Struct BeamSearchDecoder 

pub struct BeamSearchDecoder {
    pub config: BeamSearchConfig,
}

Beam search decoder.

Fields

config: BeamSearchConfig

Configuration controlling all search behaviour.

Implementations

impl BeamSearchDecoder

pub fn new(config: BeamSearchConfig) -> Self

Create a decoder with the supplied configuration.

pub fn with_default() -> Self

Create a decoder with default configuration.

pub fn initial_state(&self, bos_token_id: usize) -> BeamState

Create an initial BeamState seeded with bos_token_id.

pub fn step( &self, state: BeamState, input: &BeamStepInput, ) -> Result<BeamState, BeamSearchError>

Perform one step of beam search.

Given the current state and per-beam log-probabilities input, advance each beam by one token, prune to the top-beam_width candidates, and handle EOS/completion logic.

pub fn decode<F>( &self, bos_token_id: usize, score_fn: F, ) -> Result<BeamSearchResult, BeamSearchError>

where F: Fn(&[&[usize]]) -> Result<Vec<Vec<f64>>, String>,

Run a full beam search.

score_fn is called at each step with the current beam sequences and must return log-probabilities of shape [num_active_beams][vocab_size].

pub fn top_k_results(&self, state: &BeamState, k: usize) -> Vec<BeamHypothesis>

Extract the top-k hypotheses from a beam state, sorted by score descending.

pub fn apply_temperature(logits: &[f64], temperature: f64) -> Vec<f64>

Apply temperature scaling to logits: logits[i] / temperature.

pub fn log_softmax(logits: &[f64]) -> Vec<f64>

Compute numerically stable log-softmax.

Uses the log-sum-exp trick: lse = max + log(sum(exp(x - max))), log_softmax(x_i) = x_i - lse.

pub fn top_k_filter_logits(logits: &mut [f64], k: usize)

Zero out all but the top-k logits in place (set others to NEG_INFINITY).