mlx-examples/llms/mlx_lm/tuner/lora.py
Zai Thottakath 4e01700816
Allow the entire model to be targed for LoRA and DoRA fine tuning: LoRA and DoRA embeddings with small DoRALinear bug fix (#914)
* feature: LoRA adapter for Embeddings

* feature: wire in LoRAEmbedding into the tuner. Allow the embedding and non model.layers Linear layers to be targeted for fine tuning

* feature: DoRA adapter for Embeddings

* feature: wire in DoRAEmbedding

* bugfix: ensure self.m is recalculated when the linear layer is changed in DoRALinear.from_linear

* refactor: prefer from_base over from_linear or from_embedding. prefer fuse over to_linear or to_embedding

* cleanup: remove unused imports in test_dora.py

* refactor: remove unnecessary non_layer_modules

* cleanup: remove wrong comments for lora embedding dropout. remove uncessary parens in dora embedding dropout

* nits

---------

Co-authored-by: Awni Hannun <awni@apple.com>
2024-08-16 07:38:36 -07:00

286 lines
8.2 KiB
Python

# Copyright © 2024 Apple Inc.
import math
import mlx.core as mx
import mlx.nn as nn
from ..models.switch_layers import QuantizedSwitchLinear, SwitchLinear
class LoRALinear(nn.Module):
@staticmethod
def from_base(
linear: nn.Linear,
r: int = 8,
dropout: float = 0.0,
scale: float = 20.0,
):
# TODO remove when input_dims and output_dims are attributes
# on linear and quantized linear
output_dims, input_dims = linear.weight.shape
if isinstance(linear, nn.QuantizedLinear):
input_dims *= 32 // linear.bits
lora_lin = LoRALinear(
input_dims=input_dims,
output_dims=output_dims,
r=r,
dropout=dropout,
scale=scale,
)
lora_lin.linear = linear
return lora_lin
def fuse(self, de_quantize: bool = False):
linear = self.linear
bias = "bias" in linear
weight = linear.weight
is_quantized = isinstance(linear, nn.QuantizedLinear)
# Use the same type as the linear weight if not quantized
dtype = weight.dtype
if is_quantized:
dtype = linear.scales.dtype
weight = mx.dequantize(
weight,
linear.scales,
linear.biases,
linear.group_size,
linear.bits,
)
output_dims, input_dims = weight.shape
fused_linear = nn.Linear(input_dims, output_dims, bias=bias)
lora_b = (self.scale * self.lora_b.T).astype(dtype)
lora_a = self.lora_a.T.astype(dtype)
fused_linear.weight = weight + lora_b @ lora_a
if bias:
fused_linear.bias = linear.bias
if is_quantized and not de_quantize:
fused_linear = nn.QuantizedLinear.from_linear(
fused_linear,
linear.group_size,
linear.bits,
)
return fused_linear
def __init__(
self,
input_dims: int,
output_dims: int,
r: int = 8,
dropout: float = 0.0,
scale: float = 20.0,
bias: bool = False,
):
super().__init__()
# Regular linear layer weights
self.linear = nn.Linear(input_dims, output_dims, bias=bias)
self.dropout = nn.Dropout(p=dropout)
# Scale for low-rank update
self.scale = scale
# Low rank lora weights
scale = 1 / math.sqrt(input_dims)
self.lora_a = mx.random.uniform(
low=-scale,
high=scale,
shape=(input_dims, r),
)
self.lora_b = mx.zeros(shape=(r, output_dims))
def __call__(self, x):
y = self.linear(x)
z = (self.dropout(x) @ self.lora_a) @ self.lora_b
return y + (self.scale * z).astype(x.dtype)
class LoRASwitchLinear(nn.Module):
@staticmethod
def from_base(
linear: nn.Module,
r: int = 8,
dropout: float = 0.0,
scale: float = 20.0,
):
lora_lin = LoRASwitchLinear(
input_dims=linear.input_dims,
output_dims=linear.output_dims,
num_experts=linear.num_experts,
r=r,
dropout=dropout,
scale=scale,
)
lora_lin.linear = linear
return lora_lin
def fuse(self, de_quantize: bool = False):
linear = self.linear
bias = "bias" in linear
weight = linear.weight
is_quantized = isinstance(linear, QuantizedSwitchLinear)
# Use the same type as the linear weight if not quantized
dtype = weight.dtype
if is_quantized:
dtype = mx.float16
weight = mx.dequantize(
weight,
linear.scales,
linear.biases,
linear.group_size,
linear.bits,
)
num_experts, output_dims, input_dims = weight.shape
fused_linear = SwitchLinear(input_dims, output_dims, num_experts, bias=bias)
lora_b = (self.scale * self.lora_b).astype(dtype)
lora_a = self.lora_a.reshape(num_experts, -1, input_dims).astype(dtype)
fused_linear.weight = weight + lora_b @ lora_a
if bias:
fused_linear.bias = linear.bias
if is_quantized and not de_quantize:
fused_linear = fused_linear.to_quantized(linear.group_size, linear.bits)
return fused_linear
def __init__(
self,
input_dims: int,
output_dims: int,
num_experts: int,
r: int = 8,
dropout: float = 0.0,
scale: float = 20.0,
bias: bool = False,
):
super().__init__()
# Regular linear layer weights
self.linear = SwitchLinear(input_dims, output_dims, num_experts, bias=bias)
self.dropout = nn.Dropout(p=dropout)
# Scale for low-rank update
self.scale = scale
# Low rank lora weights
scale = 1 / math.sqrt(input_dims)
self.lora_a = mx.random.uniform(
low=-scale,
high=scale,
shape=(r * num_experts, input_dims),
)
self.lora_b = mx.zeros(shape=(num_experts, output_dims, r))
self.num_experts = num_experts
def __call__(self, x, indices):
shape = x.shape[:-3] + (self.num_experts, -1)
y = self.linear(x, indices)
z = (self.dropout(x) @ self.lora_a.T).reshape(shape)
z = mx.take_along_axis(z, indices[..., None], axis=-2)
z = z[..., None, :] @ self.lora_b[indices].swapaxes(-2, -1)
return y + (self.scale * z).astype(x.dtype)
class LoRAEmbedding(nn.Module):
@staticmethod
def from_base(
embedding: nn.Embedding,
r: int = 8,
dropout: float = 0.0,
scale: float = 20.0,
):
num_embeddings, dims = embedding.weight.shape
if isinstance(embedding, nn.QuantizedEmbedding):
dims *= 32 // embedding.bits
lora_embedding = LoRAEmbedding(
num_embeddings=num_embeddings,
dims=dims,
r=r,
dropout=dropout,
scale=scale,
)
lora_embedding.embedding = embedding
return lora_embedding
def fuse(self, de_quantize: bool = False):
embedding = self.embedding
weight = embedding.weight
is_quantized = isinstance(embedding, nn.QuantizedEmbedding)
# Use the same type as the linear weight if not quantized
dtype = weight.dtype
if is_quantized:
dtype = embedding.scales.dtype
weight = mx.dequantize(
weight,
embedding.scales,
embedding.biases,
embedding.group_size,
embedding.bits,
)
num_embeddings, dims = weight.shape
fused_embedding = nn.Embedding(num_embeddings, dims)
lora_a = (self.scale * self.lora_a).astype(dtype)
lora_b = self.lora_b.astype(dtype)
fused_embedding.weight = weight + lora_a @ lora_b
if is_quantized and not de_quantize:
fused_embedding = nn.QuantizedEmbedding.from_embedding(
fused_embedding,
embedding.group_size,
embedding.bits,
)
return fused_embedding
def __init__(
self,
num_embeddings: int,
dims: int,
r: int = 8,
dropout: float = 0.0,
scale: float = 20.0,
):
super().__init__()
# Regular embedding layer
self.embedding = nn.Embedding(num_embeddings, dims)
self.dropout = nn.Dropout(p=dropout)
# Scale for low-rank update
self.scale = scale
# Low rank lora weights
scale = 1 / math.sqrt(num_embeddings)
self.lora_a = mx.random.uniform(
low=-scale,
high=scale,
shape=(num_embeddings, r),
)
self.lora_b = mx.zeros(shape=(r, dims))
def __call__(self, x):
y = self.embedding(x)
z = self.dropout(self.lora_a[x] @ self.lora_b)
out = y + (self.scale * z).astype(y.dtype)
return out
def as_linear(self, x):
y = self.embedding.as_linear(x)
z = (self.dropout(x) @ self.lora_b.T) @ self.lora_a.T
return y + (self.scale * z).astype(x.dtype)