1use ark_ff::PrimeField;
 2use ark_std::cfg_iter;
 3
 4#[derive(Clone, Debug, Eq, PartialEq)]
 5pub struct SparseMatrix<F: PrimeField> {
 6    pub n_rows: usize,
 7    pub n_cols: usize,
 8    pub coeffs: Vec<(usize, usize, F)>,
 9}
10
11pub fn dense_matrix_to_sparse<F: PrimeField>(m: Vec<Vec<F>>) -> SparseMatrix<F> {
12    let mut r = SparseMatrix::<F> {
13        n_rows: m.len(),
14        n_cols: m[0].len(),
15        coeffs: Vec::new(),
16    };
17    for (i, m_i) in m.iter().enumerate() {
18        for (j, m_ij) in m_i.iter().enumerate() {
19            if !m_ij.is_zero() {
20                r.coeffs.push((i, j, *m_ij));
21            }
22        }
23    }
24    r
25}
26
27pub fn vec_add<F: PrimeField>(a: &[F], b: &[F]) -> Vec<F> {
28    assert_eq!(a.len(), b.len());
29    let mut r: Vec<F> = vec![F::zero(); a.len()];
30    for i in 0..a.len() {
31        r[i] = a[i] + b[i];
32    }
33    r
34}
35
36pub fn vec_sub<F: PrimeField>(a: &[F], b: &[F]) -> Vec<F> {
37    assert_eq!(a.len(), b.len());
38    let mut r: Vec<F> = vec![F::zero(); a.len()];
39    for i in 0..a.len() {
40        r[i] = a[i] - b[i];
41    }
42    r
43}
44
45pub fn vec_scalar_mul<F: PrimeField>(vec: &[F], c: &F) -> Vec<F> {
46    let mut result = vec![F::zero(); vec.len()];
47    for (i, a) in vec.iter().enumerate() {
48        result[i] = *a * c;
49    }
50    result
51}
52
53pub fn is_zero_vec<F: PrimeField>(vec: &[F]) -> bool {
54    for e in vec {
55        if !e.is_zero() {
56            return false;
57        }
58    }
59    true
60}
61
62pub fn mat_vec_mul<F: PrimeField>(M: &Vec<Vec<F>>, z: &[F]) -> Vec<F> {
63    assert!(!M.is_empty());
64    assert_eq!(M[0].len(), z.len());
65
66    let mut r: Vec<F> = vec![F::zero(); M.len()];
67    for (i, M_i) in M.iter().enumerate() {
68        for (j, M_ij) in M_i.iter().enumerate() {
69            r[i] += *M_ij * z[j];
70        }
71    }
72    r
73}
74
75pub fn mat_vec_mul_sparse<F: PrimeField>(matrix: &SparseMatrix<F>, vector: &[F]) -> Vec<F> {
76    let mut res = vec![F::zero(); matrix.n_cols];
77    for &(row, col, value) in matrix.coeffs.iter() {
78        res[row] += value * vector[col];
79    }
80    res
81}
82
83pub fn hadamard<F: PrimeField>(a: &[F], b: &[F]) -> Vec<F> {
84    assert_eq!(a.len(), b.len());
85    cfg_iter!(a).zip(b).map(|(a, b)| *a * b).collect()
86}