Struct PoissonEncoder 

pub struct PoissonEncoder {
    pub num_steps: usize,
}

Poisson spike train encoder.

Generates spike trains with Poisson-distributed timing based on either a per-step probability or an explicit firing rate and time step.

Mathematical Model

// Dimensionless probability input:
probability = clamp(input, 0.0, 1.0)
spike[i] = 1 if random() < probability else 0

// Physical rate input:
probability = 1 - exp(-rate_hz * dt_seconds)  // via -exp_m1(-x) in f32

When to Use

• Generating baseline spike trains with controllable average rates
• Poisson-like random spike generation for stochastic encoders
• Creating temporal patterns with controllable firing rates

Note

This encoder is NOT part of the Encoder trait because its output type (Vec<u8>) differs from other encoders (EncodedOutput). It operates in a different mode: the input is a single probability (0.0 to 1.0) and the output is a spike train over multiple time steps.

Examples

use axon_encoder::prelude::*;

let enc = PoissonEncoder::new(32);
let train = enc.encode(0.0); // never spikes
assert_eq!(train.len(), 32);
assert!(train.iter().all(|&b| b == 0));

let p = probability_from_rate_hz(50.0, 0.001);
assert!((0.0..=1.0).contains(&p));

Fields

num_steps: usize

Implementations

impl PoissonEncoder

pub fn new(steps: usize) -> Self

pub fn encode_rate_hz(&self, rate_hz: f32, dt_seconds: f32) -> Vec<u8>

Encodes a firing rate in hertz into a spike train using an explicit time step in seconds for each bin.

pub fn encode_rate_hz_step(&self, rate_hz: f32, dt_seconds: f32) -> u8

Encodes a single rate-based step using an explicit time step in seconds.

pub fn encode(&self, input: f32) -> Vec<u8>

Encodes a single probability value into a spike train.

Each of the num_steps represents an independent time step where a spike occurs with the given probability.

pub fn encode_step(&self, input: f32) -> u8

Encodes a single step - returns 1 or 0 based on input probability.

Useful for streaming mode where you want one spike decision at a time.

Trait Implementations

impl Clone for PoissonEncoder

fn clone(&self) -> PoissonEncoder

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PoissonEncoder

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

Formats the value using the given formatter.