max.rs

    let patches = self.patches(input);

    for p in patches.iter() {
      let depth = p.data.dim().2;
      let v: Vec<f64> = (0..depth).map(|i| {
        p.data
          .slice(s![.., .., i])
          .fold(f64::NEG_INFINITY, |acc, &v| acc.max(v))
      }).collect();

      a.slice_mut(s![p.x, p.y, ..]).assign(&Array1::from(v));
    }