mirror of
https://github.com/huggingface/candle.git
synced 2025-06-19 19:58:35 +00:00
ff876c2103
* Rework the var-builder to handle initializations. * Add some helper functions for layer creation. * Improve the layer initializations. * Get initialized variables. * Precompute the rot embeddings when training lamas.
66 lines
2.2 KiB
Rust
66 lines
2.2 KiB
Rust
//! Linear layer
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//!
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//! This layer applies a linear transformation to the incoming data, `y = x@w.t() + b`.
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//! The bias is optional. The `forward` method can be used to apply the layer, it supports input
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//! with a batch dimension (so of shape `(b_sz, in_c)`) or without (of shape `(in_c,)`), the
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//! output has shape `(b_sz, out_c)` and `(out_c,)` respectively.
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//!
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//! ```rust
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//! use candle::{Tensor, Device::Cpu};
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//! use candle_nn::Linear;
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//! # fn main() -> candle::Result<()> {
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//!
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//! let w = Tensor::new(&[[1f32, 2.], [3., 4.], [5., 6.]], &Cpu)?;
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//! let layer = Linear::new(w, None); // Use no bias.
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//! let xs = Tensor::new(&[[10f32, 100.]], &Cpu)?;
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//! let ys = layer.forward(&xs)?;
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//! assert_eq!(ys.to_vec2::<f32>()?, &[[210.0, 430.0, 650.0]]);
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//! # Ok(()) }
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//! ```
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use candle::{Result, Tensor};
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#[derive(Debug)]
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pub struct Linear {
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weight: Tensor,
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bias: Option<Tensor>,
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}
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impl Linear {
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pub fn new(weight: Tensor, bias: Option<Tensor>) -> Self {
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Self { weight, bias }
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}
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pub fn forward(&self, x: &Tensor) -> candle::Result<Tensor> {
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let w = match x.dims() {
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&[bsize, _, _] => self.weight.broadcast_left(bsize)?.t()?,
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_ => self.weight.t()?,
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};
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let x = x.matmul(&w)?;
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match &self.bias {
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None => Ok(x),
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Some(bias) => x.broadcast_add(bias),
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}
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}
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}
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/// Create or initialize a new linear layer.
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///
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/// This uses some default names for weight and biases, namely `"weight"` and `"bias"`.
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pub fn linear(in_dim: usize, out_dim: usize, vs: crate::VarBuilder) -> Result<Linear> {
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let init_ws = crate::init::DEFAULT_KAIMING_NORMAL;
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let ws = vs.get_or_init((out_dim, in_dim), "weight", init_ws)?;
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let bound = 1. / (in_dim as f64).sqrt();
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let init_bs = crate::Init::Uniform {
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lo: -bound,
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up: bound,
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};
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let bs = vs.get_or_init(out_dim, "bias", init_bs)?;
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Ok(Linear::new(ws, Some(bs)))
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}
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pub fn linear_no_bias(in_dim: usize, out_dim: usize, vs: crate::VarBuilder) -> Result<Linear> {
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let init_ws = crate::init::DEFAULT_KAIMING_NORMAL;
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let ws = vs.get_or_init((out_dim, in_dim), "weight", init_ws)?;
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Ok(Linear::new(ws, None))
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}
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