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@ -19,45 +19,6 @@ from ..attention import SpatialTransformer
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from comfy.ldm.util import exists |
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# dummy replace |
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def convert_module_to_f16(x): |
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pass |
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def convert_module_to_f32(x): |
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pass |
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## go |
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class AttentionPool2d(nn.Module): |
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""" |
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Adapted from CLIP: https://github.com/openai/CLIP/blob/main/clip/model.py |
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""" |
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def __init__( |
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self, |
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spacial_dim: int, |
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embed_dim: int, |
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num_heads_channels: int, |
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output_dim: int = None, |
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): |
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super().__init__() |
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self.positional_embedding = nn.Parameter(th.randn(embed_dim, spacial_dim ** 2 + 1) / embed_dim ** 0.5) |
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self.qkv_proj = conv_nd(1, embed_dim, 3 * embed_dim, 1) |
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self.c_proj = conv_nd(1, embed_dim, output_dim or embed_dim, 1) |
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self.num_heads = embed_dim // num_heads_channels |
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self.attention = QKVAttention(self.num_heads) |
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def forward(self, x): |
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b, c, *_spatial = x.shape |
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x = x.reshape(b, c, -1) # NC(HW) |
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x = th.cat([x.mean(dim=-1, keepdim=True), x], dim=-1) # NC(HW+1) |
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x = x + self.positional_embedding[None, :, :].to(x.dtype) # NC(HW+1) |
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x = self.qkv_proj(x) |
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x = self.attention(x) |
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x = self.c_proj(x) |
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return x[:, :, 0] |
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class TimestepBlock(nn.Module): |
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""" |
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Any module where forward() takes timestep embeddings as a second argument. |
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@ -138,19 +99,6 @@ class Upsample(nn.Module):
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x = self.conv(x) |
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return x |
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class TransposedUpsample(nn.Module): |
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'Learned 2x upsampling without padding' |
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def __init__(self, channels, out_channels=None, ks=5): |
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super().__init__() |
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self.channels = channels |
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self.out_channels = out_channels or channels |
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self.up = nn.ConvTranspose2d(self.channels,self.out_channels,kernel_size=ks,stride=2) |
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def forward(self,x): |
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return self.up(x) |
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class Downsample(nn.Module): |
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""" |
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A downsampling layer with an optional convolution. |
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@ -296,142 +244,6 @@ class ResBlock(TimestepBlock):
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h = self.out_layers(h) |
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return self.skip_connection(x) + h |
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class AttentionBlock(nn.Module): |
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""" |
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An attention block that allows spatial positions to attend to each other. |
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Originally ported from here, but adapted to the N-d case. |
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https://github.com/hojonathanho/diffusion/blob/1e0dceb3b3495bbe19116a5e1b3596cd0706c543/diffusion_tf/models/unet.py#L66. |
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""" |
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def __init__( |
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self, |
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channels, |
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num_heads=1, |
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num_head_channels=-1, |
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use_checkpoint=False, |
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use_new_attention_order=False, |
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): |
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super().__init__() |
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self.channels = channels |
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if num_head_channels == -1: |
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self.num_heads = num_heads |
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else: |
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assert ( |
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channels % num_head_channels == 0 |
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), f"q,k,v channels {channels} is not divisible by num_head_channels {num_head_channels}" |
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self.num_heads = channels // num_head_channels |
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self.use_checkpoint = use_checkpoint |
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self.norm = normalization(channels) |
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self.qkv = conv_nd(1, channels, channels * 3, 1) |
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if use_new_attention_order: |
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# split qkv before split heads |
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self.attention = QKVAttention(self.num_heads) |
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else: |
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# split heads before split qkv |
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self.attention = QKVAttentionLegacy(self.num_heads) |
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self.proj_out = zero_module(conv_nd(1, channels, channels, 1)) |
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def forward(self, x): |
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return checkpoint(self._forward, (x,), self.parameters(), True) # TODO: check checkpoint usage, is True # TODO: fix the .half call!!! |
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#return pt_checkpoint(self._forward, x) # pytorch |
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def _forward(self, x): |
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b, c, *spatial = x.shape |
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x = x.reshape(b, c, -1) |
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qkv = self.qkv(self.norm(x)) |
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h = self.attention(qkv) |
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h = self.proj_out(h) |
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return (x + h).reshape(b, c, *spatial) |
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def count_flops_attn(model, _x, y): |
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""" |
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A counter for the `thop` package to count the operations in an |
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attention operation. |
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Meant to be used like: |
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macs, params = thop.profile( |
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model, |
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inputs=(inputs, timestamps), |
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custom_ops={QKVAttention: QKVAttention.count_flops}, |
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) |
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""" |
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b, c, *spatial = y[0].shape |
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num_spatial = int(np.prod(spatial)) |
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# We perform two matmuls with the same number of ops. |
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# The first computes the weight matrix, the second computes |
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# the combination of the value vectors. |
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matmul_ops = 2 * b * (num_spatial ** 2) * c |
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model.total_ops += th.DoubleTensor([matmul_ops]) |
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class QKVAttentionLegacy(nn.Module): |
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""" |
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A module which performs QKV attention. Matches legacy QKVAttention + input/ouput heads shaping |
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""" |
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def __init__(self, n_heads): |
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super().__init__() |
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self.n_heads = n_heads |
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def forward(self, qkv): |
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""" |
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Apply QKV attention. |
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:param qkv: an [N x (H * 3 * C) x T] tensor of Qs, Ks, and Vs. |
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:return: an [N x (H * C) x T] tensor after attention. |
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""" |
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bs, width, length = qkv.shape |
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assert width % (3 * self.n_heads) == 0 |
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ch = width // (3 * self.n_heads) |
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q, k, v = qkv.reshape(bs * self.n_heads, ch * 3, length).split(ch, dim=1) |
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scale = 1 / math.sqrt(math.sqrt(ch)) |
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weight = th.einsum( |
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"bct,bcs->bts", q * scale, k * scale |
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) # More stable with f16 than dividing afterwards |
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weight = th.softmax(weight.float(), dim=-1).type(weight.dtype) |
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a = th.einsum("bts,bcs->bct", weight, v) |
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return a.reshape(bs, -1, length) |
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@staticmethod |
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def count_flops(model, _x, y): |
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return count_flops_attn(model, _x, y) |
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class QKVAttention(nn.Module): |
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""" |
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A module which performs QKV attention and splits in a different order. |
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""" |
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def __init__(self, n_heads): |
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super().__init__() |
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self.n_heads = n_heads |
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def forward(self, qkv): |
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""" |
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Apply QKV attention. |
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:param qkv: an [N x (3 * H * C) x T] tensor of Qs, Ks, and Vs. |
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:return: an [N x (H * C) x T] tensor after attention. |
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""" |
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bs, width, length = qkv.shape |
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assert width % (3 * self.n_heads) == 0 |
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ch = width // (3 * self.n_heads) |
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q, k, v = qkv.chunk(3, dim=1) |
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scale = 1 / math.sqrt(math.sqrt(ch)) |
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weight = th.einsum( |
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"bct,bcs->bts", |
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(q * scale).view(bs * self.n_heads, ch, length), |
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(k * scale).view(bs * self.n_heads, ch, length), |
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) # More stable with f16 than dividing afterwards |
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weight = th.softmax(weight.float(), dim=-1).type(weight.dtype) |
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a = th.einsum("bts,bcs->bct", weight, v.reshape(bs * self.n_heads, ch, length)) |
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return a.reshape(bs, -1, length) |
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@staticmethod |
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def count_flops(model, _x, y): |
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return count_flops_attn(model, _x, y) |
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class Timestep(nn.Module): |
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def __init__(self, dim): |
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super().__init__() |
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@ -507,6 +319,7 @@ class UNetModel(nn.Module):
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device=None, |
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): |
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super().__init__() |
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assert use_spatial_transformer == True, "use_spatial_transformer has to be true" |
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if use_spatial_transformer: |
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assert context_dim is not None, 'Fool!! You forgot to include the dimension of your cross-attention conditioning...' |
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@ -631,14 +444,7 @@ class UNetModel(nn.Module):
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disabled_sa = False |
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if not exists(num_attention_blocks) or nr < num_attention_blocks[level]: |
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layers.append( |
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AttentionBlock( |
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ch, |
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use_checkpoint=use_checkpoint, |
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num_heads=num_heads, |
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num_head_channels=dim_head, |
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use_new_attention_order=use_new_attention_order, |
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) if not use_spatial_transformer else SpatialTransformer( |
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layers.append(SpatialTransformer( |
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ch, num_heads, dim_head, depth=transformer_depth[level], context_dim=context_dim, |
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disable_self_attn=disabled_sa, use_linear=use_linear_in_transformer, |
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use_checkpoint=use_checkpoint, dtype=self.dtype, device=device |
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@ -693,13 +499,7 @@ class UNetModel(nn.Module):
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dtype=self.dtype, |
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device=device, |
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), |
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AttentionBlock( |
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ch, |
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use_checkpoint=use_checkpoint, |
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num_heads=num_heads, |
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num_head_channels=dim_head, |
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use_new_attention_order=use_new_attention_order, |
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) if not use_spatial_transformer else SpatialTransformer( # always uses a self-attn |
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SpatialTransformer( # always uses a self-attn |
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ch, num_heads, dim_head, depth=transformer_depth_middle, context_dim=context_dim, |
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disable_self_attn=disable_middle_self_attn, use_linear=use_linear_in_transformer, |
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use_checkpoint=use_checkpoint, dtype=self.dtype, device=device |
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@ -751,13 +551,7 @@ class UNetModel(nn.Module):
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if not exists(num_attention_blocks) or i < num_attention_blocks[level]: |
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layers.append( |
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AttentionBlock( |
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ch, |
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use_checkpoint=use_checkpoint, |
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num_heads=num_heads_upsample, |
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num_head_channels=dim_head, |
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use_new_attention_order=use_new_attention_order, |
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) if not use_spatial_transformer else SpatialTransformer( |
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SpatialTransformer( |
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ch, num_heads, dim_head, depth=transformer_depth[level], context_dim=context_dim, |
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disable_self_attn=disabled_sa, use_linear=use_linear_in_transformer, |
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use_checkpoint=use_checkpoint, dtype=self.dtype, device=device |
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@ -797,22 +591,6 @@ class UNetModel(nn.Module):
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#nn.LogSoftmax(dim=1) # change to cross_entropy and produce non-normalized logits |
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) |
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def convert_to_fp16(self): |
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""" |
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Convert the torso of the model to float16. |
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""" |
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self.input_blocks.apply(convert_module_to_f16) |
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self.middle_block.apply(convert_module_to_f16) |
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self.output_blocks.apply(convert_module_to_f16) |
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def convert_to_fp32(self): |
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""" |
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Convert the torso of the model to float32. |
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""" |
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self.input_blocks.apply(convert_module_to_f32) |
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self.middle_block.apply(convert_module_to_f32) |
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self.output_blocks.apply(convert_module_to_f32) |
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def forward(self, x, timesteps=None, context=None, y=None, control=None, transformer_options={}, **kwargs): |
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""" |
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Apply the model to an input batch. |
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