flash-attention/flash_attn/modules/mlp.py
2023-07-26 09:39:37 -10:00

117 lines
4.9 KiB
Python

# Copyright (c) 2022, Tri Dao.
import torch
import torch.nn as nn
import torch.nn.functional as F
from torch.distributed import ProcessGroup
try:
from flash_attn.ops.fused_dense import ColumnParallelLinear, RowParallelLinear
except ImportError:
ColumnParallelLinear, RowParallelLinear = None, None
try:
from flash_attn.ops.fused_dense import FusedMLP, ParallelFusedMLP
except ImportError:
FusedMLP, ParallelFusedMLP = None, None
class Mlp(nn.Module):
def __init__(self, in_features, hidden_features=None, out_features=None, activation=F.gelu,
bias1=True, bias2=True, return_residual=False, device=None, dtype=None):
factory_kwargs = {'device': device, 'dtype': dtype}
super().__init__()
out_features = out_features or in_features
hidden_features = hidden_features or in_features * 4
self.return_residual = return_residual
self.fc1 = nn.Linear(in_features, hidden_features, bias=bias1, **factory_kwargs)
self.activation = activation
self.fc2 = nn.Linear(hidden_features, out_features, bias=bias2, **factory_kwargs)
def forward(self, x):
y = self.fc1(x)
y = self.activation(y)
y = self.fc2(y)
return y if not self.return_residual else (y, x)
class ParallelMLP(nn.Module):
def __init__(self, in_features, hidden_features=None, out_features=None, activation=F.gelu,
process_group: ProcessGroup = None, sequence_parallel=True,
bias1=True, bias2=True, device=None, dtype=None):
factory_kwargs = {'device': device, 'dtype': dtype}
super().__init__()
assert ColumnParallelLinear is not None, "Need to install fused_dense"
assert RowParallelLinear is not None, "Need to install fused_dense"
out_features = out_features or in_features
hidden_features = hidden_features or in_features * 4
self.fc1 = ColumnParallelLinear(in_features, hidden_features, process_group, bias=bias1,
sequence_parallel=sequence_parallel, **factory_kwargs)
self.activation = activation
self.fc2 = RowParallelLinear(hidden_features, out_features, process_group, bias=bias2,
sequence_parallel=sequence_parallel, **factory_kwargs)
def forward(self, x):
y = self.fc1(x)
y = self.activation(y)
y = self.fc2(y)
return y
class GatedMlp(nn.Module):
def __init__(self, in_features, hidden_features=None, out_features=None, activation=F.sigmoid,
bias1=True, bias2=True, multiple_of=256, return_residual=False,
device=None, dtype=None):
factory_kwargs = {'device': device, 'dtype': dtype}
super().__init__()
out_features = out_features or in_features
hidden_features = hidden_features or int(8 * in_features / 3)
hidden_features = (hidden_features + multiple_of - 1) // multiple_of * multiple_of
self.return_residual = return_residual
self.fc1 = nn.Linear(in_features, 2 * hidden_features, bias=bias1, **factory_kwargs)
self.activation = activation
self.fc2 = nn.Linear(hidden_features, out_features, bias=bias2, **factory_kwargs)
def forward(self, x):
y = self.fc1(x)
if self.activation == F.sigmoid: # Special case for GLU
y = F.glu(y, dim=-1)
else:
y, gate = y.chunk(2, dim=-1)
y = y * self.activation(gate)
y = self.fc2(y)
return y if not self.return_residual else (y, x)
class ParallelGatedMlp(nn.Module):
""" Parallel GatedMlp """
def __init__(self, in_features, process_group, hidden_features=None, out_features=None,
activation=F.sigmoid, bias1=True, bias2=True, multiple_of=256,
sequence_parallel=True, device=None, dtype=None):
factory_kwargs = {'device': device, 'dtype': dtype}
super().__init__()
out_features = out_features or in_features
hidden_features = hidden_features or int(8 * in_features / 3)
hidden_features = (hidden_features + multiple_of - 1) // multiple_of * multiple_of
if ColumnParallelLinear is None or RowParallelLinear is None:
raise ImportError('fused_dense is not installed')
self.fc1 = ColumnParallelLinear(in_features, 2 * hidden_features, process_group, bias=bias1,
sequence_parallel=sequence_parallel, **factory_kwargs)
self.activation = activation
self.fc2 = RowParallelLinear(hidden_features, out_features, process_group, bias=bias2,
sequence_parallel=sequence_parallel, **factory_kwargs)
def forward(self, x):
y = self.fc1(x)
if self.activation == F.sigmoid: # Special case for GLU
y = F.glu(y, dim=-1)
else:
y, gate = y.chunk(2, dim=-1)
y = y * self.activation(gate)
y = self.fc2(y)
return y