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import torch |
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import torch.nn as nn |
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from transformers import PreTrainedModel, T5ForConditionalGeneration, T5Config, AutoTokenizer |
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from .configuration_emuru import EmuruConfig |
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from diffusers import AutoencoderKL |
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from einops.layers.torch import Rearrange |
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from einops import rearrange, repeat |
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class Emuru(PreTrainedModel): |
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config_class = EmuruConfig |
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def __init__(self, config): |
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super().__init__(config) |
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self.tokenizer = AutoTokenizer.from_pretrained(config.tokenizer_config) |
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t5_config = T5Config.from_pretrained(config.t5_config) |
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t5_config.vocab_size = len(self.tokenizer) |
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self.T5 = T5ForConditionalGeneration(t5_config) |
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self.T5.lm_head = nn.Identity() |
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self.sos = nn.Embedding(1, t5_config.d_model) |
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vae_latent_size = 8 * config.vae_channels * config.slices_per_query |
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self.vae_to_t5 = nn.Linear(vae_latent_size, t5_config.d_model) |
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self.t5_to_vae = nn.Linear(t5_config.d_model, vae_latent_size, bias=False) |
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self.padding_token = nn.Parameter(torch.empty((1, vae_latent_size)), requires_grad=False) |
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self.padding_token_threshold = nn.Parameter(torch.empty(1), requires_grad=False) |
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self.vae = AutoencoderKL.from_pretrained(config.vae_config) |
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self.set_training(self.vae, False) |
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self.query_rearrange = Rearrange('b c h (w q) -> b w (q c h)', q=config.slices_per_query) |
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self.z_rearrange = Rearrange('b w (q c h) -> b c h (w q)', c=config.vae_channels, q=config.slices_per_query) |
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self.mse_criterion = nn.MSELoss() |
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self.init_weights() |
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def set_training(self, model, training): |
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model.train() if training else model.eval() |
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for param in model.parameters(): |
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param.requires_grad = training |
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def forward(self, img=None, input_ids=None, attention_mask=None, noise=0, **kwargs): |
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decoder_inputs_embeds, z_sequence, z = self._img_encode(img, noise) |
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output = self.T5(input_ids, attention_mask=attention_mask, decoder_inputs_embeds=decoder_inputs_embeds) |
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vae_latent = self.t5_to_vae(output.logits[:, :-1]) |
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pred_latent = self.z_rearrange(vae_latent) |
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mse_loss = self.mse_criterion(vae_latent, z_sequence) |
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return mse_loss, pred_latent, z |
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def generate(self, text=None, img=None, max_length=128, noise=0): |
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... |
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def _img_encode(self, img, noise=0): |
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posterior = self.vae.encode(img.float()) |
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z = posterior.latent_dist.sample() |
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z_sequence = self.query_rearrange(z) |
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noise_sequence = z_sequence |
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if noise > 0: |
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noise_sequence = z_sequence + torch.randn_like(z_sequence) * noise |
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decoder_inputs_embeds = self.query_emb(noise_sequence) |
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sos = repeat(self.sos.weight, '1 d -> b 1 d', b=decoder_inputs_embeds.size(0)) |
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decoder_inputs_embeds = torch.cat([sos, decoder_inputs_embeds], dim=1) |
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return decoder_inputs_embeds, z_sequence, z |
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def compute_padding_token(self): |
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... |
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def compute_padding_token_threshold(self): |
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... |
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