Add support for Llama 3.1 (#2359)

* Add Llama 3.1 rope

* Clippy

* Format

* Clippy

* Add support for multiple eos tokens:

* Untagged either

* Remove either dep and fix settings.json

* Make the max positional embeddings configurable
This commit is contained in:
Eric Buehler
2024-07-26 15:32:26 -04:00
committed by GitHub
parent ddafc61055
commit 0f5cbb08b3
24 changed files with 165 additions and 71 deletions

View File

@ -1,9 +1,33 @@
use super::with_tracing::{linear_no_bias as linear, Linear, RmsNorm};
use candle::{DType, Device, IndexOp, Result, Tensor, D};
use candle_nn::{embedding, Embedding, Module, VarBuilder};
use std::collections::HashMap;
use std::{collections::HashMap, f32::consts::PI};
pub const MAX_SEQ_LEN: usize = 4096;
pub const DEFAULT_MAX_SEQ_LEN: usize = 4096;
#[derive(Debug, Clone, serde::Deserialize, Default)]
pub enum Llama3RopeType {
#[serde(rename = "llama3")]
Llama3,
#[default]
#[serde(rename = "default")]
Default,
}
#[derive(Debug, Clone, serde::Deserialize, Default)]
pub struct Llama3RopeConfig {
pub factor: f32,
pub low_freq_factor: f32,
pub high_freq_factor: f32,
pub original_max_position_embeddings: usize,
pub rope_type: Llama3RopeType,
}
#[derive(Debug, Clone, serde::Deserialize)]
#[serde(untagged)]
pub enum LlamaEosToks {
Single(u32),
Multiple(Vec<u32>),
}
#[derive(Debug, Clone, serde::Deserialize)]
pub struct LlamaConfig {
@ -17,7 +41,9 @@ pub struct LlamaConfig {
#[serde(default = "default_rope")]
pub rope_theta: f32,
pub bos_token_id: Option<u32>,
pub eos_token_id: Option<u32>,
pub eos_token_id: Option<LlamaEosToks>,
pub rope_scaling: Option<Llama3RopeConfig>,
pub max_position_embeddings: usize,
}
impl LlamaConfig {
@ -44,6 +70,8 @@ impl LlamaConfig {
use_flash_attn,
bos_token_id: self.bos_token_id,
eos_token_id: self.eos_token_id,
rope_scaling: self.rope_scaling,
max_position_embeddings: self.max_position_embeddings,
}
}
}
@ -60,7 +88,9 @@ pub struct Config {
pub rms_norm_eps: f64,
pub rope_theta: f32,
pub bos_token_id: Option<u32>,
pub eos_token_id: Option<u32>,
pub eos_token_id: Option<LlamaEosToks>,
pub rope_scaling: Option<Llama3RopeConfig>,
pub max_position_embeddings: usize,
}
impl Config {
@ -77,6 +107,8 @@ impl Config {
rope_theta: 10_000.0,
bos_token_id: None,
eos_token_id: None,
rope_scaling: None,
max_position_embeddings: DEFAULT_MAX_SEQ_LEN,
}
}
@ -93,6 +125,8 @@ impl Config {
rope_theta: 10_000.0,
bos_token_id: None,
eos_token_id: None,
rope_scaling: None,
max_position_embeddings: DEFAULT_MAX_SEQ_LEN,
}
}
}
@ -107,18 +141,54 @@ pub struct Cache {
device: Device,
}
fn calculate_default_inv_freq(cfg: &Config) -> Vec<f32> {
let head_dim = cfg.hidden_size / cfg.num_attention_heads;
(0..head_dim)
.step_by(2)
.map(|i| 1f32 / cfg.rope_theta.powf(i as f32 / head_dim as f32))
.collect()
}
impl Cache {
pub fn new(use_kv_cache: bool, dtype: DType, config: &Config, device: &Device) -> Result<Self> {
// precompute freqs_cis
let n_elem = config.hidden_size / config.num_attention_heads;
let theta: Vec<_> = (0..n_elem)
.step_by(2)
.map(|i| 1f32 / config.rope_theta.powf(i as f32 / n_elem as f32))
.collect();
let theta = Tensor::new(theta.as_slice(), device)?;
let idx_theta = Tensor::arange(0, MAX_SEQ_LEN as u32, device)?
let theta = match &config.rope_scaling {
None
| Some(Llama3RopeConfig {
rope_type: Llama3RopeType::Default,
..
}) => calculate_default_inv_freq(config),
Some(rope_scaling) => {
let low_freq_wavelen = rope_scaling.original_max_position_embeddings as f32
/ rope_scaling.low_freq_factor;
let high_freq_wavelen = rope_scaling.original_max_position_embeddings as f32
/ rope_scaling.high_freq_factor;
calculate_default_inv_freq(config)
.into_iter()
.map(|freq| {
let wavelen = 2. * PI / freq;
if wavelen < high_freq_wavelen {
freq
} else if wavelen > low_freq_wavelen {
freq / rope_scaling.factor
} else {
let smooth = (rope_scaling.original_max_position_embeddings as f32
/ wavelen
- rope_scaling.low_freq_factor)
/ (rope_scaling.high_freq_factor - rope_scaling.low_freq_factor);
(1. - smooth) * freq / rope_scaling.factor + smooth * freq
}
})
.collect::<Vec<_>>()
}
};
let theta = Tensor::new(theta, device)?;
let idx_theta = Tensor::arange(0, config.max_position_embeddings as u32, device)?
.to_dtype(DType::F32)?
.reshape((MAX_SEQ_LEN, 1))?
.reshape((config.max_position_embeddings, 1))?
.matmul(&theta.reshape((1, theta.elem_count()))?)?;
// This is different from the paper, see:
// https://github.com/huggingface/transformers/blob/6112b1c6442aaf7affd2b0676a1cd4eee30c45cf/src/transformers/models/llama/modeling_llama.py#L112
@ -160,6 +230,7 @@ struct CausalSelfAttention {
use_flash_attn: bool,
span: tracing::Span,
span_rot: tracing::Span,
max_position_embeddings: usize,
}
#[cfg(feature = "flash-attn")]
@ -220,15 +291,23 @@ impl CausalSelfAttention {
k = Tensor::cat(&[cache_k, &k], 2)?.contiguous()?;
v = Tensor::cat(&[cache_v, &v], 2)?.contiguous()?;
let k_seq_len = k.dims()[1];
if k_seq_len > MAX_SEQ_LEN {
if k_seq_len > self.max_position_embeddings {
k = k
.narrow(D::Minus1, k_seq_len - MAX_SEQ_LEN, MAX_SEQ_LEN)?
.narrow(
D::Minus1,
k_seq_len - self.max_position_embeddings,
self.max_position_embeddings,
)?
.contiguous()?
}
let v_seq_len = v.dims()[1];
if v_seq_len > 2 * MAX_SEQ_LEN {
if v_seq_len > 2 * self.max_position_embeddings {
v = v
.narrow(D::Minus1, v_seq_len - MAX_SEQ_LEN, MAX_SEQ_LEN)?
.narrow(
D::Minus1,
v_seq_len - self.max_position_embeddings,
self.max_position_embeddings,
)?
.contiguous()?
}
}
@ -291,6 +370,7 @@ impl CausalSelfAttention {
use_flash_attn: cfg.use_flash_attn,
span,
span_rot,
max_position_embeddings: cfg.max_position_embeddings,
})
}
}