Use fast rope (#945)

* use fast rope

* fix llama

* use fast rope for llama3.1

* requires unreleased mlx

* fix su

* fix deepseek v2

* only one of base or freqs

* nit

* fix

* hard code freqs
This commit is contained in:
Awni Hannun 2024-08-23 13:18:51 -07:00 committed by GitHub
parent 58591a1b41
commit 6731254e76
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7 changed files with 65 additions and 137 deletions

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@ -68,13 +68,12 @@ def yarn_get_mscale(scale=1, mscale=1):
return 0.1 * mscale * math.log(scale) + 1.0
def yarn_linear_ramp_mask(min, max, dim):
if min == max:
max += 0.001 # Prevent singularity
def yarn_linear_ramp_mask(min_val, max_val, dim):
if min_val == max_val:
max_val += 0.001 # Prevent singularity
linear_func = (mx.arange(dim, dtype=mx.float32) - min) / (max - min)
ramp_func = mx.clip(linear_func, 0, 1)
return ramp_func
linear_func = (mx.arange(dim, dtype=mx.float32) - min_val) / (max_val - min_val)
return mx.clip(linear_func, 0, 1)
class DeepseekV2YarnRotaryEmbedding(nn.Module):
@ -91,72 +90,36 @@ class DeepseekV2YarnRotaryEmbedding(nn.Module):
mscale_all_dim=0,
):
super().__init__()
self.dim = dim
self.max_position_embeddings = max_position_embeddings
self.base = base
self.scaling_factor = scaling_factor
self.original_max_position_embeddings = original_max_position_embeddings
self.beta_fast = beta_fast
self.beta_slow = beta_slow
self.mscale = mscale
self.mscale_all_dim = mscale_all_dim
self.max_seq_len_cached = None
self._cos_cached = None
self._sin_cached = None
self._inv_freq = None
self.set_cos_sin_cache(max_position_embeddings)
def set_cos_sin_cache(self, seq_len):
self.max_seq_len_cached = seq_len
dim = self.dim
freq_extra = 1.0 / (self.base ** (mx.arange(0, dim, 2, dtype=mx.float32) / dim))
freq_inter = 1.0 / (
self.scaling_factor
* self.base ** (mx.arange(0, dim, 2, dtype=mx.float32) / dim)
self.mscale = yarn_get_mscale(scaling_factor, mscale) / yarn_get_mscale(
scaling_factor, mscale_all_dim
)
freq_extra = base ** (mx.arange(0, dim, 2, dtype=mx.float32) / dim)
freq_inter = scaling_factor * base ** (
mx.arange(0, dim, 2, dtype=mx.float32) / dim
)
low, high = yarn_find_correction_range(
self.beta_fast,
self.beta_slow,
beta_fast,
beta_slow,
dim,
self.base,
self.original_max_position_embeddings,
base,
original_max_position_embeddings,
)
inv_freq_mask = 1.0 - yarn_linear_ramp_mask(low, high, dim // 2)
inv_freq = freq_inter * (1 - inv_freq_mask) + freq_extra * inv_freq_mask
self._inv_freq = inv_freq
t = mx.arange(seq_len, dtype=mx.float32)
freqs = mx.outer(t, inv_freq)
mscale = yarn_get_mscale(self.scaling_factor, self.mscale) / yarn_get_mscale(
self.scaling_factor, self.mscale_all_dim
freq_mask = 1.0 - yarn_linear_ramp_mask(low, high, dim // 2)
self._freqs = (freq_inter * freq_extra) / (
freq_inter * freq_mask + freq_extra * (1 - freq_mask)
)
self._cos_cached = mx.cos(freqs) * mscale
self._sin_cached = mx.sin(freqs) * mscale
def apply_rotary_pos_emb(self, x, cos, sin):
x1 = x[..., ::2]
x2 = x[..., 1::2]
rx1 = x1 * cos - x2 * sin
rx2 = x1 * sin + x2 * cos
return mx.concatenate([rx1, rx2], axis=-1)
def __call__(self, x, offset=0):
seq_len = offset + x.shape[2]
if self.max_seq_len_cached is None or seq_len > self.max_seq_len_cached:
self.set_cos_sin_cache(seq_len=seq_len)
if self._cos_cached.dtype != x.dtype:
self._cos_cached = self._cos_cached.astype(x.dtype)
self._sin_cached = self._sin_cached.astype(x.dtype)
return self.apply_rotary_pos_emb(
if self.mscale != 1.0:
x = self.mscale * x
return mx.fast.rope(
x,
self._cos_cached[offset:seq_len],
self._sin_cached[offset:seq_len],
x.shape[-1],
traditional=True,
base=None,
scale=1.0,
offset=offset,
freqs=self._freqs,
)

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@ -65,19 +65,16 @@ class DynamicNTKScalingRoPE(nn.Module):
self.dims = dims
self.max_position_embeddings = max_position_embeddings
self.traditional = traditional
self.original_base = base
self.scale = scale
self.rope_type = rope_type
self.rope_scaling = rope_scaling
self.base = self.compute_base_freq()
self.base = base
self.compute_freqs()
def compute_base_freq(self):
if self.rope_type == "llama3":
return self.compute_llama3_base_freq()
return self.original_base
# source: https://github.com/huggingface/transformers/blob/d5a99dfcee6e94065cb7c83cc8ab6fc5daa0cc4e/src/transformers/modeling_rope_utils.py#L318
def compute_llama3_base_freq(self):
def compute_freqs(self):
if self.rope_type != "llama3":
self._freqs = None
return
factor = self.rope_scaling["factor"]
low_freq_factor = self.rope_scaling.get("low_freq_factor", 1.0)
high_freq_factor = self.rope_scaling.get("high_freq_factor", 4.0)
@ -89,19 +86,17 @@ class DynamicNTKScalingRoPE(nn.Module):
low_freq_wavelen = old_context_len / low_freq_factor
high_freq_wavelen = old_context_len / high_freq_factor
freqs = self.original_base ** (mx.arange(0, self.dims, 2) / self.dims)
freqs = self.base ** (mx.arange(0, self.dims, 2) / self.dims)
wavelens = 2 * mx.pi * freqs
new_base_freqs = []
smooths = (wavelens - high_freq_wavelen) / (
low_freq_wavelen - high_freq_wavelen
freqs = mx.where(wavelens > low_freq_wavelen, freqs * factor, freqs)
is_medium_freq = (wavelens > high_freq_wavelen) & (wavelens < low_freq_wavelen)
smooth_factors = (old_context_len / wavelens - low_freq_factor) / (
high_freq_factor - low_freq_factor
)
new_base_freqs = freqs * (1 - smooths) * factor + smooths
new_base_freqs = mx.where(wavelens < high_freq_wavelen, freqs, new_base_freqs)
new_base_freqs = mx.where(
wavelens > low_freq_wavelen, freqs * factor, new_base_freqs
)
return new_base_freqs.mean().item()
smooth_freqs = freqs / ((1 - smooth_factors) / factor + smooth_factors)
self._freqs = mx.where(is_medium_freq, smooth_freqs, freqs)
self.base = None
def extra_repr(self):
return (
@ -111,20 +106,14 @@ class DynamicNTKScalingRoPE(nn.Module):
)
def __call__(self, x, offset: int = 0):
seq_len = x.shape[1] + offset
base = self.base
if self.max_position_embeddings and seq_len > self.max_position_embeddings:
base *= (
(self.scale * seq_len / self.max_position_embeddings) - (self.scale - 1)
) ** (self.dims / (self.dims - 2))
return mx.fast.rope(
x,
self.dims,
traditional=self.traditional,
base=base,
base=self.base,
scale=self.scale,
offset=offset,
freqs=self._freqs,
)

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@ -59,19 +59,17 @@ class Attention(nn.Module):
self.qkv_proj = nn.Linear(dim, op_size, bias=False)
self.o_proj = nn.Linear(n_heads * head_dim, dim, bias=False)
rope_scale = 1.0
if args.rope_scaling and args.rope_scaling["type"] in ["longrope", "su"]:
self.rope = SuScaledRotaryEmbedding(
head_dim,
traditional=False,
base=args.rope_theta,
scale=rope_scale,
max_position_embeddings=args.max_position_embeddings,
original_max_position_embeddings=args.original_max_position_embeddings,
short_factor=args.rope_scaling["short_factor"],
long_factor=args.rope_scaling["long_factor"],
)
else:
rope_scale = 1.0
if args.rope_scaling and args.rope_scaling["type"] == "linear":
assert isinstance(args.rope_scaling["factor"], float)
rope_scale = 1 / args.rope_scaling["factor"]

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@ -4,15 +4,14 @@ import math
from typing import List, Union
import mlx.core as mx
import mlx.nn as nn
class SuScaledRotaryEmbedding:
class SuScaledRotaryEmbedding(nn.Module):
def __init__(
self,
dims: int,
traditional: bool = False,
base: float = 10000.0,
scale: float = 1.0,
max_position_embeddings: int = 131072,
original_max_position_embeddings: int = 4096,
short_factor: Union[List[float], float] = 1.0,
@ -23,10 +22,7 @@ class SuScaledRotaryEmbedding:
Args:
dims (int): The feature dimensions to be rotated.
traditional (bool, optional): Unused. Default: ``False``.
base (int, optional): Base for the exponential scaling.
scale (float, optional): The scale used to scale the positions.
Default: ``1.0``.
max_position_embeddings (int, optional): The maximum sequence
length that this model was trained with. This is used to determine
the size of the original RoPE embeddings when using long scaling.
@ -42,40 +38,23 @@ class SuScaledRotaryEmbedding:
factors for sequences of length greater than
``original_max_position_embeddings``. Default: ``1.0``.
"""
self.inv_freq_short = 1.0 / (
mx.array(short_factor, dtype=mx.float32)
* base ** (mx.arange(0, dims, 2, dtype=mx.float32) / dims)
)
self.inv_freq_long = 1.0 / (
scale
* mx.array(long_factor, dtype=mx.float32)
* base ** (mx.arange(0, dims, 2, dtype=mx.float32) / dims)
)
super().__init__()
freqs = base ** (mx.arange(0, dims, 2, dtype=mx.float32) / dims)
self._freqs = mx.array(long_factor, dtype=mx.float32) * freqs
self.original_max_position_embeddings = original_max_position_embeddings
self.scaling_factor = math.sqrt(
self.scale = math.sqrt(
1
+ math.log(max_position_embeddings / original_max_position_embeddings)
/ math.log(original_max_position_embeddings)
)
def _get_cos_sin(self, offset, L):
position_ids = mx.arange(offset, offset + L, dtype=mx.float32)
inv_freq = (
self.inv_freq_long
if (offset + L) > self.original_max_position_embeddings
else self.inv_freq_short
)
freqs = position_ids[:, None] * inv_freq[None, :]
emb = mx.concatenate([freqs, freqs], axis=-1)
cos = mx.cos(emb) * self.scaling_factor
sin = mx.sin(emb) * self.scaling_factor
return cos, sin
def __call__(self, x, offset: int = 0):
def _rotate_half(_x):
midpoint = _x.shape[-1] // 2
x1, x2 = _x[..., :midpoint], _x[..., midpoint:]
return mx.concatenate([-x2, x1], axis=-1)
cos, sin = self._get_cos_sin(offset, x.shape[2])
return (x * cos) + (_rotate_half(x) * sin)
return mx.fast.rope(
self.scale * x,
x.shape[-1],
traditional=False,
base=None,
scale=1.0,
offset=offset,
freqs=self._freqs,
)

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@ -1,4 +1,4 @@
mlx>=0.14.1
mlx>=0.17.0
numpy
transformers[sentencepiece]>=4.39.3
protobuf

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@ -1,3 +1,3 @@
# Copyright © 2023-2024 Apple Inc.
__version__ = "0.17.0"
__version__ = "0.17.1"

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@ -110,7 +110,7 @@ class Transformer2D(nn.Module):
# Perform the input norm and projection
B, H, W, C = x.shape
x = self.norm(x.astype(mx.float32)).astype(dtype).reshape(B, -1, C)
x = self.norm(x).reshape(B, -1, C)
x = self.proj_in(x)
# Apply the transformer
@ -156,12 +156,12 @@ class ResnetBlock2D(nn.Module):
if temb is not None:
temb = self.time_emb_proj(nn.silu(temb))
y = self.norm1(x.astype(mx.float32)).astype(dtype)
y = self.norm1(x)
y = nn.silu(y)
y = self.conv1(y)
if temb is not None:
y = y + temb[:, None, None, :]
y = self.norm2(y.astype(mx.float32)).astype(dtype)
y = self.norm2(y)
y = nn.silu(y)
y = self.conv2(y)
@ -453,8 +453,7 @@ class UNetModel(nn.Module):
)
# Postprocess the output
dtype = x.dtype
x = self.conv_norm_out(x.astype(mx.float32)).astype(dtype)
x = self.conv_norm_out(x)
x = nn.silu(x)
x = self.conv_out(x)