Struct DiverseBeam 

pub struct DiverseBeam {
    pub cfg: DiverseBeamConfig,
}

Diverse beam search decoder.

Fields

cfg: DiverseBeamConfig

Implementations

impl DiverseBeam

pub fn new(cfg: DiverseBeamConfig) -> SeqResult<Self>

Validate configuration and create a new DiverseBeam.

pub fn search<F>(&self, score_fn: F) -> SeqResult<Vec<Vec<usize>>>

where F: Fn(&[usize]) -> Vec<f32>,

Run diverse beam search.

Groups decode sequentially at each time step. Group g receives a Hamming diversity penalty based on the tokens that groups 0..g-1 committed to at the current step.

Returns beam_width sequences (all groups concatenated), each a vector of token IDs.

pub fn hamming_penalty( token: usize, prev_group_tokens: &[usize], strength: f32, ) -> f32

Hamming diversity penalty for token.

Counts how many elements of prev_group_tokens equal token, then multiplies by strength. This penalises tokens already chosen by earlier groups at the current decoding step.

pub fn length_norm(score: f32, len: usize, alpha: f32) -> f32

GNMT-style length normalisation: score / ((5 + len) / 6)^alpha.

When alpha == 0.0 the denominator is 1.0 (no normalisation).

pub fn top_k(log_probs: &[f32], k: usize) -> Vec<(usize, f32)>

Return the top-k (token, score) pairs sorted by score descending.

Trait Implementations

impl Clone for DiverseBeam

fn clone(&self) -> DiverseBeam

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for DiverseBeam

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.