56 lines
1.6 KiB
Rust
56 lines
1.6 KiB
Rust
use nalgebra::*;
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use rand_distr::StandardNormal;
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extern crate rand as r;
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enum ActivationFunc {
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Sigmoid,
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Tanh,
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ReLU,
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}
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pub struct NN {
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config: Vec<usize>,
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weights: Vec<DMatrix<f32>>,
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activ_func: ActivationFunc,
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}
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impl NN {
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// Vec of number of neurons in input, hidden 1, hidden 2, ..., output layers
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pub fn new(config: Vec<usize>) -> Self {
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let mut rng = r::thread_rng();
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Self {
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config: config
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.iter()
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.enumerate()
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.map(|(i, &x)| if i != config.len() - 1 { x + 1 } else { x })
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.collect(),
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// He-et-al Initialization
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weights: config
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.iter()
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.zip(config.iter().skip(1))
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.map(|(&curr, &last)| {
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DMatrix::<f32>::from_distribution(last, curr + 1, &StandardNormal, &mut rng)
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* (2. / last as f32).sqrt()
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})
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.collect(),
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activ_func: ActivationFunc::ReLU,
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}
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}
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pub fn feed_forward(&self, inputs: Vec<f32>) -> Vec<f32> {
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let mut y = DMatrix::from_vec(inputs.len(), 1, inputs);
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for i in 0..self.config.len() - 1 {
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y = (&self.weights[i] * y.insert_row(self.config[i] - 1, 1.)).map(|x| {
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match self.activ_func {
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ActivationFunc::ReLU => x.max(0.),
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ActivationFunc::Sigmoid => 1. / (1. + (-x).exp()),
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ActivationFunc::Tanh => x.tanh(),
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}
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});
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}
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y.column(0).data.into_slice().to_vec()
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}
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}
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