VisualGLM-6B / lora_mixin.py
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"""
In this mixin, I use a different implementation than sat/model/finetune/lora.py
I just use a fake linear layer to replace any model with lora mixin.
"""
import torch
import torch.nn as nn
from sat.model.base_model import BaseMixin
import math
from sat.helpers import print_all
from sat.model.transformer import RowParallelLinear, ColumnParallelLinear
class HackLinear(nn.Linear):
def _load_from_state_dict(self, state_dict, prefix, local_metadata, strict, missing_keys, unexpected_keys, error_msgs):
if prefix + 'weight' in state_dict:
self.weight.data.copy_(state_dict[prefix+'weight'])
if prefix + 'bias' in state_dict:
self.bias.data.copy_(state_dict[prefix+'bias'])
class HackRowParallelLinear(RowParallelLinear):
def _load_from_state_dict(self, state_dict, prefix, local_metadata, strict, missing_keys, unexpected_keys, error_msgs):
if prefix + 'weight' in state_dict:
self.weight.data.copy_(state_dict[prefix+'weight'])
if prefix + 'bias' in state_dict:
self.bias.data.copy_(state_dict[prefix+'bias'])
class HackColumnParallelLinear(ColumnParallelLinear):
def _load_from_state_dict(self, state_dict, prefix, local_metadata, strict, missing_keys, unexpected_keys, error_msgs):
if prefix + 'weight' in state_dict:
self.weight.data.copy_(state_dict[prefix+'weight'])
if prefix + 'bias' in state_dict:
self.bias.data.copy_(state_dict[prefix+'bias'])
try:
from bitsandbytes.nn import LinearNF4
def copy_nested_list(src, dst):
for i in range(len(dst)):
if type(dst[i]) is torch.Tensor:
dst[i].copy_(src[i])
elif type(dst[i]) is list:
copy_nested_list(src[i], dst[i])
else:
dst[i] = src[i]
class HackLinearNF4(LinearNF4):
def _load_from_state_dict(self, state_dict, prefix, local_metadata, strict, missing_keys, unexpected_keys, error_msgs):
if prefix + 'weight' in state_dict:
self.weight.data.copy_(state_dict[prefix+'weight'])
if self.weight.data.dtype == torch.uint8:
copy_nested_list(state_dict[prefix+'quant_state'], self.weight.quant_state)
if prefix + 'bias' in state_dict:
self.bias.data.copy_(state_dict[prefix+'bias'])
def _save_to_state_dict(self, destination, prefix, keep_vars):
super()._save_to_state_dict(destination, prefix, keep_vars)
destination[prefix+'quant_state'] = self.weight.quant_state
except Exception as exception:
print_all("Failed to load bitsandbytes:" + str(exception), level='WARNING')
class HackParameterList(nn.ParameterList):
def _load_from_state_dict(self, state_dict, prefix, local_metadata, strict, missing_keys, unexpected_keys, error_msgs):
for i in range(len(self)):
if prefix + str(i) in state_dict:
self[i].data.copy_(state_dict[prefix+str(i)])
map_cls = {
nn.Linear: (HackLinear, {}),
ColumnParallelLinear: (HackColumnParallelLinear, {'gather_output': False}),
RowParallelLinear: (HackRowParallelLinear, {'input_is_parallel': True})
}
class LoraLinear(nn.Module):
def __init__(self, original_cls, partition, in_dim, out_dim, r, lora_alpha=1., lora_dropout=0., head_first=False, num_attention_heads=None, hidden_size_per_attention_head=None, qlora=False):
"""
You can use safely with this layer, ONLY WHEN query_key_value output is query_key_value order.
If you use a different order like ChatGLM
"""
super().__init__()
if lora_dropout and lora_dropout > 0:
self.lora_dropout = nn.Dropout(p=lora_dropout)
else:
self.lora_dropout = lambda x: x
self.r = r
self.lora_alpha = lora_alpha
self.scaling = self.lora_alpha / self.r
if qlora:
try:
self.original = HackLinearNF4(in_dim, out_dim)
except:
raise Exception('Build 4bit layer failed. You need to install the latest bitsandbytes. Try `pip install bitsandbytes`. If you still meet error after installation, try running `from bitsandbytes.nn import LinearNF4` with python and fix the error.')
else:
base_cls, kwargs = map_cls[original_cls]
self.original = base_cls(in_dim, out_dim, **kwargs)
self.matrix_A = HackParameterList([nn.Parameter(torch.empty((r, in_dim))) for _ in range(partition)])
self.matrix_B = HackParameterList([nn.Parameter(torch.empty((out_dim // partition, r))) for _ in range(partition)])
for i in range(partition):
nn.init.kaiming_uniform_(self.matrix_A[i], a=math.sqrt(5))
nn.init.zeros_(self.matrix_B[i])
self.head_first = head_first
self.partition = partition
if head_first:
assert num_attention_heads is not None and hidden_size_per_attention_head is not None, "You should set num_attention_heads and hidden_size_per_attention_head if you use head_first=True!"
self.num_attention_heads = num_attention_heads
self.hidden_size_per_attention_head = hidden_size_per_attention_head
def _load_from_state_dict(self, state_dict, prefix, local_metadata, strict, missing_keys, unexpected_keys, error_msgs):
# This is not a perfect version, becuase it doesn't handle errors and unexpected keys.
if prefix + 'weight' in state_dict:
# load from normal Linear
self.original._load_from_state_dict(state_dict, prefix, local_metadata, strict, missing_keys, unexpected_keys, error_msgs)
else:
# load from LoraLinear
super()._load_from_state_dict(state_dict, prefix, local_metadata, strict, missing_keys, unexpected_keys, error_msgs)
def forward(self, x):
mixed_raw_layer = self.original(x)
lora_outputs = []
for i in range(self.partition):
lora_outputs.append((self.lora_dropout(x) @ self.matrix_A[i].T @ self.matrix_B[i].T) * self.scaling)
if self.head_first:
new_tensor_shape = lora_outputs[0].size()[:-1] + (
self.num_attention_heads,
self.hidden_size_per_attention_head,
)
for i in range(self.partition):
lora_outputs[i] = lora_outputs[i].view(*new_tensor_shape)
mixed_raw_layer = mixed_raw_layer + torch.cat(lora_outputs, -1).view(*mixed_raw_layer.size())
else:
mixed_raw_layer = mixed_raw_layer + torch.cat(lora_outputs, -1)
return mixed_raw_layer
def replace_linear_with_lora(lin, partition, r, *args, **kw_args):
# not supported for linear without bias for now
out_dim, in_dim = lin.weight.shape
original_cls = type(lin)
del lin
return LoraLinear(original_cls, partition, in_dim, out_dim, r, *args, **kw_args)
def merge_linear_lora(lin):
if lin.original.weight.data.dtype is not torch.uint8:
weight = lin.original.weight
out_dim, in_dim = weight.shape
new_lin = nn.Linear(in_dim, out_dim)
else:
import bitsandbytes.functional as F
weight = F.dequantize_fp4(lin.original.weight.data, lin.original.weight.quant_state).to(lin.original.bias.data.dtype)
out_dim, in_dim = weight.shape
new_lin = HackLinearNF4(in_dim, out_dim)
new_lin.bias.data = lin.original.bias.data
new_qkv = []
for i in range(lin.partition):
new_qkv.append(lin.matrix_A[i].data.T.float() @ lin.matrix_B[i].data.T.float() * lin.scaling)
if lin.head_first:
ini_shape = new_qkv[0].shape
new_qkv = [x.view(ini_shape[0], lin.num_attention_heads, -1) for x in new_qkv]
new_qkv = torch.cat(new_qkv, -1).view(ini_shape[0], lin.partition*ini_shape[1])
else:
new_qkv = torch.cat(new_qkv, -1)
new_lin.weight.data = weight + new_qkv.T.to(lin.original.bias.data.dtype)
return new_lin.cuda() if torch.cuda.is_available() else new_lin
class LoraMixin(BaseMixin):
def __init__(self,
layer_num,
r: int = 0,
lora_alpha: int = 1,
lora_dropout: float = 0.,
layer_range = None,
head_first = False,
num_attention_heads = None,
hidden_size_per_attention_head = None,
qlora = False,
cross_attention = True):
super().__init__()
self.r = r
self.lora_alpha = lora_alpha
self.lora_dropout = lora_dropout
if layer_range is None:
layer_range = [i for i in range(layer_num)]
self.layer_range = layer_range
self.scaling = self.lora_alpha / self.r
self.head_first = head_first
self.num_attention_heads = num_attention_heads
self.hidden_size_per_attention_head = hidden_size_per_attention_head
self.qlora = qlora
self.cross_attention = cross_attention
def reinit(self, parent_model):
for i in self.layer_range:
print(f'replacing layer {i} attention with lora')
parent_model.transformer.layers[i].attention.dense = replace_linear_with_lora(parent_model.transformer.layers[i].attention.dense, 1, self.r, self.lora_alpha, self.lora_dropout, qlora=self.qlora)
parent_model.transformer.layers[i].attention.query_key_value = replace_linear_with_lora(parent_model.transformer.layers[i].attention.query_key_value, 3, self.r, self.lora_alpha, self.lora_dropout, head_first=self.head_first, num_attention_heads=self.num_attention_heads, hidden_size_per_attention_head=self.hidden_size_per_attention_head, qlora=self.qlora)
if self.cross_attention and parent_model.transformer.layers[i].is_decoder:
print(f'replacing layer {i} cross attention with lora')
parent_model.transformer.layers[i].cross_attention.dense = replace_linear_with_lora(parent_model.transformer.layers[i].cross_attention.dense, 1, self.r, self.lora_alpha, self.lora_dropout, qlora=self.qlora)
parent_model.transformer.layers[i].cross_attention.query = replace_linear_with_lora(parent_model.transformer.layers[i].cross_attention.query, 1, self.r, self.lora_alpha, self.lora_dropout, qlora=self.qlora)
parent_model.transformer.layers[i].cross_attention.key_value = replace_linear_with_lora(parent_model.transformer.layers[i].cross_attention.key_value, 2, self.r, self.lora_alpha, self.lora_dropout, qlora=self.qlora)
if self.qlora:
print('replacing chatglm linear layer with 4bit')
def replace_linear_with_nf4(model, name=None, cache={}):
if type(model) in (nn.Linear, RowParallelLinear, ColumnParallelLinear):
out_dim, in_dim = model.weight.shape
return HackLinearNF4(in_dim, out_dim)
names = set()
for name, child in model.named_children():
if name not in names:
if child in cache:
new_child = cache[child]
else:
new_child = replace_linear_with_nf4(child, name=name, cache=cache)
cache[child] = new_child
setattr(model, name, new_child)
names.add(name)
flag = True
while flag:
flag = False
for name, child in model.named_children():
if name not in names:
setattr(model, name, cache[child])
names.add(name)
flag = True
return model
replace_linear_with_nf4(parent_model.transformer, None, {})
def merge_lora(self):
for i in self.layer_range:
print(f'merge layer {i} lora attention back to linear')
self.transformer.layers[i].attention.dense = merge_linear_lora(self.transformer.layers[i].attention.dense)
self.transformer.layers[i].attention.query_key_value = merge_linear_lora(self.transformer.layers[i].attention.query_key_value)
if self.transformer.layers[i].is_decoder:
print(f'merge layer {i} lora cross attention back to linear')
self.transformer.layers[i].cross_attention.dense = merge_linear_lora(self.transformer.layers[i].cross_attention.dense)
self.transformer.layers[i].cross_attention.query = merge_linear_lora(self.transformer.layers[i].cross_attention.query)
self.transformer.layers[i].cross_attention.key_value = merge_linear_lora(self.transformer.layers[i].cross_attention.key_value)
if __name__ == '__main__':
class Model(nn.Module):
def __init__(self):
super().__init__()
self.child = nn.Linear(100, 200)
def forward(self, x):
return self.child(x)
model = Model()
torch.save(model.state_dict(), "linear.pt")
x = torch.randn(2, 100)
out1 = model(x)
model.child = LoraLinear(100, 200, 10)
model.load_state_dict(torch.load("linear.pt"), strict=False)
out2 = model(x)
torch.save(model.state_dict(), "lora.pt")
ckpt = torch.load("lora.pt")
breakpoint()
model.load_state_dict(ckpt, strict=False)
out3 = model(x)
breakpoint()