sample.rs

1use super::Lattice;2use mrlycore::errors::Result;3use mrlymath::bang::code_to_corners;45/// Returns the two lattice coordinates of each pixel centre along a row.6pub fn axes(size: usize, lattice: Lattice, row: usize) -> (Vec<f64>, Vec<f64>) {7    let inv = 1.0 / size as f64;8    let v = (row as f64 + 0.5) * inv;9    let mut a = Vec::with_capacity(size);10    let mut b = Vec::with_capacity(size);11    for col in 0..size {12        let u = (col as f64 + 0.5) * inv;13        match lattice {14            Lattice::Square => {15                a.push(u);16                b.push(v);17            }18            Lattice::Hex => {19                let sqrt3 = 3.0f64.sqrt();20                a.push(u - v / sqrt3);21                b.push(2.0 * v / sqrt3);22            }23        }24    }25    (a, b)26}2728/// Unpacks a code into its residue-corner truth table.29pub fn membership(code: u128, base: usize, dimension: usize) -> Result<Vec<bool>> {30    let corners = code_to_corners(code, dimension, base)?;31    let total = base.pow(dimension as u32);32    let mut table = vec![false; total];33    for corner in corners {34        let mut idx = 0usize;35        for &d in &corner {36            idx = idx * base + d as usize;37        }38        table[idx] = true;39    }40    Ok(table)41}4243/// Folds residues into a base-q index of the truth table.44#[inline]45pub fn pack(residues: &[usize], base: usize) -> usize {46    let mut idx = 0usize;47    for &r in residues {48        idx = idx * base + r;49    }50    idx51}5253#[cfg(test)]54mod tests {55    use super::*;56    #[test]57    fn square_axes_are_pixel_centres() {58        let (a, b) = axes(4, Lattice::Square, 0);59        assert!((a[0] - 0.125).abs() < 1e-12);60        assert!((b[0] - 0.125).abs() < 1e-12);61        assert!((a[3] - 0.875).abs() < 1e-12);62    }63    #[test]64    fn membership_matches_corners() {65        let t = membership(1, 2, 2).unwrap();66        assert_eq!(t.len(), 4);67        assert!(t[pack(&[0, 0], 2)]);68        assert!(!t[pack(&[1, 1], 2)]);69    }70    #[test]71    fn full_code_is_all_true() {72        let t = membership(15, 2, 2).unwrap();73        assert!(t.iter().all(|&x| x));74    }75}