l1d-optimization\l1d-optimization.rs

/// # Arguments
///
/// * `n` - The dimension of the matrix.
/// 
/// # Returns a matrix with values from 0 to n - 1.
/// Initializes a matrix with values from 0 to n - 1.
pub fn generate_matrix(n: usize) -> Vec<Vec<f64>> {
    let mut matrix = vec![vec![0.0; n]; n];
    let mut value = 0.0;
    for r in 0..n {
        for c in 0..n {
            matrix[r][c] = value;
            value += 1.0;
        }
    }

    matrix
}

/// Returns the result of a matrix multiplication.
/// It transpose the second matrix to optimize the sequential memory access.
///
/// # Arguments
///
/// * `n` - The dimension of the matrix.
pub fn optimized(n: usize) -> Vec<Vec<f64>> {
    let m1 = generate_matrix(n);
    let m2 = m1.clone();

    let mut tmp = vec![vec![0.0; n]; n];
    let mut res = vec![vec![0.0; n]; n];

    // Transpose the second matrix.
    for i in 0..n {
        for j in 0..n {
            tmp[i][j] = m2[j][i];
        }
    }

    // Perform the multiplication.
    for i in 0..n {
        for j in 0..n {
            for k in 0..n {
                res[i][j] += m1[i][k] * tmp[j][k];
            }
        }
    }

    res
}