qft/
qft.rs

1// SPDX-FileCopyrightText: 2024 Evandro Chagas Ribeiro da Rosa <evandro@quantuloop.com>
2//
3// SPDX-License-Identifier: Apache-2.0
4
5use std::f64::consts::PI;
6
7use ket::{
8    controlled_gate,
9    error::KetError,
10    ir::{
11        block::BasicBlock,
12        gate::{Param, QuantumGate},
13    },
14    process::{Process, QPUConfig},
15    swap_gate,
16};
17
18fn qft(qubits: &[usize], do_swap: bool) -> Result<BasicBlock, KetError> {
19    let mut quantum_code = BasicBlock::new();
20    if qubits.len() == 1 {
21        quantum_code.append_gate(QuantumGate::Hadamard, qubits[0]);
22        return Ok(quantum_code);
23    }
24
25    let init = &qubits[..qubits.len() - 1];
26    let last = qubits[qubits.len() - 1];
27    quantum_code.append_gate(QuantumGate::Hadamard, last);
28    for (i, c) in init.iter().enumerate() {
29        quantum_code.append_block(
30            controlled_gate(
31                QuantumGate::Phase(Param::Value(PI / 2.0_f64.powi(i as i32 + 1))),
32                &[*c],
33                last,
34            )?,
35            None,
36        );
37    }
38    quantum_code.append_block(qft(init, false)?, None);
39
40    if do_swap {
41        for i in 0..qubits.len() / 2 {
42            quantum_code.append_block(swap_gate(qubits[i], qubits[qubits.len() - i - 1])?, None);
43        }
44    }
45
46    Ok(quantum_code)
47}
48
49fn main() -> Result<(), KetError> {
50    let num_qubits = 12;
51
52    let mut process = Process::new(QPUConfig {
53        num_qubits,
54        quantum_execution: None,
55    });
56
57    let qubits: Result<Vec<_>, _> = (0..num_qubits).map(|_| process.alloc()).collect();
58    let qubits = qubits?;
59
60    process.append_block(qft(&qubits, true)?)?;
61
62    println!("{:#?}", process);
63
64    Ok(())
65}
qft/qft.rs

qft/
qft.rs
