d803bfe2b1
git-subtree-dir: vendor/ruvector git-subtree-split: b64c21726f2bb37286d9ee36a7869fef60cc6900
128 lines
3.9 KiB
Markdown
128 lines
3.9 KiB
Markdown
# ruqu-algorithms
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[](https://crates.io/crates/ruqu-algorithms)
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[](https://docs.rs/ruqu-algorithms)
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[](https://github.com/ruvnet/ruvector)
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**Production-ready quantum algorithms in Rust** — VQE for chemistry, Grover's search, QAOA optimization, and Surface Code error correction.
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## Algorithms
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| Algorithm | Use Case | Speedup |
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|-----------|----------|---------|
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| **VQE** | Molecular ground states, chemistry | Exponential for certain problems |
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| **Grover** | Unstructured database search | O(√N) vs O(N) |
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| **QAOA** | Combinatorial optimization (MaxCut) | Approximate quantum advantage |
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| **Surface Code** | Quantum error correction | Fault-tolerant computation |
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## Installation
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```bash
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cargo add ruqu-algorithms
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```
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## Variational Quantum Eigensolver (VQE)
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Find ground state energies for molecular Hamiltonians:
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```rust
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use ruqu_algorithms::vqe::{VQE, Hamiltonian, Ansatz};
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// H2 molecule Hamiltonian (simplified)
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let hamiltonian = Hamiltonian::from_pauli_strings(&[
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("ZZ", 0.5),
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("XX", 0.3),
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("YY", 0.3),
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("II", -1.0),
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]);
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// UCCSD ansatz for chemistry
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let ansatz = Ansatz::uccsd(n_qubits: 4, n_electrons: 2);
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let vqe = VQE::new(hamiltonian, ansatz);
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let result = vqe.optimize()?;
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println!("Ground state energy: {:.6} Ha", result.energy);
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```
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## Grover's Search
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Quadratic speedup for unstructured search:
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```rust
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use ruqu_algorithms::grover::{Grover, Oracle};
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// Search for |101⟩ in 3-qubit space
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let oracle = Oracle::from_target(0b101, 3);
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let grover = Grover::new(oracle);
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let result = grover.search()?;
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println!("Found: {:03b}", result); // 101
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```
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**Optimal iterations**: π/4 × √N for N items.
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## QAOA MaxCut
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Approximate solutions to NP-hard graph problems:
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```rust
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use ruqu_algorithms::qaoa::{QAOA, Graph};
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// Define graph edges
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let graph = Graph::from_edges(&[
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(0, 1), (1, 2), (2, 3), (3, 0), (0, 2)
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]);
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let qaoa = QAOA::new(graph, depth: 3);
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let result = qaoa.optimize()?;
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println!("MaxCut partition: {:?}", result.partition);
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println!("Cut value: {}", result.cut_value);
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```
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## Surface Code Error Correction
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Topological quantum error correction for fault-tolerant computing:
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```rust
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use ruqu_algorithms::surface_code::{SurfaceCode, Decoder};
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let code = SurfaceCode::new(distance: 3); // 3x3 lattice
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let decoder = Decoder::mwpm(); // Minimum-weight perfect matching
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// Encode logical qubit
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let logical_state = code.encode_logical_zero();
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// Simulate noise and correct
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let noisy = code.apply_noise(logical_state, error_rate: 0.01);
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let syndromes = code.measure_syndromes(&noisy);
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let corrected = decoder.correct(&noisy, &syndromes)?;
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```
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## Benchmarks
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| Algorithm | Qubits | Time | Hardware |
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|-----------|--------|------|----------|
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| VQE (H2) | 4 | 50ms/iteration | M2 |
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| Grover (N=1024) | 10 | 15ms | M2 |
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| QAOA (depth=3) | 8 | 100ms | M2 |
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| Surface Code (d=3) | 17 | 5ms/round | M2 |
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## Related Crates
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- [`ruqu-core`](https://crates.io/crates/ruqu-core) — Quantum circuit simulator
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- [`ruqu-exotic`](https://crates.io/crates/ruqu-exotic) — Experimental quantum-classical hybrids
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- [`ruqu-wasm`](https://crates.io/crates/ruqu-wasm) — Run in browsers via WebAssembly
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## Documentation
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- [VQE Algorithm (ADR-QE-005)](https://github.com/ruvnet/ruvector/blob/main/docs/adr/quantum-engine/ADR-QE-005-vqe-algorithm-support.md)
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- [Grover's Search (ADR-QE-006)](https://github.com/ruvnet/ruvector/blob/main/docs/adr/quantum-engine/ADR-QE-006-grover-search-implementation.md)
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- [QAOA MaxCut (ADR-QE-007)](https://github.com/ruvnet/ruvector/blob/main/docs/adr/quantum-engine/ADR-QE-007-qaoa-maxcut-implementation.md)
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- [Surface Code (ADR-QE-008)](https://github.com/ruvnet/ruvector/blob/main/docs/adr/quantum-engine/ADR-QE-008-surface-code-error-correction.md)
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## License
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MIT OR Apache-2.0
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