FlexNN::Activations Namespace Reference

Namespaces
namespace	detail

Classes
struct	ActivationParameters
	Hyperparameters for activations. More...

Enumerations
enum class	Activation : uint8_t {   None = 0 , ReLU = 1 , LeakyReLU = 2 , Sigmoid = 3 ,   Tanh = 4 , Softmax = 5 }
	Activation function identifier. More...

Functions
const char *	to_string (Activation a) noexcept
	Convert Activation to canonical lower-case string.
bool	try_parse (std::string_view s, Activation &out) noexcept
	Parse a string into an Activation.

Variables
constexpr double	kDefaultLeakyAlpha = 0.01
	Default slope for LeakyReLU negative side (matches LLD_FLEXNN §4, v0.1).

Enumeration Type Documentation

Activation

enum class FlexNN::Activations::Activation : uint8_t

strong

Activation function identifier.

Values are stable on-wire (model.bin) — do not reorder. 0 is linear (pre-BatchNorm or debugging). LeakyReLU alpha is configurable per-layer via ActivationParameters (default 0.01, see ActivationParameters.hpp); model.bin v2 stores it as 1 float32 in aux when act==LeakyReLU.

Enumerator
None	Linear, no activation.
ReLU	max(0, z)
LeakyReLU	z>0 ? z : alpha*z (alpha from ActivationParameters)
Sigmoid	1/(1+exp(-z)), clamped
Tanh	std::tanh(z)
Softmax	Stable col-wise softmax — only on last layer in v0.1.

Function Documentation

to_string()

const char * FlexNN::Activations::to_string ( Activation  a )

noexcept

Convert Activation to canonical lower-case string.

Parameters

a	Activation value

Returns

Non-owning C-string (e.g., "relu", "leaky_relu"). Returns "none" for unknown values (should be unreachable — all 6 values are covered).

try_parse()

bool FlexNN::Activations::try_parse ( std::string_view  s, Activation &  out  )

noexcept

Parse a string into an Activation.

Case-insensitive, trims ASCII whitespace. Accepts canonical names ("relu", "leaky_relu", "leakyrelu", "sigmoid", "tanh", "softmax", "none") and common aliases ("leaky-relu", "lrelu", "linear" for None). Returns false on unknown input without throwing — caller decides whether to treat as None or error.

Note

noexcept: heap allocation for lowercasing may throw bad_alloc and terminate via std::terminate (acceptable for host training; tests use small strings).

Parameters

s	Input view (not null-terminated required)
out	Output activation on success

Returns

true if parsed, false otherwise (out unchanged on false)

Variable Documentation

kDefaultLeakyAlpha

constexpr double FlexNN::Activations::kDefaultLeakyAlpha = 0.01

inlineconstexpr

Default slope for LeakyReLU negative side (matches LLD_FLEXNN §4, v0.1).