Struct Lookahead 

pub struct Lookahead<O> { /* private fields */ }

Lookahead optimizer wrapper.

Maintains “slow weights” that are periodically interpolated toward the fast weights produced by the inner optimizer. Every k calls to step, the slow weights are updated via:

slow_w = slow_w + alpha * (fast_w - slow_w)
fast_w = slow_w

Implementations

impl<O: StepOptimizer> Lookahead<O>

pub fn new(inner: O, alpha: f32, k: usize) -> Self

Creates a new Lookahead wrapper around the given optimizer.

• alpha — interpolation coefficient (typically 0.5).
• k — synchronisation period (typically 5).

pub fn step( &mut self, parameter_id: u64, weights: &mut Tensor, grad: &Tensor, ) -> Result<(), OptimError>

Performs one optimisation step.

1. Delegates to the inner optimizer to update the fast weights.
2. Increments the internal step counter.
3. Every k steps, synchronises slow and fast weights.

Trait Implementations

impl<O: Clone> Clone for Lookahead<O>

fn clone(&self) -> Lookahead<O>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<O: Debug> Debug for Lookahead<O>

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

Formats the value using the given formatter.