File size: 5,803 Bytes
c295391
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
# MIT License

# Copyright (c) Microsoft

# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:

# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.

# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

# Copyright (c) [2025] [Microsoft]
# Copyright (c) [2025] [Chongjie Ye] 
# SPDX-License-Identifier: MIT
# This file has been modified by Chongjie Ye on 2025/04/10
# Original file was released under MIT, with the full license text # available at https://github.com/atong01/conditional-flow-matching/blob/1.0.7/LICENSE.
# This modified file is released under the same license.
from typing import *
import torch
import torch.nn as nn
from ...modules.utils import convert_module_to_f16, convert_module_to_f32
from ...modules import sparse as sp
from ...modules.transformer import AbsolutePositionEmbedder
from ...modules.sparse.transformer import SparseTransformerBlock


def block_attn_config(self):
    """
    Return the attention configuration of the model.
    """
    for i in range(self.num_blocks):
        if self.attn_mode == "shift_window":
            yield "serialized", self.window_size, 0, (16 * (i % 2),) * 3, sp.SerializeMode.Z_ORDER
        elif self.attn_mode == "shift_sequence":
            yield "serialized", self.window_size, self.window_size // 2 * (i % 2), (0, 0, 0), sp.SerializeMode.Z_ORDER
        elif self.attn_mode == "shift_order":
            yield "serialized", self.window_size, 0, (0, 0, 0), sp.SerializeModes[i % 4]
        elif self.attn_mode == "full":
            yield "full", None, None, None, None
        elif self.attn_mode == "swin":
            yield "windowed", self.window_size, None, self.window_size // 2 * (i % 2), None


class SparseTransformerBase(nn.Module):
    """
    Sparse Transformer without output layers.
    Serve as the base class for encoder and decoder.
    """
    def __init__(
        self,
        in_channels: int,
        model_channels: int,
        num_blocks: int,
        num_heads: Optional[int] = None,
        num_head_channels: Optional[int] = 64,
        mlp_ratio: float = 4.0,
        attn_mode: Literal["full", "shift_window", "shift_sequence", "shift_order", "swin"] = "full",
        window_size: Optional[int] = None,
        pe_mode: Literal["ape", "rope"] = "ape",
        use_fp16: bool = False,
        use_checkpoint: bool = False,
        qk_rms_norm: bool = False,
    ):
        super().__init__()
        self.in_channels = in_channels
        self.model_channels = model_channels
        self.num_blocks = num_blocks
        self.window_size = window_size
        self.num_heads = num_heads or model_channels // num_head_channels
        self.mlp_ratio = mlp_ratio
        self.attn_mode = attn_mode
        self.pe_mode = pe_mode
        self.use_fp16 = use_fp16
        self.use_checkpoint = use_checkpoint
        self.qk_rms_norm = qk_rms_norm
        self.dtype = torch.float16 if use_fp16 else torch.float32

        if pe_mode == "ape":
            self.pos_embedder = AbsolutePositionEmbedder(model_channels)

        self.input_layer = sp.SparseLinear(in_channels, model_channels)
        self.blocks = nn.ModuleList([
            SparseTransformerBlock(
                model_channels,
                num_heads=self.num_heads,
                mlp_ratio=self.mlp_ratio,
                attn_mode=attn_mode,
                window_size=window_size,
                shift_sequence=shift_sequence,
                shift_window=shift_window,
                serialize_mode=serialize_mode,
                use_checkpoint=self.use_checkpoint,
                use_rope=(pe_mode == "rope"),
                qk_rms_norm=self.qk_rms_norm,
            )
            for attn_mode, window_size, shift_sequence, shift_window, serialize_mode in block_attn_config(self)
        ])

    @property
    def device(self) -> torch.device:
        """
        Return the device of the model.
        """
        return next(self.parameters()).device

    def convert_to_fp16(self) -> None:
        """
        Convert the torso of the model to float16.
        """
        self.blocks.apply(convert_module_to_f16)

    def convert_to_fp32(self) -> None:
        """
        Convert the torso of the model to float32.
        """
        self.blocks.apply(convert_module_to_f32)

    def initialize_weights(self) -> None:
        # Initialize transformer layers:
        def _basic_init(module):
            if isinstance(module, nn.Linear):
                torch.nn.init.xavier_uniform_(module.weight)
                if module.bias is not None:
                    nn.init.constant_(module.bias, 0)
        self.apply(_basic_init)

    def forward(self, x: sp.SparseTensor) -> sp.SparseTensor:
        h = self.input_layer(x)
        if self.pe_mode == "ape":
            h = h + self.pos_embedder(x.coords[:, 1:])
        h = h.type(self.dtype)
        for block in self.blocks:
            h = block(h)
        return h