cqlib-core 0.1.0-beta.7

The high-performance core foundation for the CQLib quantum computing ecosystem.
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

// This code is part of Cqlib.
//
// (C) Copyright China Telecom Quantum Group 2026
//
// This code is licensed under the Apache License, Version 2.0. You may
// obtain a copy of this license in the LICENSE.txt file in the root directory
// of this source tree or at http://www.apache.org/licenses/LICENSE-2.0.
//
// Any modifications or derivative works of this code must retain this
// copyright notice, and modified files need to carry a notice indicating
// that they have been altered from the originals.

//! Shared matrix and circuit assertions for crate-local tests.

use super::{Circuit, circuit_to_matrix};
use ndarray::Array2;
use num_complex::Complex64;

/// Asserts approximate equality of complete matrices.
pub(crate) fn assert_matrix_approx_eq(
    actual: &Array2<Complex64>,
    expected: &Array2<Complex64>,
    epsilon: f64,
) {
    assert_eq!(actual.shape(), expected.shape());
    for ((row, column), expected_amplitude) in expected.indexed_iter() {
        assert!(
            (actual[[row, column]] - expected_amplitude).norm() < epsilon,
            "matrix mismatch at row {row}, column {column}: actual={}, expected={expected_amplitude}",
            actual[[row, column]]
        );
    }
}

/// Asserts that a matrix is unitary: U† * U = I.
pub(crate) fn assert_is_unitary(matrix: &Array2<Complex64>, epsilon: f64) {
    assert_eq!(
        matrix.nrows(),
        matrix.ncols(),
        "unitary matrix must be square, got {}x{}",
        matrix.nrows(),
        matrix.ncols()
    );

    let product = matrix.t().mapv(|value| value.conj()).dot(matrix);
    for row in 0..matrix.nrows() {
        for column in 0..matrix.ncols() {
            let expected = if row == column {
                Complex64::new(1.0, 0.0)
            } else {
                Complex64::new(0.0, 0.0)
            };
            let diff = (product[[row, column]] - expected).norm();
            assert!(
                diff < epsilon,
                "matrix is not unitary at row {row}, column {column}: actual={}, expected={expected}, diff={diff}",
                product[[row, column]]
            );
        }
    }
}

/// Asserts that two matrices are equal up to one global phase.
pub(crate) fn assert_matrices_equal_up_to_global_phase(
    actual: &Array2<Complex64>,
    expected: &Array2<Complex64>,
    epsilon: f64,
) {
    assert_eq!(actual.shape(), expected.shape());
    let (reference_actual, reference_expected) = actual
        .iter()
        .zip(expected.iter())
        .find(|(_, expected)| expected.norm() > epsilon)
        .expect("expected matrix must contain a nonzero amplitude");
    assert!(
        reference_actual.norm() > epsilon,
        "actual matrix has zero amplitude where expected matrix is nonzero"
    );

    let global_phase = reference_actual / reference_expected;
    assert!(
        (global_phase.norm() - 1.0).abs() < epsilon,
        "matrices differ in reference amplitude magnitude: actual={reference_actual}, expected={reference_expected}"
    );

    for ((row, column), expected_amplitude) in expected.indexed_iter() {
        let phase_adjusted_expected = global_phase * expected_amplitude;
        assert!(
            (actual[[row, column]] - phase_adjusted_expected).norm() < epsilon,
            "matrix mismatch at row {row}, column {column}: actual={}, expected={phase_adjusted_expected}",
            actual[[row, column]]
        );
    }
}

/// Asserts that two circuits have the same unitary matrix up to global phase.
pub(crate) fn assert_circuits_equivalent_up_to_global_phase(
    actual: &Circuit,
    expected: &Circuit,
    epsilon: f64,
) {
    let actual_matrix = circuit_to_matrix(actual, None).unwrap();
    let expected_matrix = circuit_to_matrix(expected, None).unwrap();
    assert_matrices_equal_up_to_global_phase(&actual_matrix, &expected_matrix, epsilon);
}

/// Returns whether two matrices are equal up to one global phase.
///
/// Non-panicking counterpart of [`assert_matrices_equal_up_to_global_phase`],
/// for negative assertions that must not emit panic-hook output.
pub(crate) fn matrices_equal_up_to_global_phase(
    actual: &Array2<Complex64>,
    expected: &Array2<Complex64>,
    epsilon: f64,
) -> bool {
    if actual.shape() != expected.shape() {
        return false;
    }
    let Some((reference_actual, reference_expected)) = actual
        .iter()
        .zip(expected.iter())
        .find(|(_, expected)| expected.norm() > epsilon)
    else {
        return false;
    };
    if reference_actual.norm() <= epsilon {
        return false;
    }

    let global_phase = reference_actual / reference_expected;
    if (global_phase.norm() - 1.0).abs() >= epsilon {
        return false;
    }

    actual
        .iter()
        .zip(expected.iter())
        .all(|(a, e)| (a - global_phase * e).norm() < epsilon)
}

/// Returns whether two circuits have the same unitary matrix up to global phase.
///
/// Non-panicking counterpart of [`assert_circuits_equivalent_up_to_global_phase`].
pub(crate) fn circuits_equal_up_to_global_phase(
    actual: &Circuit,
    expected: &Circuit,
    epsilon: f64,
) -> bool {
    let actual_matrix = circuit_to_matrix(actual, None).unwrap();
    let expected_matrix = circuit_to_matrix(expected, None).unwrap();
    matrices_equal_up_to_global_phase(&actual_matrix, &expected_matrix, epsilon)
}