameterizedDecomposition(_) => {
195                panic!(
196                    "Cannot clone ParameterizedDecomposition - use Arc<TranslationMethod> instead"
197                )
198            }
199            Self::Synthesis(method) => Self::Synthesis(method.clone()),
200            Self::Custom(_) => {
201                panic!("Cannot clone Custom - use Arc<TranslationMethod> instead")
202            }
203        }
204    }
205}
206
207/// Decomposed gate representation
208#[derive(Debug, Clone)]
209pub struct DecomposedGate {
210    /// Gate name in native set
211    pub native_gate: String,
212    /// Target qubits
213    pub qubits: Vec<QubitId>,
214    /// Parameters (if any)
215    pub parameters: Vec<f64>,
216    /// Optional global phase
217    pub global_phase: Option<f64>,
218}
219
220/// Synthesis methods for gate decomposition
221#[derive(Debug, Clone, Copy)]
222pub enum SynthesisMethod {
223    /// Single-qubit synthesis (ZYZ, XYX, etc.)
224    SingleQubitZYZ,
225    SingleQubitXYX,
226    SingleQubitU3,
227    /// Two-qubit synthesis
228    KAKDecomposition,
229    /// Clifford+T synthesis
230    CliffordT,
231    /// Solovay-Kitaev
232    SolovayKitaev,
233}
234
235impl GateTranslator {
236    /// Create a new gate translator
237    pub fn new() -> Self {
238        let mut translator = Self {
239            native_gates: HashMap::new(),
240            translation_rules: HashMap::new(),
241            decomposition_cache: HashMap::new(),
242        };
243
244        // Initialize standard backend gate sets
245        translator.init_ibm_gates();
246        translator.init_google_gates();
247        translator.init_ionq_gates();
248        translator.init_rigetti_gates();
249        translator.init_amazon_gates();
250        translator.init_azure_gates();
251        translator.init_honeywell_gates();
252
253        translator
254    }
255
256    /// Initialize IBM Quantum native gates
257    fn init_ibm_gates(&mut self) {
258        let gate_set = NativeGateSet {
259            backend: HardwareBackend::IBMQuantum,
260            single_qubit_gates: vec![
261                "id".to_string(),
262                "rz".to_string(),
263                "sx".to_string(),
264                "x".to_string(),
265            ],
266            two_qubit_gates: vec!["cx".to_string()],
267            multi_qubit_gates: vec![],
268            arbitrary_single_qubit: false,
269            rotation_axes: vec![RotationAxis::Z],
270            constraints: BackendConstraints {
271                max_depth: None,
272                discrete_angles: None,
273                virtual_z: true,
274                coupling_map: None,
275                timing_constraints: None,
276            },
277        };
278
279        self.native_gates
280            .insert(HardwareBackend::IBMQuantum, gate_set);
281
282        // Add translation rules
283        self.add_ibm_translation_rules();
284    }
285
286    /// Add IBM-specific translation rules
287    fn add_ibm_translation_rules(&mut self) {
288        let backend = HardwareBackend::IBMQuantum;
289
290        // H = RZ(π/2) SX RZ(π/2)
291        self.translation_rules.insert(
292            (backend, "H".to_string()),
293            TranslationRule {
294                gate_name: "H".to_string(),
295                method: TranslationMethod::FixedDecomposition(vec![
296                    DecomposedGate {
297                        native_gate: "rz".to_string(),
298                        qubits: vec![QubitId(0)],
299                        parameters: vec![PI / 2.0],
300                        global_phase: None,
301                    },
302                    DecomposedGate {
303                        native_gate: "sx".to_string(),
304                        qubits: vec![QubitId(0)],
305                        parameters: vec![],
306                        global_phase: None,
307                    },
308                    DecomposedGate {
309                        native_gate: "rz".to_string(),
310                        qubits: vec![QubitId(0)],
311                        parameters: vec![PI / 2.0],
312                        global_phase: None,
313                    },
314                ]),
315                fidelity: 0.9999,
316                gate_count: 3,
317            },
318        );
319
320        // Y = RZ(π) X
321        self.translation_rules.insert(
322            (backend, "Y".to_string()),
323            TranslationRule {
324                gate_name: "Y".to_string(),
325                method: TranslationMethod::FixedDecomposition(vec![
326                    DecomposedGate {
327                        native_gate: "rz".to_string(),
328                        qubits: vec![QubitId(0)],
329                        parameters: vec![PI],
330                        global_phase: None,
331                    },
332                    DecomposedGate {
333                        native_gate: "x".to_string(),
334                        qubits: vec![QubitId(0)],
335                        parameters: vec![],
336                        global_phase: None,
337                    },
338                ]),
339                fidelity: 0.9999,
340                gate_count: 2,
341            },
342        );
343
344        // S = RZ(π/2)
345        self.translation_rules.insert(
346            (backend, "S".to_string()),
347            TranslationRule {
348                gate_name: "S".to_string(),
349                method: TranslationMethod::Direct("rz".to_string()),
350                fidelity: 1.0,
351                gate_count: 1,
352            },
353        );
354
355        // T = RZ(π/4)
356        self.translation_rules.insert(
357            (backend, "T".to_string()),
358            TranslationRule {
359                gate_name: "T".to_string(),
360                method: TranslationMethod::Direct("rz".to_string()),
361                fidelity: 1.0,
362                gate_count: 1,
363            },
364        );
365
366        // RX using RZ and X gates
367        self.translation_rules.insert(
368            (backend, "RX".to_string()),
369            TranslationRule {
370                gate_name: "RX".to_string(),
371                method: TranslationMethod::ParameterizedDecomposition(Box::new(|params| {
372                    let theta = params[0];
373                    vec![
374                        DecomposedGate {
375                            native_gate: "rz".to_string(),
376                            qubits: vec![QubitId(0)],
377                            parameters: vec![PI / 2.0],
378                            global_phase: None,
379                        },
380                        DecomposedGate {
381                            native_gate: "sx".to_string(),
382                            qubits: vec![QubitId(0)],
383                            parameters: vec![],
384                            global_phase: None,
385                        },
386                        DecomposedGate {
387                            native_gate: "rz".to_string(),
388                            qubits: vec![QubitId(0)],
389                            parameters: vec![theta - PI / 2.0],
390                            global_phase: None,
391                        },
392                        DecomposedGate {
393                            native_gate: "sx".to_string(),
394                            qubits: vec![QubitId(0)],
395                            parameters: vec![],
396                            global_phase: None,
397                        },
398                        DecomposedGate {
399                            native_gate: "rz".to_string(),
400                            qubits: vec![QubitId(0)],
401                            parameters: vec![-PI / 2.0],
402                            global_phase: None,
403                        },
404                    ]
405                })),
406                fidelity: 0.9998,
407                gate_count: 5,
408            },
409        );
410
411        // CNOT is called CX in IBM
412        self.translation_rules.insert(
413            (backend, "CNOT".to_string()),
414            TranslationRule {
415                gate_name: "CNOT".to_string(),
416                method: TranslationMethod::Direct("cx".to_string()),
417                fidelity: 1.0,
418                gate_count: 1,
419            },
420        );
421    }
422
423    /// Initialize Google Sycamore native gates
424    fn init_google_gates(&mut self) {
425        let gate_set = NativeGateSet {
426            backend: HardwareBackend::GoogleSycamore,
427            single_qubit_gates: vec![
428                "ph".to_string(),    // Phase gate
429                "x_pow".to_string(), // X^t gate
430                "y_pow".to_string(), // Y^t gate
431                "z_pow".to_string(), // Z^t gate
432            ],
433            two_qubit_gates: vec![
434                "syc".to_string(), // Sycamore gate
435                "sqrt_iswap".to_string(),
436            ],
437            multi_qubit_gates: vec![],
438            arbitrary_single_qubit: true,
439            rotation_axes: vec![RotationAxis::X, RotationAxis::Y, RotationAxis::Z],
440            constraints: BackendConstraints {
441                max_depth: None,
442                discrete_angles: None,
443                virtual_z: false,
444                coupling_map: None,
445                timing_constraints: None,
446            },
447        };
448
449        self.native_gates
450            .insert(HardwareBackend::GoogleSycamore, gate_set);
451        self.add_google_translation_rules();
452    }
453
454    /// Add Google-specific translation rules
455    fn add_google_translation_rules(&mut self) {
456        let backend = HardwareBackend::GoogleSycamore;
457
458        // Direct mappings for powered gates
459        self.translation_rules.insert(
460            (backend, "X".to_string()),
461            TranslationRule {
462                gate_name: "X".to_string(),
463                method: TranslationMethod::FixedDecomposition(vec![DecomposedGate {
464                    native_gate: "x_pow".to_string(),
465                    qubits: vec![QubitId(0)],
466                    parameters: vec![1.0],
467                    global_phase: None,
468                }]),
469                fidelity: 1.0,
470                gate_count: 1,
471            },
472        );
473
474        // CNOT using Sycamore gates
475        self.translation_rules.insert(
476            (backend, "CNOT".to_string()),
477            TranslationRule {
478                gate_name: "CNOT".to_string(),
479                method: TranslationMethod::FixedDecomposition(vec![
480                    // This is a simplified version - actual decomposition is more complex
481                    DecomposedGate {
482                        native_gate: "syc".to_string(),
483                        qubits: vec![QubitId(0), QubitId(1)],
484                        parameters: vec![],
485                        global_phase: None,
486                    },
487                    // Additional single-qubit corrections would go here
488                ]),
489                fidelity: 0.998,
490                gate_count: 3,
491            },
492        );
493    }
494
495    /// Initialize IonQ native gates
496    fn init_ionq_gates(&mut self) {
497        let gate_set = NativeGateSet {
498            backend: HardwareBackend::IonQ,
499            single_qubit_gates: vec!["rx".to_string(), "ry".to_string(), "rz".to_string()],
500            two_qubit_gates: vec![
501                "xx".to_string(), // Mølmer-Sørensen gate
502            ],
503            multi_qubit_gates: vec![],
504            arbitrary_single_qubit: true,
505            rotation_axes: vec![RotationAxis::X, RotationAxis::Y, RotationAxis::Z],
506            constraints: BackendConstraints {
507                max_depth: None,
508                discrete_angles: None,
509                virtual_z: false,
510                coupling_map: None, // All-to-all connectivity
511                timing_constraints: None,
512            },
513        };
514
515        self.native_gates.insert(HardwareBackend::IonQ, gate_set);
516        self.add_ionq_translation_rules();
517    }
518
519    /// Add IonQ-specific translation rules
520    fn add_ionq_translation_rules(&mut self) {
521        let backend = HardwareBackend::IonQ;
522
523        // CNOT using XX gate
524        self.translation_rules.insert(
525            (backend, "CNOT".to_string()),
526            TranslationRule {
527                gate_name: "CNOT".to_string(),
528                method: TranslationMethod::FixedDecomposition(vec![
529                    DecomposedGate {
530                        native_gate: "ry".to_string(),
531                        qubits: vec![QubitId(0)],
532                        parameters: vec![PI / 2.0],
533                        global_phase: None,
534                    },
535                    DecomposedGate {
536                        native_gate: "xx".to_string(),
537                        qubits: vec![QubitId(0), QubitId(1)],
538                        parameters: vec![PI / 2.0],
539                        global_phase: None,
540                    },
541                    DecomposedGate {
542                        native_gate: "rx".to_string(),
543                        qubits: vec![QubitId(0)],
544                        parameters: vec![-PI / 2.0],
545                        global_phase: None,
546                    },
547                    DecomposedGate {
548                        native_gate: "rx".to_string(),
549                        qubits: vec![QubitId(1)],
550                        parameters: vec![-PI / 2.0],
551                        global_phase: None,
552                    },
553                    DecomposedGate {
554                        native_gate: "ry".to_string(),
555                        qubits: vec![QubitId(0)],
556                        parameters: vec![-PI / 2.0],
557                        global_phase: None,
558                    },
559                ]),
560                fidelity: 0.999,
561                gate_count: 5,
562            },
563        );
564    }
565
566    /// Initialize Rigetti native gates
567    fn init_rigetti_gates(&mut self) {
568        let gate_set = NativeGateSet {
569            backend: HardwareBackend::Rigetti,
570            single_qubit_gates: vec!["rx".to_string(), "rz".to_string()],
571            two_qubit_gates: vec![
572                "cz".to_string(),
573                "xy".to_string(), // Parametrized XY gate
574            ],
575            multi_qubit_gates: vec![],
576            arbitrary_single_qubit: true,
577            rotation_axes: vec![RotationAxis::X, RotationAxis::Z],
578            constraints: BackendConstraints {
579                max_depth: None,
580                discrete_angles: None,
581                virtual_z: false,
582                coupling_map: None,
583                timing_constraints: None,
584            },
585        };
586
587        self.native_gates.insert(HardwareBackend::Rigetti, gate_set);
588    }
589
590    /// Initialize Amazon Braket native gates
591    fn init_amazon_gates(&mut self) {
592        // Amazon supports multiple backends, this is a generic set
593        let gate_set = NativeGateSet {
594            backend: HardwareBackend::AmazonBraket,
595            single_qubit_gates: vec![
596                "h".to_string(),
597                "x".to_string(),
598                "y".to_string(),
599                "z".to_string(),
600                "rx".to_string(),
601                "ry".to_string(),
602                "rz".to_string(),
603            ],
604            two_qubit_gates: vec!["cnot".to_string(), "cz".to_string(), "swap".to_string()],
605            multi_qubit_gates: vec!["ccnot".to_string()],
606            arbitrary_single_qubit: true,
607            rotation_axes: vec![RotationAxis::X, RotationAxis::Y, RotationAxis::Z],
608            constraints: BackendConstraints {
609                max_depth: None,
610                discrete_angles: None,
611                virtual_z: false,
612                coupling_map: None,
613                timing_constraints: None,
614            },
615        };
616
617        self.native_gates
618            .insert(HardwareBackend::AmazonBraket, gate_set);
619    }
620
621    /// Initialize Azure Quantum native gates
622    fn init_azure_gates(&mut self) {
623        // Azure supports multiple backends, this is a generic set
624        let gate_set = NativeGateSet {
625            backend: HardwareBackend::AzureQuantum,
626            single_qubit_gates: vec![
627                "h".to_string(),
628                "x".to_string(),
629                "y".to_string(),
630                "z".to_string(),
631                "s".to_string(),
632                "t".to_string(),
633                "rx".to_string(),
634                "ry".to_string(),
635                "rz".to_string(),
636            ],
637            two_qubit_gates: vec!["cnot".to_string(), "cz".to_string()],
638            multi_qubit_gates: vec![],
639            arbitrary_single_qubit: true,
640            rotation_axes: vec![RotationAxis::X, RotationAxis::Y, RotationAxis::Z],
641            constraints: BackendConstraints {
642                max_depth: None,
643                discrete_angles: None,
644                virtual_z: false,
645                coupling_map: None,
646                timing_constraints: None,
647            },
648        };
649
650        self.native_gates
651            .insert(HardwareBackend::AzureQuantum, gate_set);
652    }
653
654    /// Initialize Honeywell/Quantinuum native gates
655    fn init_honeywell_gates(&mut self) {
656        let gate_set = NativeGateSet {
657            backend: HardwareBackend::Honeywell,
658            single_qubit_gates: vec![
659                "u1".to_string(), // Phase gate
660                "u2".to_string(), // Single-qubit gate
661                "u3".to_string(), // General single-qubit gate
662            ],
663            two_qubit_gates: vec![
664                "zz".to_string(), // Native ZZ interaction
665            ],
666            multi_qubit_gates: vec![],
667            arbitrary_single_qubit: true,
668            rotation_axes: vec![RotationAxis::Custom(1.0, 0.0, 0.0)],
669            constraints: BackendConstraints {
670                max_depth: None,
671                discrete_angles: None,
672                virtual_z: false,
673                coupling_map: None, // All-to-all connectivity
674                timing_constraints: None,
675            },
676        };
677
678        self.native_gates
679            .insert(HardwareBackend::Honeywell, gate_set);
680    }
681
682    /// Get native gate set for a backend
683    pub fn get_native_gates(&self, backend: HardwareBackend) -> Option<&NativeGateSet> {
684        self.native_gates.get(&backend)
685    }
686
687    /// Check if a gate is native to a backend
688    pub fn is_native_gate(&self, backend: HardwareBackend, gate_name: &str) -> bool {
689        if let Some(gate_set) = self.native_gates.get(&backend) {
690            gate_set.single_qubit_gates.contains(&gate_name.to_string())
691                || gate_set.two_qubit_gates.contains(&gate_name.to_string())
692                || gate_set.multi_qubit_gates.contains(&gate_name.to_string())
693        } else {
694            false
695        }
696    }
697
698    /// Translate a gate to native gate set
699    pub fn translate_gate(
700        &mut self,
701        gate: &dyn GateOp,
702        backend: HardwareBackend,
703    ) -> QuantRS2Result<Vec<DecomposedGate>> {
704        let gate_name = gate.name();
705
706        // Check if already native
707        if self.is_native_gate(backend, gate_name) {
708            return Ok(vec![DecomposedGate {
709                native_gate: gate_name.to_string(),
710                qubits: gate.qubits(),
711                parameters: self.extract_parameters(gate)?,
712                global_phase: None,
713            }]);
714        }
715
716        // Check cache
717        let cache_key = format!("{}_{:?}", gate_name, backend);
718        if let Some(cached) = self.decomposition_cache.get(&cache_key) {
719            return Ok(self.remap_qubits(cached.clone(), &gate.qubits()));
720        }
721
722        // Look for translation rule
723        if let Some(rule) = self
724            .translation_rules
725            .get(&(backend, gate_name.to_string()))
726        {
727            let decomposition = match &rule.method {
728                TranslationMethod::Direct(native_name) => {
729                    vec![DecomposedGate {
730                        native_gate: native_name.clone(),
731                        qubits: gate.qubits(),
732                        parameters: self.extract_parameters(gate)?,
733                        global_phase: None,
734                    }]
735                }
736                TranslationMethod::FixedDecomposition(gates) => {
737                    self.remap_qubits(gates.clone(), &gate.qubits())
738                }
739                TranslationMethod::ParameterizedDecomposition(func) => {
740                    let params = self.extract_parameters(gate)?;
741                    let gates = func(params);
742                    self.remap_qubits(gates, &gate.qubits())
743                }
744                TranslationMethod::Synthesis(method) => {
745                    self.synthesize_gate(gate, *method, backend)?
746                }
747                TranslationMethod::Custom(func) => func(gate)?,
748            };
749
750            // Cache the result
751            self.decomposition_cache
752                .insert(cache_key, decomposition.clone());
753            return Ok(decomposition);
754        }
755
756        // Fall back to synthesis based on gate type
757        match gate.num_qubits() {
758            1 => self.synthesize_gate(gate, SynthesisMethod::SingleQubitZYZ, backend),
759            2 => self.synthesize_gate(gate, SynthesisMethod::KAKDecomposition, backend),
760            _ => Err(QuantRS2Error::InvalidInput(format!(
761                "No translation available for {}-qubit gate {}",
762                gate.num_qubits(),
763                gate_name
764            ))),
765        }
766    }
767
768    /// Translate an entire circuit
769    pub fn translate_circuit<const N: usize>(
770        &mut self,
771        circuit: &Circuit<N>,
772        backend: HardwareBackend,
773    ) -> QuantRS2Result<Circuit<N>> {
774        let mut translated = Circuit::<N>::new();
775
776        for gate in circuit.gates() {
777            let decomposed = self.translate_gate(gate.as_ref(), backend)?;
778
779            for dec_gate in decomposed {
780                self.add_decomposed_gate(&mut translated, &dec_gate)?;
781            }
782        }
783
784        Ok(translated)
785    }
786
787    /// Extract parameters from a gate
788    fn extract_parameters(&self, gate: &dyn GateOp) -> QuantRS2Result<Vec<f64>> {
789        // This would need to be implemented based on gate type
790        // For now, return empty vector
791        Ok(vec![])
792    }
793
794    /// Remap qubits in decomposition
795    fn remap_qubits(
796        &self,
797        mut gates: Vec<DecomposedGate>,
798        actual_qubits: &[QubitId],
799    ) -> Vec<DecomposedGate> {
800        for gate in &mut gates {
801            for qubit in &mut gate.qubits {
802                if qubit.id() < actual_qubits.len() as u32 {
803                    *qubit = actual_qubits[qubit.id() as usize];
804                }
805            }
806        }
807        gates
808    }
809
810    /// Synthesize a gate using specified method
811    fn synthesize_gate(
812        &self,
813        gate: &dyn GateOp,
814        method: SynthesisMethod,
815        backend: HardwareBackend,
816    ) -> QuantRS2Result<Vec<DecomposedGate>> {
817        match method {
818            SynthesisMethod::SingleQubitZYZ => {
819                // Use ZYZ decomposition for single-qubit gates
820                if gate.num_qubits() != 1 {
821                    return Err(QuantRS2Error::InvalidInput(
822                        "ZYZ synthesis only works for single-qubit gates".into(),
823                    ));
824                }
825
826                let matrix_vec = gate.matrix()?;
827                let matrix = Array2::from_shape_vec((2, 2), matrix_vec)
828                    .map_err(|_| QuantRS2Error::InvalidInput("Invalid matrix shape".into()))?;
829                let decomp = decompose_single_qubit_zyz(&matrix.view())?;
830
831                Ok(vec![
832                    DecomposedGate {
833                        native_gate: "rz".to_string(),
834                        qubits: gate.qubits(),
835                        parameters: vec![decomp.theta1],
836                        global_phase: None,
837                    },
838                    DecomposedGate {
839                        native_gate: "ry".to_string(),
840                        qubits: gate.qubits(),
841                        parameters: vec![decomp.phi],
842                        global_phase: None,
843                    },
844                    DecomposedGate {
845                        native_gate: "rz".to_string(),
846                        qubits: gate.qubits(),
847                        parameters: vec![decomp.theta2],
848                        global_phase: Some(decomp.global_phase),
849                    },
850                ])
851            }
852            SynthesisMethod::KAKDecomposition => {
853                // Use KAK decomposition for two-qubit gates
854                if gate.num_qubits() != 2 {
855                    return Err(QuantRS2Error::InvalidInput(
856                        "KAK decomposition only works for two-qubit gates".into(),
857                    ));
858                }
859
860                // This would use the KAK decomposition from core
861                // For now, return a placeholder
862                Ok(vec![])
863            }
864            _ => Err(QuantRS2Error::InvalidInput(format!(
865                "Synthesis method {:?} not yet implemented",
866                method
867            ))),
868        }
869    }
870
871    /// Add a decomposed gate to circuit
872    fn add_decomposed_gate<const N: usize>(
873        &self,
874        circuit: &mut Circuit<N>,
875        gate: &DecomposedGate,
876    ) -> QuantRS2Result<()> {
877        match gate.native_gate.as_str() {
878            // IBM gates
879            "id" => {} // Identity, do nothing
880            "x" => {
881                let _ = circuit.x(gate.qubits[0]);
882            }
883            "sx" => {
884                let _ = circuit.sx(gate.qubits[0]);
885            }
886            "rz" => {
887                let _ = circuit.rz(gate.qubits[0], gate.parameters[0]);
888            }
889            "cx" => {
890                let _ = circuit.cnot(gate.qubits[0], gate.qubits[1]);
891            }
892
893            // IonQ gates
894            "rx" => {
895                let _ = circuit.rx(gate.qubits[0], gate.parameters[0]);
896            }
897            "ry" => {
898                let _ = circuit.ry(gate.qubits[0], gate.parameters[0]);
899            }
900            "xx" => {
901                // XX gate would need to be added to circuit builder
902                // For now, decompose to CNOT
903                let _ = circuit.cnot(gate.qubits[0], gate.qubits[1]);
904            }
905
906            // Common gates
907            "h" => {
908                let _ = circuit.h(gate.qubits[0]);
909            }
910            "y" => {
911                let _ = circuit.y(gate.qubits[0]);
912            }
913            "z" => {
914                let _ = circuit.z(gate.qubits[0]);
915            }
916            "s" => {
917                let _ = circuit.s(gate.qubits[0]);
918            }
919            "t" => {
920                let _ = circuit.t(gate.qubits[0]);
921            }
922            "cnot" => {
923                let _ = circuit.cnot(gate.qubits[0], gate.qubits[1]);
924            }
925            "cz" => {
926                let _ = circuit.cz(gate.qubits[0], gate.qubits[1]);
927            }
928            "swap" => {
929                let _ = circuit.swap(gate.qubits[0], gate.qubits[1]);
930            }
931            "ccnot" => {
932                let _ = circuit.toffoli(gate.qubits[0], gate.qubits[1], gate.qubits[2]);
933            }
934
935            _ => {
936                return Err(QuantRS2Error::InvalidInput(format!(
937                    "Unknown native gate: {}",
938                    gate.native_gate
939                )));
940            }
941        }
942
943        Ok(())
944    }
945}
946
947/// Translation optimizer that minimizes gate count or error
948pub struct TranslationOptimizer {
949    /// Gate translator
950    translator: GateTranslator,
951    /// Optimization strategy
952    strategy: OptimizationStrategy,
953}
954
955/// Optimization strategies for translation
956#[derive(Debug, Clone, Copy)]
957pub enum OptimizationStrategy {
958    /// Minimize gate count
959    MinimizeGateCount,
960    /// Minimize error (maximize fidelity)
961    MinimizeError,
962    /// Minimize circuit depth
963    MinimizeDepth,
964    /// Balance between gate count and error
965    Balanced { weight: f64 },
966}
967
968impl TranslationOptimizer {
969    /// Create a new translation optimizer
970    pub fn new(strategy: OptimizationStrategy) -> Self {
971        Self {
972            translator: GateTranslator::new(),
973            strategy,
974        }
975    }
976
977    /// Find optimal translation for a gate
978    pub fn optimize_translation(
979        &mut self,
980        gate: &dyn GateOp,
981        backend: HardwareBackend,
982    ) -> QuantRS2Result<Vec<DecomposedGate>> {
983        // Try multiple translation methods and pick the best
984        let candidates = vec![
985            self.translator.translate_gate(gate, backend)?,
986            // Could try alternative decompositions here
987        ];
988
989        // Select best based on strategy
990        let best = match self.strategy {
991            OptimizationStrategy::MinimizeGateCount => candidates
992                .into_iter()
993                .min_by_key(|c| c.len())
994                .unwrap_or_default(),
995            OptimizationStrategy::MinimizeError => {
996                // Would need fidelity information
997                candidates.into_iter().next().unwrap_or_default()
998            }
999            OptimizationStrategy::MinimizeDepth => {
1000                // Would need to calculate depth
1001                candidates.into_iter().next().unwrap_or_default()
1002            }
1003            OptimizationStrategy::Balanced { weight } => {
1004                // Weighted optimization
1005                candidates.into_iter().next().unwrap_or_default()
1006            }
1007        };
1008
1009        Ok(best)
1010    }
1011}
1012
1013/// Validate that a circuit uses only native gates
1014pub fn validate_native_circuit<const N: usize>(
1015    circuit: &Circuit<N>,
1016    backend: HardwareBackend,
1017) -> QuantRS2Result<bool> {
1018    let translator = GateTranslator::new();
1019
1020    for gate in circuit.gates() {
1021        if !translator.is_native_gate(backend, gate.name()) {
1022            return Ok(false);
1023        }
1024    }
1025
1026    Ok(true)
1027}
1028
1029/// Get translation statistics for a circuit
1030pub struct TranslationStats {
1031    /// Original gate count
1032    pub original_gates: usize,
1033    /// Native gate count after translation
1034    pub native_gates: usize,
1035    /// Gate count by type
1036    pub gate_counts: HashMap<String, usize>,
1037    /// Estimated fidelity loss
1038    pub fidelity_loss: f64,
1039    /// Circuit depth change
1040    pub depth_ratio: f64,
1041}
1042
1043impl TranslationStats {
1044    /// Calculate statistics for a translation
1045    pub fn calculate<const N: usize>(
1046        original: &Circuit<N>,
1047        translated: &Circuit<N>,
1048        backend: HardwareBackend,
1049    ) -> Self {
1050        let mut gate_counts = HashMap::new();
1051
1052        for gate in translated.gates() {
1053            *gate_counts.entry(gate.name().to_string()).or_insert(0) += 1;
1054        }
1055
1056        Self {
1057            original_gates: original.gates().len(),
1058            native_gates: translated.gates().len(),
1059            gate_counts,
1060            fidelity_loss: 0.0, // Would need to calculate
1061            depth_ratio: 1.0,   // Would need to calculate
1062        }
1063    }
1064}
1065
1066#[cfg(test)]
1067mod tests {
1068    use super::*;
1069
1070    #[test]
1071    fn test_gate_translator_creation() {
1072        let translator = GateTranslator::new();
1073
1074        // Check that standard backends are initialized
1075        assert!(translator
1076            .get_native_gates(HardwareBackend::IBMQuantum)
1077            .is_some());
1078        assert!(translator
1079            .get_native_gates(HardwareBackend::GoogleSycamore)
1080            .is_some());
1081        assert!(translator.get_native_gates(HardwareBackend::IonQ).is_some());
1082    }
1083
1084    #[test]
1085    fn test_native_gate_check() {
1086        let translator = GateTranslator::new();
1087
1088        // IBM native gates
1089        assert!(translator.is_native_gate(HardwareBackend::IBMQuantum, "rz"));
1090        assert!(translator.is_native_gate(HardwareBackend::IBMQuantum, "sx"));
1091        assert!(translator.is_native_gate(HardwareBackend::IBMQuantum, "cx"));
1092        assert!(!translator.is_native_gate(HardwareBackend::IBMQuantum, "h"));
1093
1094        // IonQ native gates
1095        assert!(translator.is_native_gate(HardwareBackend::IonQ, "rx"));
1096        assert!(translator.is_native_gate(HardwareBackend::IonQ, "xx"));
1097        assert!(!translator.is_native_gate(HardwareBackend::IonQ, "cnot"));
1098    }
1099
1100    #[test]
1101    fn test_hadamard_translation_ibm() {
1102        let mut translator = GateTranslator::new();
1103        let h_gate = Hadamard { target: QubitId(0) };
1104
1105        let decomposed = translator
1106            .translate_gate(&h_gate, HardwareBackend::IBMQuantum)
1107            .unwrap();
1108
1109        // H = RZ(π/2) SX RZ(π/2)
1110        assert_eq!(decomposed.len(), 3);
1111        assert_eq!(decomposed[0].native_gate, "rz");
1112        assert_eq!(decomposed[1].native_gate, "sx");
1113        assert_eq!(decomposed[2].native_gate, "rz");
1114    }
1115
1116    #[test]
1117    fn test_circuit_translation() {
1118        let mut translator = GateTranslator::new();
1119
1120        let mut circuit = Circuit::<2>::new();
1121        let _ = circuit.h(QubitId(0));
1122        let _ = circuit.cnot(QubitId(0), QubitId(1));
1123
1124        let translated = translator
1125            .translate_circuit(&circuit, HardwareBackend::IBMQuantum)
1126            .unwrap();
1127
1128        // Original: H, CNOT
1129        // Translated: RZ, SX, RZ, CX
1130        assert!(translated.gates().len() >= 4);
1131    }
1132}
quantrs2_device/translation.rs

quantrs2_device/
translation.rs
