Enum CfcMode 

pub enum CfcMode {
    Default = 0,
    Pure = 1,
    NoGate = 2,
}

Operating modes for CfC cells.

Each mode implements a different approach to computing the hidden state update. The choice affects both computational cost and model behavior.

Mode Comparison

Mode	Formula	Best For
Default	h = tanh(ff1) × (1-σ) + tanh(ff2) × σ	Most tasks (recommended)
Pure	h = a - a × exp(-t × |w_τ| + |ff1|) × ff1	Biological accuracy
NoGate	h = tanh(ff1) + tanh(ff2) × σ	Simple dynamics

Choosing a Mode

Default (Recommended)

The gated interpolation mode provides the best balance of:

• Expressive power (two separate paths)
• Training stability (sigmoid gating)
• Flexibility (learns when to use each path)

Use this unless you have a specific reason not to.

Pure

The ODE-based mode is closer to the original LTC formulation:

• More biologically plausible
• Direct continuous-time dynamics
• Can be less stable during training
• Fewer parameters (no ff2, time_a, time_b)

Use when biological accuracy matters or for comparison studies.

NoGate

The additive mode simplifies the gating mechanism:

• Adds instead of interpolates
• Can be easier to train on simple tasks
• May underfit on complex tasks

Use for simple sequential patterns or ablation studies.

Variants

Default = 0

Recommended. Gated interpolation between two feedforward paths.

Formula: h = tanh(ff1) × (1 - σ(t)) + tanh(ff2) × σ(t)

The time-dependent sigmoid σ(t) = sigmoid(time_a × t + time_b) controls how much each path contributes to the output.

Pure = 1

Pure ODE solution without gating. More biologically plausible.

Formula: h = a - a × exp(-t × (|w_τ| + |ff1|)) × ff1

Uses learned time constants w_τ and amplitude a. Has fewer parameters than Default mode.

NoGate = 2

Simplified additive mode (no interpolation).

Formula: h = tanh(ff1) + tanh(ff2) × σ(t)

Adds the gated component instead of interpolating. Can work well for simpler tasks.

Trait Implementations

impl Clone for CfcMode

fn clone(&self) -> CfcMode

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for CfcMode

impl Debug for CfcMode

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for CfcMode

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for CfcMode

impl PartialEq for CfcMode

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for CfcMode

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for CfcMode