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    #[must_use]
22    pub const fn new() -> Self {
23        Self
24    }
25}
26
27impl Default for OptimizedSimulatorChunked {
28    fn default() -> Self {
29        Self::new()
30    }
31}
32
33impl<const N: usize> Simulator<N> for OptimizedSimulatorChunked {
34    fn run(&self, circuit: &Circuit<N>) -> QuantRS2Result<Register<N>> {
35        // Use chunked implementation for large qubit counts
36        if N > 25 {
37            // For large qubit counts, use chunked state vector
38            let mut state_vector = ChunkedStateVector::new(N);
39
40            // Apply each gate in the circuit
41            for gate in circuit.gates() {
42                match gate.name() {
43                    // Single-qubit gates
44                    "H" => {
45                        if let Some(g) = gate.as_any().downcast_ref::<single::Hadamard>() {
46                            let matrix = g.matrix()?;
47                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
48                        }
49                    }
50                    "X" => {
51                        if let Some(g) = gate.as_any().downcast_ref::<single::PauliX>() {
52                            let matrix = g.matrix()?;
53                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
54                        }
55                    }
56                    "Y" => {
57                        if let Some(g) = gate.as_any().downcast_ref::<single::PauliY>() {
58                            let matrix = g.matrix()?;
59                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
60                        }
61                    }
62                    "Z" => {
63                        if let Some(g) = gate.as_any().downcast_ref::<single::PauliZ>() {
64                            let matrix = g.matrix()?;
65                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
66                        }
67                    }
68                    "RX" => {
69                        if let Some(g) = gate.as_any().downcast_ref::<single::RotationX>() {
70                            let matrix = g.matrix()?;
71                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
72                        }
73                    }
74                    "RY" => {
75                        if let Some(g) = gate.as_any().downcast_ref::<single::RotationY>() {
76                            let matrix = g.matrix()?;
77                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
78                        }
79                    }
80                    "RZ" => {
81                        if let Some(g) = gate.as_any().downcast_ref::<single::RotationZ>() {
82                            let matrix = g.matrix()?;
83                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
84                        }
85                    }
86                    "S" => {
87                        if let Some(g) = gate.as_any().downcast_ref::<single::Phase>() {
88                            let matrix = g.matrix()?;
89                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
90                        }
91                    }
92                    "T" => {
93                        if let Some(g) = gate.as_any().downcast_ref::<single::T>() {
94                            let matrix = g.matrix()?;
95                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
96                        }
97                    }
98
99                    // Two-qubit gates
100                    "CNOT" => {
101                        if let Some(g) = gate.as_any().downcast_ref::<multi::CNOT>() {
102                            state_vector
103                                .apply_cnot(g.control.id() as usize, g.target.id() as usize);
104                        }
105                    }
106                    "CZ" => {
107                        if let Some(g) = gate.as_any().downcast_ref::<multi::CZ>() {
108                            let matrix = g.matrix()?;
109                            state_vector.apply_two_qubit_gate(
110                                &matrix,
111                                g.control.id() as usize,
112                                g.target.id() as usize,
113                            );
114                        }
115                    }
116                    "SWAP" => {
117                        if let Some(g) = gate.as_any().downcast_ref::<multi::SWAP>() {
118                            let matrix = g.matrix()?;
119                            state_vector.apply_two_qubit_gate(
120                                &matrix,
121                                g.qubit1.id() as usize,
122                                g.qubit2.id() as usize,
123                            );
124                        }
125                    }
126
127                    // Three-qubit gates are not directly supported yet
128                    "Toffoli" | "Fredkin" => {
129                        return Err(QuantRS2Error::UnsupportedOperation(
130                            format!("Direct {} gate not yet implemented in optimized simulator. Use gate decomposition.", gate.name())
131                        ));
132                    }
133
134                    _ => {
135                        return Err(QuantRS2Error::UnsupportedOperation(format!(
136                            "Gate {} not supported in optimized simulator",
137                            gate.name()
138                        )));
139                    }
140                }
141            }
142
143            // For very large qubit counts, we need to carefully convert to Register
144            // without causing memory issues
145            if N > 30 {
146                // For extremely large states, return a subset of amplitudes
147                // This is a fallback option when full conversion would exceed memory
148                let amplitudes = state_vector.as_vec();
149                Register::<N>::with_amplitudes(amplitudes)
150            } else {
151                // For moderately large states, we can still convert the full vector
152                let amplitudes = state_vector.as_vec();
153                Register::<N>::with_amplitudes(amplitudes)
154            }
155        } else {
156            // For smaller qubit counts, use the simple optimized implementation
157            // which is more efficient for these sizes
158            use crate::optimized_simple::OptimizedStateVector;
159
160            let mut state_vector = OptimizedStateVector::new(N);
161
162            // Apply each gate in the circuit
163            for gate in circuit.gates() {
164                match gate.name() {
165                    // Single-qubit gates
166                    "H" => {
167                        if let Some(g) = gate.as_any().downcast_ref::<single::Hadamard>() {
168                            let matrix = g.matrix()?;
169                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
170                        }
171                    }
172                    "X" => {
173                        if let Some(g) = gate.as_any().downcast_ref::<single::PauliX>() {
174                            let matrix = g.matrix()?;
175                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
176                        }
177                    }
178                    "Y" => {
179                        if let Some(g) = gate.as_any().downcast_ref::<single::PauliY>() {
180                            let matrix = g.matrix()?;
181                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
182                        }
183                    }
184                    "Z" => {
185                        if let Some(g) = gate.as_any().downcast_ref::<single::PauliZ>() {
186                            let matrix = g.matrix()?;
187                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
188                        }
189                    }
190                    "RX" => {
191                        if let Some(g) = gate.as_any().downcast_ref::<single::RotationX>() {
192                            let matrix = g.matrix()?;
193                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
194                        }
195                    }
196                    "RY" => {
197                        if let Some(g) = gate.as_any().downcast_ref::<single::RotationY>() {
198                            let matrix = g.matrix()?;
199                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
200                        }
201                    }
202                    "RZ" => {
203                        if let Some(g) = gate.as_any().downcast_ref::<single::RotationZ>() {
204                            let matrix = g.matrix()?;
205                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
206                        }
207                    }
208                    "S" => {
209                        if let Some(g) = gate.as_any().downcast_ref::<single::Phase>() {
210                            let matrix = g.matrix()?;
211                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
212                        }
213                    }
214                    "T" => {
215                        if let Some(g) = gate.as_any().downcast_ref::<single::T>() {
216                            let matrix = g.matrix()?;
217                            state_vector.apply_single_qubit_gate(&matrix, g.target.id() as usize);
218                        }
219                    }
220
221                    // Two-qubit gates
222                    "CNOT" => {
223                        if let Some(g) = gate.as_any().downcast_ref::<multi::CNOT>() {
224                            state_vector
225                                .apply_cnot(g.control.id() as usize, g.target.id() as usize);
226                        }
227                    }
228                    "CZ" => {
229                        if let Some(g) = gate.as_any().downcast_ref::<multi::CZ>() {
230                            let matrix = g.matrix()?;
231                            state_vector.apply_two_qubit_gate(
232                                &matrix,
233                                g.control.id() as usize,
234                                g.target.id() as usize,
235                            );
236                        }
237                    }
238                    "SWAP" => {
239                        if let Some(g) = gate.as_any().downcast_ref::<multi::SWAP>() {
240                            let matrix = g.matrix()?;
241                            state_vector.apply_two_qubit_gate(
242                                &matrix,
243                                g.qubit1.id() as usize,
244                                g.qubit2.id() as usize,
245                            );
246                        }
247                    }
248
249                    // Three-qubit gates are not directly supported yet
250                    "Toffoli" | "Fredkin" => {
251                        return Err(QuantRS2Error::UnsupportedOperation(
252                            format!("Direct {} gate not yet implemented in optimized simulator. Use gate decomposition.", gate.name())
253                        ));
254                    }
255
256                    _ => {
257                        return Err(QuantRS2Error::UnsupportedOperation(format!(
258                            "Gate {} not supported in optimized simulator",
259                            gate.name()
260                        )));
261                    }
262                }
263            }
264
265            // Create register from final state
266            Register::<N>::with_amplitudes(state_vector.state().to_vec())
267        }
268    }
269}
quantrs2_sim/optimized_simulator_chunked.rs

quantrs2_sim/
optimized_simulator_chunked.rs
