Q-Rust

A quantum transpiler written in Rust, designed to parse, analyze, and optimize quantum circuits.

Features

Robust QASM 2.0 Support: Parse OpenQASM 2.0 files with full support for standard gates, parameterized rotations, and measurements.
Modular Intermediate Representation (IR): A flexible, type-safe IR built for easy analysis and transformation.
Graph-Based Backend Topology: Define custom hardware backends with arbitrary connectivity using efficient graph structures (petgraph).

Error Handling

Q-Rust enforces strict OpenQASM 2.0 compliance. It will explicitly reject:

OpenQASM 3.0: Files starting with OPENQASM 3.0; will trigger an Unsupported OpenQASM version error.
Missing Headers: Files must start with a valid OPENQASM 2.0; header.
Missing Measurements: The Circuit::validate() method warns if a circuit has no measurements, as it will not produce output on real hardware.

Installation

Add to your Cargo.toml:

[dependencies]
q-rust = "0.1"

Usage

Parsing QASM

use q_rust::parser::parse_qasm;

fn main() {
    let qasm_code = r#"
        OPENQASM 2.0;
        include "qelib1.inc";
        qreg q[2];
        creg c[2];
        h q[0];
        cx q[0], q[1];
        measure q[1] -> c[1];
    "#;

    match parse_qasm(qasm_code) {
        Ok(circuit) => {
            println!("Successfully parsed circuit with {} operations.", circuit.operations.len());
            println!("Qubits: {}, Classical Bits: {}", circuit.num_qubits, circuit.num_cbits);
        }
        Err(e) => eprintln!("Error parsing QASM: {}", e),
    }
}

Defining a Backend

use q_rust::backend::Backend;

fn main() {
    let mut backend = Backend::new("MyQuantumMachine".to_string(), 5);
    
    // Define connectivity (0 -> 1 -> 2)
    backend.set_coupling_map(vec![(0, 1), (1, 2)]);
    
    println!("Backend {} has {} qubits.", backend.name, backend.num_qubits);
}

References

This project adheres to the OpenQASM 2.0 specification:

Specification: OpenQASM 2.0 on GitHub
Paper: Andrew W. Cross, Lev S. Bishop, John A. Smolin, Jay M. Gambetta, "Open Quantum Assembly Language", arXiv:1707.03429

License

MIT or Apache-2.0

q-rust 0.1.1