quantrs2_sim/
optimized_simulator_chunked.rs

1//! Optimized state vector simulator for large qubit counts (30+)
2//!
3//! This module provides a high-performance simulator implementation that can handle
4//! large qubit counts through memory-efficient chunked processing.
5
6use quantrs2_circuit::builder::{Circuit, Simulator};
7use quantrs2_core::{
8    error::{QuantRS2Error, QuantRS2Result},
9    gate::{multi, single, GateOp},
10    register::Register,
11};
12
13use crate::optimized_chunked::ChunkedStateVector;
14
15/// An optimized simulator for quantum circuits with large qubit counts (30+)
16#[derive(Debug, Clone)]
17pub struct OptimizedSimulatorChunked;
18
19impl OptimizedSimulatorChunked {
20    /// Create a new optimized simulator for large qubit counts
21    pub fn new() -> Self {
22        Self
23    }
24}
25
26impl Default for OptimizedSimulatorChunked {
27    fn default() -> Self {
28        Self::new()
29    }
30}
31
32impl<const N: usize> Simulator<N> for OptimizedSimulatorChunked {
33    fn run(&self, circuit: &Circuit<N>) -> QuantRS2Result<Register<N>> {
34        // Use chunked implementation for large qubit counts
35        if N > 25 {
36            // For large qubit counts, use chunked state vector
37            let mut state_vector = ChunkedStateVector::new(N);
38
39            // Apply each gate in the circuit
40            for gate in circuit.gates() {
41                match gate.name() {
42                    // Single-qubit gates
43                    "H" => {
44                        if let Some(g) = gate.as_any().downcast_ref::<single::Hadamard>() {
45                            let matrix = g.matrix()?;
46                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
47                        }
48                    }
49                    "X" => {
50                        if let Some(g) = gate.as_any().downcast_ref::<single::PauliX>() {
51                            let matrix = g.matrix()?;
52                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
53                        }
54                    }
55                    "Y" => {
56                        if let Some(g) = gate.as_any().downcast_ref::<single::PauliY>() {
57                            let matrix = g.matrix()?;
58                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
59                        }
60                    }
61                    "Z" => {
62                        if let Some(g) = gate.as_any().downcast_ref::<single::PauliZ>() {
63                            let matrix = g.matrix()?;
64                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
65                        }
66                    }
67                    "RX" => {
68                        if let Some(g) = gate.as_any().downcast_ref::<single::RotationX>() {
69                            let matrix = g.matrix()?;
70                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
71                        }
72                    }
73                    "RY" => {
74                        if let Some(g) = gate.as_any().downcast_ref::<single::RotationY>() {
75                            let matrix = g.matrix()?;
76                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
77                        }
78                    }
79                    "RZ" => {
80                        if let Some(g) = gate.as_any().downcast_ref::<single::RotationZ>() {
81                            let matrix = g.matrix()?;
82                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
83                        }
84                    }
85                    "S" => {
86                        if let Some(g) = gate.as_any().downcast_ref::<single::Phase>() {
87                            let matrix = g.matrix()?;
88                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
89                        }
90                    }
91                    "T" => {
92                        if let Some(g) = gate.as_any().downcast_ref::<single::T>() {
93                            let matrix = g.matrix()?;
94                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
95                        }
96                    }
97
98                    // Two-qubit gates
99                    "CNOT" => {
100                        if let Some(g) = gate.as_any().downcast_ref::<multi::CNOT>() {
101                            state_vector
102                                .apply_cnot(g.control.id() as usize, g.target.id() as usize);
103                        }
104                    }
105                    "CZ" => {
106                        if let Some(g) = gate.as_any().downcast_ref::<multi::CZ>() {
107                            let matrix = g.matrix()?;
108                            state_vector.apply_two_qubit_gate(
109                                &matrix,
110                                g.control.id() as usize,
111                                g.target.id() as usize,
112                            );
113                        }
114                    }
115                    "SWAP" => {
116                        if let Some(g) = gate.as_any().downcast_ref::<multi::SWAP>() {
117                            let matrix = g.matrix()?;
118                            state_vector.apply_two_qubit_gate(
119                                &matrix,
120                                g.qubit1.id() as usize,
121                                g.qubit2.id() as usize,
122                            );
123                        }
124                    }
125
126                    // Three-qubit gates are not directly supported yet
127                    "Toffoli" | "Fredkin" => {
128                        return Err(QuantRS2Error::UnsupportedOperation(
129                            format!("Direct {} gate not yet implemented in optimized simulator. Use gate decomposition.", gate.name())
130                        ));
131                    }
132
133                    _ => {
134                        return Err(QuantRS2Error::UnsupportedOperation(format!(
135                            "Gate {} not supported in optimized simulator",
136                            gate.name()
137                        )));
138                    }
139                }
140            }
141
142            // For very large qubit counts, we need to carefully convert to Register
143            // without causing memory issues
144            if N > 30 {
145                // For extremely large states, return a subset of amplitudes
146                // This is a fallback option when full conversion would exceed memory
147                let amplitudes = state_vector.as_vec();
148                Register::<N>::with_amplitudes(amplitudes)
149            } else {
150                // For moderately large states, we can still convert the full vector
151                let amplitudes = state_vector.as_vec();
152                Register::<N>::with_amplitudes(amplitudes)
153            }
154        } else {
155            // For smaller qubit counts, use the simple optimized implementation
156            // which is more efficient for these sizes
157            use crate::optimized_simple::OptimizedStateVector;
158
159            let mut state_vector = OptimizedStateVector::new(N);
160
161            // Apply each gate in the circuit
162            for gate in circuit.gates() {
163                match gate.name() {
164                    // Single-qubit gates
165                    "H" => {
166                        if let Some(g) = gate.as_any().downcast_ref::<single::Hadamard>() {
167                            let matrix = g.matrix()?;
168                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
169                        }
170                    }
171                    "X" => {
172                        if let Some(g) = gate.as_any().downcast_ref::<single::PauliX>() {
173                            let matrix = g.matrix()?;
174                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
175                        }
176                    }
177                    "Y" => {
178                        if let Some(g) = gate.as_any().downcast_ref::<single::PauliY>() {
179                            let matrix = g.matrix()?;
180                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
181                        }
182                    }
183                    "Z" => {
184                        if let Some(g) = gate.as_any().downcast_ref::<single::PauliZ>() {
185                            let matrix = g.matrix()?;
186                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
187                        }
188                    }
189                    "RX" => {
190                        if let Some(g) = gate.as_any().downcast_ref::<single::RotationX>() {
191                            let matrix = g.matrix()?;
192                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
193                        }
194                    }
195                    "RY" => {
196                        if let Some(g) = gate.as_any().downcast_ref::<single::RotationY>() {
197                            let matrix = g.matrix()?;
198                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
199                        }
200                    }
201                    "RZ" => {
202                        if let Some(g) = gate.as_any().downcast_ref::<single::RotationZ>() {
203                            let matrix = g.matrix()?;
204                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
205                        }
206                    }
207                    "S" => {
208                        if let Some(g) = gate.as_any().downcast_ref::<single::Phase>() {
209                            let matrix = g.matrix()?;
210                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
211                        }
212                    }
213                    "T" => {
214                        if let Some(g) = gate.as_any().downcast_ref::<single::T>() {
215                            let matrix = g.matrix()?;
216                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
217                        }
218                    }
219
220                    // Two-qubit gates
221                    "CNOT" => {
222                        if let Some(g) = gate.as_any().downcast_ref::<multi::CNOT>() {
223                            state_vector
224                                .apply_cnot(g.control.id() as usize, g.target.id() as usize);
225                        }
226                    }
227                    "CZ" => {
228                        if let Some(g) = gate.as_any().downcast_ref::<multi::CZ>() {
229                            let matrix = g.matrix()?;
230                            state_vector.apply_two_qubit_gate(
231                                &matrix,
232                                g.control.id() as usize,
233                                g.target.id() as usize,
234                            );
235                        }
236                    }
237                    "SWAP" => {
238                        if let Some(g) = gate.as_any().downcast_ref::<multi::SWAP>() {
239                            let matrix = g.matrix()?;
240                            state_vector.apply_two_qubit_gate(
241                                &matrix,
242                                g.qubit1.id() as usize,
243                                g.qubit2.id() as usize,
244                            );
245                        }
246                    }
247
248                    // Three-qubit gates are not directly supported yet
249                    "Toffoli" | "Fredkin" => {
250                        return Err(QuantRS2Error::UnsupportedOperation(
251                            format!("Direct {} gate not yet implemented in optimized simulator. Use gate decomposition.", gate.name())
252                        ));
253                    }
254
255                    _ => {
256                        return Err(QuantRS2Error::UnsupportedOperation(format!(
257                            "Gate {} not supported in optimized simulator",
258                            gate.name()
259                        )));
260                    }
261                }
262            }
263
264            // Create register from final state
265            Register::<N>::with_amplitudes(state_vector.state().to_vec())
266        }
267    }
268}
quantrs2_sim/optimized_simulator_chunked.rs

quantrs2_sim/
optimized_simulator_chunked.rs
