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#![allow(
clippy::many_single_char_names, clippy::deref_addrof, clippy::unreadable_literal, clippy::many_single_char_names
)]
use ndarray::prelude::*;
use ndarray::Zip;
fn main()
{
let n = 6;
let mut a = Array::<f32, _>::zeros((n, n));
let mut b = Array::<f32, _>::zeros((n, n));
for ((i, j), elt) in b.indexed_iter_mut() {
*elt = 1. / (1. + (i + 2 * j) as f32);
}
let c = Array::<f32, _>::from_elem((n, n + 1), 1.7);
let c = c.slice(s![.., ..-1]);
// Using Zip for arithmetic ops across a, b, c
Zip::from(&mut a)
.and(&b)
.and(&c)
.for_each(|a, &b, &c| *a = b + c);
assert_eq!(a, &b + &c);
// and this is how to do the *same thing* with azip!()
azip!((a in &mut a, &b in &b, &c in c) *a = b + c);
println!("{:8.4}", a);
// sum of each row
let mut sums = Array::zeros(a.nrows());
Zip::from(a.rows())
.and(&mut sums)
.for_each(|row, sum| *sum = row.sum());
// show sums as a column matrix
println!("{:8.4}", sums.insert_axis(Axis(1)));
// sum of each 2x2 chunk
let chunk_sz = (2, 2);
let nchunks = (n / chunk_sz.0, n / chunk_sz.1);
let mut sums = Array::zeros(nchunks);
Zip::from(a.exact_chunks(chunk_sz))
.and(&mut sums)
.for_each(|chunk, sum| *sum = chunk.sum());
println!("{:8.4}", sums);
}
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