qnect 0.3.0

⚛ Quantum computing in Rust: from Bell pairs to distributed quantum networks.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156

use crate::error::{QnectError, Result};
use crate::quantum::system::QuantumSystem;
use crate::utils::qasm_parser::QasmOperation;
use crate::{
    backend::{
        backend::QuantumBackend,
        mock_qnpu::MockQnpuBackend,
        network_backend::{NetworkBackend, NetworkTopology},
        noisy::NoisyBackend,
        stabilizer::StabilizerBackend,
        state_vector::StateVectorBackend,
    },
    utils::qasm_parser::parse_qasm,
};

/// Fluent API for building quantum systems
pub struct QuantumSystemBuilder {
    backend_type: BackendType,
    qubit_count: Option<usize>,
    topology: Option<NetworkTopology>,
    noise_model: Option<NoiseModel>,
}

#[derive(Debug, Clone)]
pub enum BackendType {
    StateVector,
    Network,
    Stabilizer,
    MockQnpu { endpoint: String, node_id: String },
    TensorNetwork, // Future
}

#[derive(Debug, Clone)]
pub struct NoiseModel {
    pub depolarizing_rate: f64, // Probability of error per gate
    pub measurement_error: f64, // Probability of measurement flip
}

impl QuantumSystemBuilder {
    pub fn new() -> Self {
        QuantumSystemBuilder {
            backend_type: BackendType::StateVector,
            qubit_count: None,
            topology: None,
            noise_model: None,
        }
    }

    pub fn with_noise(mut self, noise_model: NoiseModel) -> Self {
        self.noise_model = Some(noise_model);
        self
    }

    pub fn with_qubits(mut self, n: usize) -> Self {
        self.qubit_count = Some(n);
        self
    }

    pub fn with_backend(mut self, backend: BackendType) -> Self {
        self.backend_type = backend;
        self
    }

    pub fn with_topology(mut self, topology: NetworkTopology) -> Self {
        self.topology = Some(topology);
        self
    }

    /// Create a quantum system builder from a QASM string
    pub fn from_qasm(mut self, qasm: &str) -> Result<Self> {
        let program = parse_qasm(qasm)?;

        // Modify the existing builder instead of creating a new one
        self.qubit_count = Some(program.num_qubits);
        Ok(self)
    }

    pub fn build(self) -> Result<QuantumSystem<Box<dyn QuantumBackend>>> {
        let mut backend: Box<dyn QuantumBackend> = match self.backend_type {
            BackendType::StateVector => {
                Box::new(StateVectorBackend::new(self.qubit_count.unwrap_or(2)))
            }
            BackendType::Network => Box::new(NetworkBackend::new(
                self.topology.unwrap_or(NetworkTopology::AllToAll),
            )),
            BackendType::Stabilizer => {
                Box::new(StabilizerBackend::new(self.qubit_count.unwrap_or(2)))
            }
            BackendType::MockQnpu { endpoint, node_id } => {
                let backend = MockQnpuBackend::new(
                    endpoint.clone(),
                    node_id.clone(),
                    self.qubit_count.unwrap_or(2),
                );
                Box::new(backend) as Box<dyn QuantumBackend>
            }
            _ => {
                return Err(QnectError::backend_not_implemented(format!(
                    "{:?}",
                    self.backend_type
                )));
            }
        };

        // Wrap in noise if requested
        if let Some(noise) = self.noise_model {
            backend = Box::new(NoisyBackend::new(
                backend,
                noise.depolarizing_rate,
                noise.measurement_error,
            ));
        }

        Ok(QuantumSystem::new(backend))
    }
}

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

/// Execute a parsed QASM program on a quantum system
pub async fn execute_qasm<B: QuantumBackend>(
    system: &mut QuantumSystem<B>,
    qasm: &str,
) -> Result<Vec<u8>> {
    let program = parse_qasm(qasm)?;
    let mut measurements = vec![0u8; program.num_bits];

    for op in program.operations {
        match op {
            QasmOperation::H(q) => system.h(q).await?,
            QasmOperation::X(q) => system.x(q).await?,
            QasmOperation::Y(q) => system.y(q).await?,
            QasmOperation::Z(q) => system.z(q).await?,
            QasmOperation::S(q) => system.s(q).await?,
            QasmOperation::SDag(q) => system.s_dag(q).await?,
            QasmOperation::T(q) => system.t(q).await?,
            QasmOperation::TDag(q) => system.t_dag(q).await?,
            QasmOperation::Rx(q, angle) => system.rx(q, angle).await?,
            QasmOperation::Ry(q, angle) => system.ry(q, angle).await?,
            QasmOperation::Rz(q, angle) => system.rz(q, angle).await?,
            QasmOperation::CX(q1, q2) => system.cnot(q1, q2).await?,
            QasmOperation::CY(q1, q2) => system.cy(q1, q2).await?,
            QasmOperation::CZ(q1, q2) => system.cz(q1, q2).await?,
            QasmOperation::Swap(q1, q2) => system.swap(q1, q2).await?,
            QasmOperation::Measure(qubit, bit) => {
                measurements[bit] = system.measure(qubit).await?;
            }
        }
    }

    Ok(measurements)
}