Struct Occupancy 

pub struct Occupancy { /* private fields */ }

How the reference’s probability is spread over the frames.

Implementations

impl Occupancy

pub fn num_frames(&self) -> usize

The number of frames.

pub fn num_symbols(&self) -> usize

The number of columns the acoustic model scores.

pub fn frame(&self, frame: usize) -> &[f32]

The posterior of each column in frame, which sums to one.

Panics

If frame is past the last one.

pub fn cost(&self) -> f32

-log P(reference | frames): the cost of the whole chain, over every alignment of it at once.

Always at most Alignment::cost, which is the cost of the single best alignment. The gap measures probability mass carried by alternative alignments.

pub fn label_prior(&self) -> Vec<f32>

How often each column is the right answer, averaged over the frames.

Sums to one. This is the estimate a CTC model trained with label priors wants: the count is taken over the whole alignment posterior rather than over a hard decision, so a frame the model is unsure about contributes to both readings in proportion.

pub fn expected_durations(&self) -> &[f32]

The expected number of frames sounding each position.

The soft counterpart of Alignment::spans, and it answers a question spans cannot: a phone whose span is one frame but whose expected duration is four is a boundary the acoustics did not decide, not a short phone.

pub fn skip_posteriors(&self) -> &[f32]

Per position, how much of the probability took the skip transition into it.

Zero everywhere unless the chain allows skipping. Alignment::skipped reports the best-path decision; this value reports its posterior confidence.

It is an upper bound on the posterior that a phone got no frames at all, and not quite the same thing. Skipping into s_i and then holding phone i is a path the chain allows, and it sounds a phone the skip gave up. It never wins in the tropical semiring, because waiting at s_{i-1} and committing a frame later reaches the same cell having sounded the same phone and costs exactly skip(i) less, so an Alignment never contains one. In the log semiring nothing is discarded, so those paths keep their share, which at a skip cost of several nats is a small one.

Trait Implementations

impl Clone for Occupancy

fn clone(&self) -> Occupancy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Occupancy

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

Formats the value using the given formatter.

impl PartialEq for Occupancy

fn eq(&self, other: &Occupancy) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Occupancy