Files
candle/candle-nn/src/linear.rs
Laurent Mazare 7396b8ed1a Segment Anything - process images (#766)
* Start processing images.

* Add LayerNorm2d.

* Properly use LayerNorm2d.

* Tweak eps.

* Use LayerNorm on inputs with a rank different from 3.

* Window partitioning.

* Fix a couple todos.

* More todos.

* Hard-code the einsums.

* More padding support.

* Some sizes tweaks.

* Use the hub to get the weights.

* Use a batch matmul.

* Tweaks.

* More fixes.

* Get some predictions to be generated.
2023-09-07 19:22:45 +01:00

77 lines
2.4 KiB
Rust

//! Linear layer
//!
//! This layer applies a linear transformation to the incoming data, `y = x@w.t() + b`.
//! The bias is optional. The `forward` method can be used to apply the layer, it supports input
//! with a batch dimension (so of shape `(b_sz, in_c)`) or without (of shape `(in_c,)`), the
//! output has shape `(b_sz, out_c)` and `(out_c,)` respectively.
//!
//! ```rust
//! use candle::{Tensor, Device::Cpu};
//! use candle_nn::{Linear, Module};
//! # fn main() -> candle::Result<()> {
//!
//! let w = Tensor::new(&[[1f32, 2.], [3., 4.], [5., 6.]], &Cpu)?;
//! let layer = Linear::new(w, None); // Use no bias.
//! let xs = Tensor::new(&[[10f32, 100.]], &Cpu)?;
//! let ys = layer.forward(&xs)?;
//! assert_eq!(ys.to_vec2::<f32>()?, &[[210.0, 430.0, 650.0]]);
//! # Ok(()) }
//! ```
use candle::{Result, Tensor};
#[derive(Debug)]
pub struct Linear {
weight: Tensor,
bias: Option<Tensor>,
}
impl Linear {
pub fn new(weight: Tensor, bias: Option<Tensor>) -> Self {
Self { weight, bias }
}
pub fn weight(&self) -> &Tensor {
&self.weight
}
pub fn bias(&self) -> Option<&Tensor> {
self.bias.as_ref()
}
}
impl super::Module for Linear {
fn forward(&self, x: &Tensor) -> candle::Result<Tensor> {
let w = match *x.dims() {
[b1, b2, _, _] => self.weight.broadcast_left((b1, b2))?.t()?,
[bsize, _, _] => self.weight.broadcast_left(bsize)?.t()?,
_ => self.weight.t()?,
};
let x = x.matmul(&w)?;
match &self.bias {
None => Ok(x),
Some(bias) => x.broadcast_add(bias),
}
}
}
/// Create or initialize a new linear layer.
///
/// This uses some default names for weight and biases, namely `"weight"` and `"bias"`.
pub fn linear(in_dim: usize, out_dim: usize, vs: crate::VarBuilder) -> Result<Linear> {
let init_ws = crate::init::DEFAULT_KAIMING_NORMAL;
let ws = vs.get_with_hints((out_dim, in_dim), "weight", init_ws)?;
let bound = 1. / (in_dim as f64).sqrt();
let init_bs = crate::Init::Uniform {
lo: -bound,
up: bound,
};
let bs = vs.get_with_hints(out_dim, "bias", init_bs)?;
Ok(Linear::new(ws, Some(bs)))
}
pub fn linear_no_bias(in_dim: usize, out_dim: usize, vs: crate::VarBuilder) -> Result<Linear> {
let init_ws = crate::init::DEFAULT_KAIMING_NORMAL;
let ws = vs.get_with_hints((out_dim, in_dim), "weight", init_ws)?;
Ok(Linear::new(ws, None))
}