use crate::layers::layer::Layer;
use crate::tensor::Tensor;
use crate::layers::layer::LearnableParams;
pub struct Sigmoid {
input: Tensor
}
impl Layer for Sigmoid {
fn get_info(&self) -> String {
format!("Sigmoid Layer")
}
fn forward(&mut self, input: Tensor, _training: bool) -> Tensor {
self.input = input;
self.input.map(|x| Sigmoid::sigmoid(x))
}
fn backward(&mut self, gradient: &Tensor) -> Tensor {
let tanh_grad = self.input.map(|x| Sigmoid::sigmoid_prime(x));
gradient.mult_el(&tanh_grad)
}
fn get_params_list(&self) -> Vec<LearnableParams> {
vec![]
}
fn get_grad(&self, _param: &LearnableParams) -> &Tensor {
panic!("Layer does not have learnable parameters.")
}
fn get_param(&mut self, _param: &LearnableParams) -> &mut Tensor {
panic!("Layer does not have learnable parameters.")
}
}
impl Sigmoid {
pub fn sigmoid(x: f64) -> f64 {
1. / (1. + (-x).exp())
}
pub fn sigmoid_prime(x: f64) -> f64 {
Self::sigmoid(x) * (1. - Self::sigmoid(x))
}
pub fn new() -> Sigmoid {
Sigmoid {
input: Tensor::new(vec![], vec![])
}
}
}