RustQIP

Quantum Computing library leveraging graph building to build efficient quantum circuit simulations.

See all the examples in the examples directory of the Github repository.

Example (CSWAP)

Here's an example of a small circuit where two groups of qubits are swapped conditioned on a third. This circuit is very small, only three operations plus a measurement, so the boilerplate can look quite large in compairison, but that setup provides the ability to construct circuits easily and safely when they do get larger.

use qip::*;

// Make a new circuit builder.
let mut b = OpBuilder::new();

// Make three logical groups of qubits of sizes 1, 3, 3 (7 qubits total).
let q = b.qubit(1)?;
let qa = b.qubit(3)?;
let qb = b.qubit(3)?;

// We will want to feed in some inputs later, hang on to the handles
// so we don't need to actually remember any indices.
let a_handle = qa.handle();
let b_handle = qb.handle();

// Define circuit
// First apply an H to q1
let q = b.hadamard(q);
// Then run this subcircuit conditioned on q, applied to qa and qb
let (q, _) = condition(&mut b, q, (qa, qb), |c, (qa, qb)| {
    c.swap(qa, qb)
})?;
// Finally apply H to q again.
let q = b.hadamard(q);

// Add a measurement to the first qubit, save a reference so we can get the result later.
let (q, m_handle) = b.measure(q);

// Now q is the end result of the above circuit, and we can run the circuit by referencing it.

// Make an initial state: |0,000,001>
let initial_state = [a_handle.make_init_from_index(0)?,
                     b_handle.make_init_from_index(1)?];
// Run circuit with a given precision.
let (_, measured) = run_local_with_init::<f64>(&q, &initial_state)?;

// Lookup the result of the measurement we performed using the handle.
let (result, p) = measured.get_measurement(&m_handle).unwrap();

// Print the measured result
println!("Measured: {:?} (with chance {:?})", result, p);