Macro sortnet::gen_sortnet

macro_rules! gen_sortnet {
    ($fsort:ident, $n:expr, [$([$(($swap_a:expr, $swap_b:expr)),+]),*]) => { ... };
}

Create new sortnet implementation.

Takes the following arguments:

• fsort: name of the public function that gets created
• n: number of elements in the array
• swaps: elements to be compared in order. Must be grouped by operations that can be executed in parallel.

Example

We want to create a new sortnet for 4 elements that looks like this:

o o o o
| | | |
+-+ +-+
| | | |
+---+ |
| | | |
| +---+
| | | |
| +-+ |
| | | |
V V V V

There are 5 compare-and-swap operations:

• 0 and 1
• 2 and 3
• 0 and 2
• 1 and 3
• 1 and 2

These can be grouped in the following way so that they that elements within a group can be executed in parallel:

• (0 and 1), (2 and 3)
• (0 and 2), (1 and 3)
• (1 and 2)

In code, this looks like this:

use sortnet::gen_sortnet;

gen_sortnet!(my_sortnet, 4, [[(0, 1), (2, 3)], [(0, 2), (1, 3)], [(1, 2)]]);

let mut data = [0, 13, -1, 2];
my_sortnet(&mut data);
assert_eq!(data, [-1, 0, 2, 13]);

Requirements

Ther are a few compile-time requirements to use the gen_sortnet macrol

Non-empty Groups

Groups must not be empty:

use sortnet::gen_sortnet;

gen_sortnet!(my_sortnet, 3, [[], [(1, 2)], [(0, 2)], [(0, 1)]]);

Non-negative Size

The array size must not be negative:

use sortnet::gen_sortnet;

gen_sortnet!(my_sortnet, -1, []);

Non-negative Indices

Sortnet indices must not be negative:

use sortnet::gen_sortnet;

gen_sortnet!(my_sortnet, 3, [[(1, 2)], [(0, 2)], [(0, -1)]]);

In-bounds Indices

Sortnet indices must not be out-of bounds:

use sortnet::gen_sortnet;

gen_sortnet!(my_sortnet, 3, [[(1, 2)], [(0, 2)], [(0, 3)]]);

use sortnet::gen_sortnet;

gen_sortnet!(my_sortnet, 3, [[(1, 2)], [(0, 2)], [(3, 1)]]);