Struct PertaroExpert243

Source

#[repr(transparent)]
pub struct PertaroExpert243(pub Word256);

Expand description

Zero-cost view over Word256: the payload as a 5-tier micro-expert.

Tuple Fields§

§0: Word256

Implementations§

Source §

impl PertaroExpert243

Source

pub const fn seed(&self) -> u64

The seed: the word’s hash field.

Examples found in repository ?

examples/quick_start.rs (line 30)

5fn main() {
6    // 1. A 256-byte word with a seed, a parent link, and in-band sentinels.
7    let mut raw = Word256 {
8        hash: 0xcbf2_9ce4_8422_2325,
9        parent: 0,
10        trits: [0u8; 244],
11    };
12
13    // Address leaf [1, 0, 2, 1, 2] in the 5-tier ternary trie (each tier in 0..3).
14    let target_leaf = PertaroExpert243::trie_index([1, 0, 2, 1, 2]);
15    raw.trits[target_leaf] = 42; // residual override: +42 mod 243
16
17    // Stamp a defeated branch with an in-band Tombstone (245).
18    let defeated_leaf = PertaroExpert243::trie_index([2, 2, 0, 1, 0]);
19    raw.trits[defeated_leaf] = Sentinel::Tombstone as u8;
20
21    // Mark the root horizon sentinel at trits[243].
22    raw.trits[ROOT_SENTINEL] = Sentinel::NullNode as u8;
23
24    // 2. Wrap in the zero-cost view and materialize.
25    let expert = PertaroExpert243(raw);
26    let materialized: Word256 = expert.materialize();
27
28    assert!(materialized.trits[target_leaf] < MAX_PACKED);
29    assert_eq!(materialized.trits[defeated_leaf], Sentinel::Tombstone as u8);
30    assert_eq!(materialized.hash, expert.seed());
31
32    // 3. Reground the winning Tier-5 leaf (0..243) into a fresh seed.
33    let next_seed = expert.reground_seed(target_leaf as u8, Sentinel::BusIndirect);
34    assert_ne!(next_seed, expert.seed());
35
36    println!("leaf {target_leaf} -> {}", materialized.trits[target_leaf]);
37    println!("next seed {next_seed:#018x}");
38}

Source

pub const fn parent(&self) -> u32

The lineage link.

Source

pub const fn root_sentinel_byte(&self) -> u8

The raw root sentinel byte at payload index 243.

Source

pub const fn root_sentinel(&self) -> Option<Sentinel>

The active phase, or None if the root byte is a coordinate.

Source

pub const fn leaves(&self) -> &[u8; 243]

The 243 raw leaf bytes: deltas 0..243 or in-band sentinels.

Source

pub const fn trie_index(path: [u8; 5]) -> usize

Leaf index 0..243 of a 5-tier ternary path. Every tier must be in 0..3; anything else is a panic, because the path is the address.

Examples found in repository ?

examples/quick_start.rs (line 14)

5fn main() {
6    // 1. A 256-byte word with a seed, a parent link, and in-band sentinels.
7    let mut raw = Word256 {
8        hash: 0xcbf2_9ce4_8422_2325,
9        parent: 0,
10        trits: [0u8; 244],
11    };
12
13    // Address leaf [1, 0, 2, 1, 2] in the 5-tier ternary trie (each tier in 0..3).
14    let target_leaf = PertaroExpert243::trie_index([1, 0, 2, 1, 2]);
15    raw.trits[target_leaf] = 42; // residual override: +42 mod 243
16
17    // Stamp a defeated branch with an in-band Tombstone (245).
18    let defeated_leaf = PertaroExpert243::trie_index([2, 2, 0, 1, 0]);
19    raw.trits[defeated_leaf] = Sentinel::Tombstone as u8;
20
21    // Mark the root horizon sentinel at trits[243].
22    raw.trits[ROOT_SENTINEL] = Sentinel::NullNode as u8;
23
24    // 2. Wrap in the zero-cost view and materialize.
25    let expert = PertaroExpert243(raw);
26    let materialized: Word256 = expert.materialize();
27
28    assert!(materialized.trits[target_leaf] < MAX_PACKED);
29    assert_eq!(materialized.trits[defeated_leaf], Sentinel::Tombstone as u8);
30    assert_eq!(materialized.hash, expert.seed());
31
32    // 3. Reground the winning Tier-5 leaf (0..243) into a fresh seed.
33    let next_seed = expert.reground_seed(target_leaf as u8, Sentinel::BusIndirect);
34    assert_ne!(next_seed, expert.seed());
35
36    println!("leaf {target_leaf} -> {}", materialized.trits[target_leaf]);
37    println!("next seed {next_seed:#018x}");
38}

Source

pub const fn default_field(seed: u64, out: &mut [u8; 243])

Fill out with 243 uniform Z_243 digits from the seed’s xorshift64 stream by radix-243 extraction with word rejection. A zero seed is replaced by FNV1A64_BASIS so the stream is never the zero fixed point.

Source

pub const fn materialize(&self) -> Word256

Materialize the expert: header and root byte copied verbatim, each leaf resolved as (base + delta) mod 243, or by its in-band sentinel (NullNode keeps the base; every other sentinel propagates as-is).

Examples found in repository ?

examples/quick_start.rs (line 26)

5fn main() {
6    // 1. A 256-byte word with a seed, a parent link, and in-band sentinels.
7    let mut raw = Word256 {
8        hash: 0xcbf2_9ce4_8422_2325,
9        parent: 0,
10        trits: [0u8; 244],
11    };
12
13    // Address leaf [1, 0, 2, 1, 2] in the 5-tier ternary trie (each tier in 0..3).
14    let target_leaf = PertaroExpert243::trie_index([1, 0, 2, 1, 2]);
15    raw.trits[target_leaf] = 42; // residual override: +42 mod 243
16
17    // Stamp a defeated branch with an in-band Tombstone (245).
18    let defeated_leaf = PertaroExpert243::trie_index([2, 2, 0, 1, 0]);
19    raw.trits[defeated_leaf] = Sentinel::Tombstone as u8;
20
21    // Mark the root horizon sentinel at trits[243].
22    raw.trits[ROOT_SENTINEL] = Sentinel::NullNode as u8;
23
24    // 2. Wrap in the zero-cost view and materialize.
25    let expert = PertaroExpert243(raw);
26    let materialized: Word256 = expert.materialize();
27
28    assert!(materialized.trits[target_leaf] < MAX_PACKED);
29    assert_eq!(materialized.trits[defeated_leaf], Sentinel::Tombstone as u8);
30    assert_eq!(materialized.hash, expert.seed());
31
32    // 3. Reground the winning Tier-5 leaf (0..243) into a fresh seed.
33    let next_seed = expert.reground_seed(target_leaf as u8, Sentinel::BusIndirect);
34    assert_ne!(next_seed, expert.seed());
35
36    println!("leaf {target_leaf} -> {}", materialized.trits[target_leaf]);
37    println!("next seed {next_seed:#018x}");
38}

Source

pub const fn reground_seed(&self, winner: u8, next: Sentinel) -> u64

Reground at the Tier-5 boundary: fold the seed, the winning leaf (0..243) and the next phase through FNV-1a, then one xorshift64 step. A winner at or above 243 is a panic: sentinels are not leaves.

Examples found in repository ?

examples/quick_start.rs (line 33)

5fn main() {
6    // 1. A 256-byte word with a seed, a parent link, and in-band sentinels.
7    let mut raw = Word256 {
8        hash: 0xcbf2_9ce4_8422_2325,
9        parent: 0,
10        trits: [0u8; 244],
11    };
12
13    // Address leaf [1, 0, 2, 1, 2] in the 5-tier ternary trie (each tier in 0..3).
14    let target_leaf = PertaroExpert243::trie_index([1, 0, 2, 1, 2]);
15    raw.trits[target_leaf] = 42; // residual override: +42 mod 243
16
17    // Stamp a defeated branch with an in-band Tombstone (245).
18    let defeated_leaf = PertaroExpert243::trie_index([2, 2, 0, 1, 0]);
19    raw.trits[defeated_leaf] = Sentinel::Tombstone as u8;
20
21    // Mark the root horizon sentinel at trits[243].
22    raw.trits[ROOT_SENTINEL] = Sentinel::NullNode as u8;
23
24    // 2. Wrap in the zero-cost view and materialize.
25    let expert = PertaroExpert243(raw);
26    let materialized: Word256 = expert.materialize();
27
28    assert!(materialized.trits[target_leaf] < MAX_PACKED);
29    assert_eq!(materialized.trits[defeated_leaf], Sentinel::Tombstone as u8);
30    assert_eq!(materialized.hash, expert.seed());
31
32    // 3. Reground the winning Tier-5 leaf (0..243) into a fresh seed.
33    let next_seed = expert.reground_seed(target_leaf as u8, Sentinel::BusIndirect);
34    assert_ne!(next_seed, expert.seed());
35
36    println!("leaf {target_leaf} -> {}", materialized.trits[target_leaf]);
37    println!("next seed {next_seed:#018x}");
38}