Sigmoid.hpp File Reference

Sigmoid activation — 1/(1+exp(-Z)) with clamping. More...

#include <algorithm>
#include <Eigen/Dense>
#include <cmath>

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Namespaces
namespace	FlexNN
	Namespace for the FlexNN neural network library.
namespace	FlexNN::Activations
namespace	FlexNN::Activations::detail

Functions
Eigen::MatrixXd	FlexNN::Activations::detail::sigmoid_forward (const Eigen::MatrixXd &Z)
	Sigmoid forward: A = 1/(1+exp(-clamp(Z))) elementwise.
Eigen::MatrixXd	FlexNN::Activations::detail::sigmoid_backward (const Eigen::MatrixXd &dA, const Eigen::MatrixXd &, const Eigen::MatrixXd &A) noexcept
	Sigmoid backward: dZ = dA * A * (1 - A).

Detailed Description

Sigmoid activation — 1/(1+exp(-Z)) with clamping.

Clamping Z to [-15,15] avoids exp overflow and keeps host double stable while the runtime may use a LUT. Matches LLD_FLEXNN §6.5.