More general seq forward functions for RNNs. (#1050)

This commit is contained in:
Laurent Mazare
2023-10-07 15:08:01 +01:00
committed by GitHub
parent aa53368aeb
commit a4967600d0

View File

@ -4,7 +4,7 @@ use candle::{DType, Device, IndexOp, Result, Tensor};
/// Trait for Recurrent Neural Networks.
#[allow(clippy::upper_case_acronyms)]
pub trait RNN {
type State;
type State: Clone;
/// A zero state from which the recurrent network is usually initialized.
fn zero_state(&self, batch_dim: usize) -> Result<Self::State>;
@ -18,7 +18,7 @@ pub trait RNN {
///
/// The input should have dimensions [batch_size, seq_len, features].
/// The initial state is the result of applying zero_state.
fn seq(&self, input: &Tensor) -> Result<(Tensor, Self::State)> {
fn seq(&self, input: &Tensor) -> Result<Vec<Self::State>> {
let batch_dim = input.dim(0)?;
let state = self.zero_state(batch_dim)?;
self.seq_init(input, &state)
@ -27,7 +27,23 @@ pub trait RNN {
/// Applies multiple steps of the recurrent network.
///
/// The input should have dimensions [batch_size, seq_len, features].
fn seq_init(&self, input: &Tensor, state: &Self::State) -> Result<(Tensor, Self::State)>;
fn seq_init(&self, input: &Tensor, init_state: &Self::State) -> Result<Vec<Self::State>> {
let (_b_size, seq_len, _features) = input.dims3()?;
let mut output = Vec::with_capacity(seq_len);
for seq_index in 0..seq_len {
let input = input.i((.., seq_index, ..))?;
let state = if seq_index == 0 {
self.step(&input, init_state)?
} else {
self.step(&input, &output[seq_index - 1])?
};
output.push(state);
}
Ok(output)
}
/// Converts a sequence of state to a tensor.
fn states_to_tensor(&self, states: &[Self::State]) -> Result<Tensor>;
}
/// The state for a LSTM network, this contains two tensors.
@ -179,18 +195,9 @@ impl RNN for LSTM {
})
}
/// The input should have dimensions [batch_size, seq_len, features].
fn seq_init(&self, input: &Tensor, in_state: &Self::State) -> Result<(Tensor, Self::State)> {
let (_b_size, seq_len, _features) = input.dims3()?;
let mut state = in_state.clone();
let mut output: Vec<Tensor> = Vec::with_capacity(seq_len);
for seq_index in 0..seq_len {
let input = input.i((.., seq_index, ..))?;
state = self.step(&input, &state)?;
output.push(state.h.clone());
}
let output = Tensor::cat(&output, 1)?;
Ok((output, state))
fn states_to_tensor(&self, states: &[Self::State]) -> Result<Tensor> {
let states = states.iter().map(|s| s.h.clone()).collect::<Vec<_>>();
Tensor::cat(&states, 1)
}
}
@ -322,17 +329,8 @@ impl RNN for GRU {
Ok(GRUState { h: next_h })
}
/// The input should have dimensions [batch_size, seq_len, features].
fn seq_init(&self, input: &Tensor, in_state: &Self::State) -> Result<(Tensor, Self::State)> {
let (_b_size, seq_len, _features) = input.dims3()?;
let mut state = in_state.clone();
let mut output: Vec<Tensor> = Vec::with_capacity(seq_len);
for seq_index in 0..seq_len {
let input = input.i((.., seq_index, ..))?;
state = self.step(&input, &state)?;
output.push(state.h.clone());
}
let output = Tensor::cat(&output, 1)?;
Ok((output, state))
fn states_to_tensor(&self, states: &[Self::State]) -> Result<Tensor> {
let states = states.iter().map(|s| s.h.clone()).collect::<Vec<_>>();
Tensor::cat(&states, 1)
}
}