English
OneScience
protein structure generation
File size: 7,377 Bytes
8e04e6f
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
from typing import Dict

import einops
import torch

from onescience.utils.openfold.np.residue_constants import RESTYPE_ATOM37_MASK
from models.nn.feature_factory import FeatureFactory
from models.nn.modules.attn_n_transition import MultiheadAttnAndTransition
from models.nn.modules.pair_update import PairReprUpdate
from models.nn.modules.seq_transition_af3 import Transition


def get_atom_mask(device: torch.device = None):
    return torch.from_numpy(RESTYPE_ATOM37_MASK).to(
        dtype=torch.bool, device=device
    )  # [21, 37]


class DecoderTransformer(torch.nn.Module):
    """
    Encoder part of the autoencoder. A transformer with pair-biased attention.
    """

    def __init__(self, **kwargs):
        """
        Initializes the NN. The seqs and pair representations used are just zero in case
        no features are required."""
        super(DecoderTransformer, self).__init__()
        self.nlayers = kwargs["decoder"]["nlayers"]
        self.token_dim = kwargs["decoder"]["token_dim"]
        self.pair_repr_dim = kwargs["decoder"]["pair_repr_dim"]
        self.update_pair_repr = kwargs["decoder"]["update_pair_repr"]
        self.update_pair_repr_every_n = kwargs["decoder"]["update_pair_repr_every_n"]
        self.use_tri_mult = kwargs["decoder"]["use_tri_mult"]
        self.use_qkln = kwargs["decoder"]["use_qkln"]
        self.abs_coors = kwargs["decoder"].get("abs_coors", True)

        # To form initial representation
        self.init_repr_factory = FeatureFactory(
            feats=kwargs["decoder"]["feats_seq"],
            dim_feats_out=kwargs["decoder"]["token_dim"],
            use_ln_out=False,
            mode="seq",
            **kwargs["decoder"],
        )

        # To get conditioning variables
        self.cond_factory = FeatureFactory(
            feats=kwargs["decoder"]["feats_cond_seq"],
            dim_feats_out=kwargs["decoder"]["dim_cond"],
            use_ln_out=False,
            mode="seq",
            **kwargs["decoder"],
        )

        self.transition_c_1 = Transition(
            kwargs["decoder"]["dim_cond"], expansion_factor=2
        )
        self.transition_c_2 = Transition(
            kwargs["decoder"]["dim_cond"], expansion_factor=2
        )

        # To get pair representation
        self.pair_rep_factory = FeatureFactory(
            feats=kwargs["decoder"]["feats_pair_repr"],
            dim_feats_out=kwargs["decoder"]["pair_repr_dim"],
            use_ln_out=False,
            mode="pair",
            **kwargs["decoder"],
        )

        # Trunk layers
        self.transformer_layers = torch.nn.ModuleList(
            [
                MultiheadAttnAndTransition(
                    dim_token=self.token_dim,
                    dim_pair=self.pair_repr_dim,
                    nheads=kwargs["decoder"]["nheads"],
                    dim_cond=kwargs["decoder"]["dim_cond"],
                    residual_mha=True,
                    residual_transition=True,
                    parallel_mha_transition=False,
                    use_attn_pair_bias=True,
                    use_qkln=self.use_qkln,
                )
                for _ in range(self.nlayers)
            ]
        )

        # To update pair representations if needed
        if self.update_pair_repr:
            self.pair_update_layers = torch.nn.ModuleList(
                [
                    (
                        PairReprUpdate(
                            token_dim=kwargs["decoder"]["token_dim"],
                            pair_dim=kwargs["decoder"]["pair_repr_dim"],
                            use_tri_mult=self.use_tri_mult,
                        )
                        if i % self.update_pair_repr_every_n == 0
                        else None
                    )
                    for i in range(self.nlayers - 1)
                ]
            )

        self.logit_linear = torch.nn.Sequential(
            torch.nn.LayerNorm(self.token_dim),
            torch.nn.Linear(self.token_dim, 20, bias=False),
        )
        self.struct_linear = torch.nn.Sequential(
            torch.nn.LayerNorm(self.token_dim),
            torch.nn.Linear(self.token_dim, int(37 * 3), bias=False),
        )

    def forward(self, input: Dict[str, torch.Tensor]) -> Dict[str, torch.Tensor]:
        """
        Runs the network.

        Args:
            input: {
                "z_latent": torch.Tensor(b, n, latent_dim),
                "ca_coors_nm": torch.Tensor(b, n, 3),
                "residue_mask": boolean torch.Tensor(b, n)
            }

        Returns:
            Dictionary:
            {
                "coors_nm": all atom coordinates, shape [b, n, 37, 3]
                "seq_logits": logits for the residue types, shape [b, n, 20]
                "residue_mask": boolean [b, n]
                "aatype_max": residue type by taking the most likely logit, shape [b, n], with integer values {0, ..., 19}
                "atom_mask": boolean [b, n, 37], atom37 mask corresponding to aatype_max
            }
        """
        ca_coors_nm = input["ca_coors_nm"]  # [b, n, 3]
        mask = input["residue_mask"]  # [b, n] boolean

        # Conditioning variables
        c = self.cond_factory(input)  # [b, n, dim_cond]
        c = self.transition_c_2(self.transition_c_1(c, mask), mask)  # [b, n, dim_cond]

        # Iinitial sequence representation from features
        seq_f_repr = self.init_repr_factory(input)  # [b, n, token_dim]
        seqs = seq_f_repr * mask[..., None]  # [b, n, token_dim]

        pair_rep = self.pair_rep_factory(input)  # [b, n, n, pair_dim]

        # Run trunk
        for i in range(self.nlayers):
            seqs = self.transformer_layers[i](
                seqs, pair_rep, c, mask
            )  # [b, n, token_dim]

            if self.update_pair_repr:
                if i < self.nlayers - 1:
                    if self.pair_update_layers[i] is not None:
                        pair_rep = self.pair_update_layers[i](
                            seqs, pair_rep, mask
                        )  # [b, n, n, pair_dim]

        # Get logits
        logits_out = self.logit_linear(seqs) * mask[..., None]  # [b, n, 20]

        # Get coordinates
        coors_flat_nm = self.struct_linear(seqs) * mask[..., None]  # [b, n, 37 * 3]
        coors_a37_nm = einops.rearrange(
            coors_flat_nm, "b n (a t) -> b n a t", a=37, t=3
        )  # [b, n, 37, 3]

        if self.abs_coors:
            coors_a37_nm[..., 1, :] = coors_a37_nm[..., 1, :] * 0.0 + ca_coors_nm
        else:
            coors_a37_nm[..., 1, :] = coors_a37_nm[..., 1, :] * 0.0
            coors_a37_nm = coors_a37_nm + ca_coors_nm[:, :, None, :]  # [b, n, 37, 3]

        # Get sequence
        aatype_max = torch.argmax(logits_out, dim=-1)  # [b, n]
        aatype_max = aatype_max * mask  # [b, n]

        # Get atom_mask
        aa_a37_mask = get_atom_mask(device=logits_out.device)  # [21, 37] boolean
        atom_mask = aa_a37_mask[aatype_max, :]  # [b, n, 37] boolean
        atom_mask = atom_mask * mask[..., None]  # [b, n, 37] boolean

        output = {
            "coors_nm": coors_a37_nm,  # [b, n, 37, 3]
            "seq_logits": logits_out,  # [b, n, 20]
            "residue_mask": mask,  # [b, n]
            "aatype_max": aatype_max,  # [b, n]
            "atom_mask": atom_mask,  # [b, n, 37]
        }
        return output