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extern crate itertools;
use num_traits::Signed;
use std::ops::{Index, IndexMut, Neg, Range};
/// Matrix of an arbitrary type. Data are stored consecutively in
/// memory, by rows. Raw data can be accessed using `as_ref()`
/// or `as_mut()`.
#[derive(Clone, Debug, Eq, Hash, PartialEq)]
pub struct Matrix<C> {
/// Rows
pub rows: usize,
/// Columns
pub columns: usize,
data: Vec<C>,
}
unsafe impl<C: Send> Send for Matrix<C> {}
impl<C: Clone> Matrix<C> {
/// Create new matrix with an initial value.
pub fn new(rows: usize, columns: usize, value: C) -> Matrix<C> {
let mut v = Vec::with_capacity(rows * columns);
v.resize(rows * columns, value);
Matrix {
rows: rows,
columns: columns,
data: v,
}
}
/// Create new square matrix with initial value.
pub fn new_square(size: usize, value: C) -> Matrix<C> {
Self::new(size, size, value)
}
/// Fill with a known value.
pub fn fill(&mut self, value: C) {
self.data.clear();
self.data.resize(self.rows * self.columns, value);
}
/// Return a copy of a sub-matrix.
#[cfg_attr(feature = "cargo-clippy", allow(needless_pass_by_value))]
pub fn slice(&self, rows: Range<usize>, columns: Range<usize>) -> Matrix<C> {
let height = rows.end - rows.start;
let width = columns.end - columns.start;
let mut v = Vec::with_capacity(height * width);
for r in rows {
v.extend(
self.data[r * self.columns + columns.start..r * self.columns + columns.end]
.iter()
.cloned(),
);
}
Matrix::from_vec(height, width, v)
}
/// Return a copy of a square matrix rotated clock-wise
/// a number of times.
///
/// # Panics
///
/// This function panics if the matrix is not square.
pub fn rotated_cw(&self, times: usize) -> Matrix<C> {
let mut copy = self.clone();
copy.rotate_cw(times);
copy
}
/// Return a copy of a square matrix rotated counter-clock-wise
/// a number of times.
///
/// # Panics
///
/// This function panics if the matrix is not square.
pub fn rotated_ccw(&self, times: usize) -> Matrix<C> {
let mut copy = self.clone();
copy.rotate_ccw(times);
copy
}
/// Return a copy of the matrix flipped along the vertical axis.
pub fn flipped_lr(&self) -> Matrix<C> {
let mut copy = self.clone();
copy.flip_lr();
copy
}
/// Return a copy of the matrix flipped along the horizontal axis.
pub fn flipped_ud(&self) -> Matrix<C> {
let mut copy = self.clone();
copy.flip_ud();
copy
}
/// Return a copy of the matrix after transposition.
pub fn transposed(&self) -> Matrix<C> {
Matrix {
rows: self.columns,
columns: self.rows,
data: iproduct!(0..self.columns, 0..self.rows)
.map(|(c, r)| self.data[r * self.columns + c].clone())
.collect(),
}
}
}
impl<C: Copy> Matrix<C> {
/// Replace a slice of the current matrix with the content of another one.
pub fn set_slice(&mut self, pos: &(usize, usize), slice: &Matrix<C>) {
let &(ref row, ref column) = pos;
let height = (self.rows - row).min(slice.rows);
let width = (self.columns - column).min(slice.columns);
for r in 0..height {
self.data[(row + r) * self.columns + column..(row + r) * self.columns + column + width]
.copy_from_slice(&slice.data[r * slice.columns..r * slice.columns + width]);
}
}
}
impl<C: Clone + Signed> Neg for Matrix<C> {
type Output = Matrix<C>;
fn neg(self) -> Matrix<C> {
Matrix {
rows: self.rows,
columns: self.columns,
data: self.data.iter().map(|x| -x.clone()).collect::<Vec<_>>(),
}
}
}
impl<C> Matrix<C> {
/// Create new matrix from vector values. The first value
/// will be assigned to index (0, 0), the second one to index (0, 1),
/// and so on.
///
/// # Panics
///
/// This function will panic if the number of values does not correspond
/// to the announced size.
pub fn from_vec(rows: usize, columns: usize, values: Vec<C>) -> Matrix<C> {
assert_eq!(
rows * columns,
values.len(),
"length of vector does not correspond to announced dimensions"
);
Matrix {
rows: rows,
columns: columns,
data: values,
}
}
/// Create new square matrix from vector values. The first value
/// will be assigned to index (0, 0), the second one to index (0, 1),
/// and so on.
///
/// # Panics
///
/// This function will panic if the number of values is not a square number.
pub fn square_from_vec(values: Vec<C>) -> Matrix<C> {
let size = (values.len() as f32).sqrt().round() as usize;
assert_eq!(
size * size,
values.len(),
"length of vector is not a square number"
);
Self::from_vec(size, size, values)
}
/// Check if a matrix is a square one.
pub fn is_square(&self) -> bool {
self.rows == self.columns
}
/// Index in raw data of a given position.
pub fn idx(&self, i: &(usize, usize)) -> usize {
i.0 * self.columns + i.1
}
/// Flip the matrix around the vertical axis.
pub fn flip_lr(&mut self) {
for r in 0..self.rows {
self.data[r * self.columns..(r + 1) * self.columns].reverse();
}
}
/// Flip the matrix around the horizontal axis.
pub fn flip_ud(&mut self) {
for r in 0..self.rows / 2 {
for c in 0..self.columns {
self.data
.swap(r * self.columns + c, (self.rows - 1 - r) * self.columns + c);
}
}
}
/// Rotate a square matrix clock-wise a number of times.
///
/// # Panics
///
/// This function panics if the matrix is not square.
pub fn rotate_cw(&mut self, times: usize) {
assert!(
self.rows == self.columns,
"attempt to rotate a non-square matrix"
);
match times % 4 {
0 => (),
2 => self.data.reverse(),
n => {
for r in 0..self.rows / 2 {
for c in 0..(self.columns + 1) / 2 {
// i1 … i2
// … … …
// i4 … i3
let i1 = r * self.columns + c;
let i2 = c * self.columns + self.columns - 1 - r;
let i3 = (self.rows - 1 - r) * self.columns + self.columns - 1 - c;
let i4 = (self.rows - 1 - c) * self.columns + r;
if n == 1 {
// i1 … i2 i4 … i1
// … … … => … … …
// i4 … i3 i3 … i2
self.data.swap(i1, i2);
self.data.swap(i1, i4);
self.data.swap(i3, i4);
} else {
// i1 … i2 i2 … i3
// … … … => … … …
// i4 … i3 i1 … i4
self.data.swap(i3, i4);
self.data.swap(i1, i4);
self.data.swap(i1, i2);
}
}
}
}
}
}
/// Rotate a square matrix counter-clock-wise a number of times.
///
/// # Panics
///
/// This function panics if the matrix is not square.
pub fn rotate_ccw(&mut self, times: usize) {
self.rotate_cw(4 - (times % 4))
}
}
impl<'a, C> Index<&'a (usize, usize)> for Matrix<C> {
type Output = C;
fn index(&self, index: &'a (usize, usize)) -> &C {
&self.data[self.idx(index)]
}
}
impl<'a, C> IndexMut<&'a (usize, usize)> for Matrix<C> {
fn index_mut(&mut self, index: &'a (usize, usize)) -> &mut C {
let i = self.idx(index);
&mut self.data[i]
}
}
impl<C> AsRef<[C]> for Matrix<C> {
fn as_ref(&self) -> &[C] {
&self.data
}
}
impl<C> AsMut<[C]> for Matrix<C> {
fn as_mut(&mut self) -> &mut [C] {
&mut self.data
}
}