blip_model.py

import torch
import numpy as np
import openvino as ov
from typing import List, Dict
from transformers.modeling_outputs import CausalLMOutputWithCrossAttentions


def init_past_inputs(model_inputs:List):
    """
    Helper function for initialization of past inputs on first inference step
    Parameters:
      model_inputs (List): list of model inputs
    Returns:
      pkv (List[ov.Tensor]): list of filled past key values
    """
    pkv = []
    for input_tensor in model_inputs[4:]:
        partial_shape = input_tensor.partial_shape
        partial_shape[0] = 1
        partial_shape[2] = 0
        pkv.append(ov.Tensor(ov.Type.f32, partial_shape.get_shape()))
    return pkv


def postprocess_text_decoder_outputs(output:Dict):
    """
    Helper function for rearranging model outputs and wrapping to CausalLMOutputWithCrossAttentions
    Parameters:
      output (Dict): dictionary with model output
    Returns
      wrapped_outputs (CausalLMOutputWithCrossAttentions): outputs wrapped to CausalLMOutputWithCrossAttentions format
    """
    logits = torch.from_numpy(output[0])
    past_kv = list(output.values())[1:]
    return CausalLMOutputWithCrossAttentions(
        loss=None,
        logits=logits,
        past_key_values=past_kv,
        hidden_states=None,
        attentions=None,
        cross_attentions=None
    )


def text_decoder_forward(
        ov_text_decoder_with_past:ov.CompiledModel,
        input_ids:torch.Tensor,
        attention_mask:torch.Tensor,
        past_key_values:List[ov.Tensor],
        encoder_hidden_states:torch.Tensor,
        encoder_attention_mask:torch.Tensor,
        **kwargs
    ):
    """
    Inference function for text_decoder in one generation step
    Parameters:
      input_ids (torch.Tensor): input token ids
      attention_mask (torch.Tensor): attention mask for input token ids
      past_key_values (List[ov.Tensor] list of cached decoder hidden states from previous step
      encoder_hidden_states (torch.Tensor): encoder (vision or text) hidden states
      encoder_attention_mask (torch.Tensor): attnetion mask for encoder hidden states
    Returns
      model outputs (CausalLMOutputWithCrossAttentions): model prediction wrapped to CausalLMOutputWithCrossAttentions class including predicted logits and hidden states for caching
    """
    inputs = [input_ids, attention_mask, encoder_hidden_states, encoder_attention_mask]
    if past_key_values is None:
        inputs.extend(init_past_inputs(ov_text_decoder_with_past.inputs))
    else:
        inputs.extend(past_key_values)
    outputs = ov_text_decoder_with_past(inputs)
    return postprocess_text_decoder_outputs(outputs)


class OVBlipModel:
    """
    Model class for inference BLIP model with OpenVINO
    """
    def __init__(self, config, decoder_start_token_id:int, vision_model, text_encoder, text_decoder):
        """
        Initialization class parameters
        """
        self.vision_model = vision_model
        self.vision_model_out = vision_model.output(0)
        self.text_encoder = text_encoder
        self.text_encoder_out = text_encoder.output(0)
        self.text_decoder = text_decoder
        self.config = config
        self.decoder_start_token_id = decoder_start_token_id
        self.decoder_input_ids = config.text_config.bos_token_id

    def generate_answer(self, pixel_values:torch.Tensor, input_ids:torch.Tensor, attention_mask:torch.Tensor, **generate_kwargs):
        """
        Visual Question Answering prediction
        Parameters:
          pixel_values (torch.Tensor): preprocessed image pixel values
          input_ids (torch.Tensor): question token ids after tokenization
          attention_mask (torch.Tensor): attention mask for question tokens
        Retruns:
          generation output (torch.Tensor): tensor which represents sequence of generated answer token ids
        """
        image_embed = self.vision_model(pixel_values.detach().numpy())[self.vision_model_out]
        image_attention_mask = np.ones(image_embed.shape[:-1], dtype=int)
        if isinstance(input_ids, list):
            input_ids = torch.LongTensor(input_ids)
        question_embeds = self.text_encoder([input_ids.detach().numpy(), attention_mask.detach().numpy(), image_embed, image_attention_mask])[self.text_encoder_out]
        question_attention_mask = np.ones(question_embeds.shape[:-1], dtype=int)

        bos_ids = np.full((question_embeds.shape[0], 1), fill_value=self.decoder_start_token_id)

        outputs = self.text_decoder.generate(
            input_ids=torch.from_numpy(bos_ids),
            eos_token_id=self.config.text_config.sep_token_id,
            pad_token_id=self.config.text_config.pad_token_id,
            encoder_hidden_states=torch.from_numpy(question_embeds),
            encoder_attention_mask=torch.from_numpy(question_attention_mask),
            **generate_kwargs,
        )
        return outputs

    def generate_caption(self, pixel_values:torch.Tensor, input_ids:torch.Tensor = None, attention_mask:torch.Tensor = None, **generate_kwargs):
        """
        Image Captioning prediction
        Parameters:
          pixel_values (torch.Tensor): preprocessed image pixel values
          input_ids (torch.Tensor, *optional*, None): pregenerated caption token ids after tokenization, if provided caption generation continue provided text
          attention_mask (torch.Tensor): attention mask for caption tokens, used only if input_ids provided
        Retruns:
          generation output (torch.Tensor): tensor which represents sequence of generated caption token ids
        """
        batch_size = pixel_values.shape[0]

        image_embeds = self.vision_model(pixel_values.detach().numpy())[self.vision_model_out]

        image_attention_mask = torch.ones(image_embeds.shape[:-1], dtype=torch.long)

        if isinstance(input_ids, list):
            input_ids = torch.LongTensor(input_ids)
        elif input_ids is None:
            input_ids = (
                torch.LongTensor([[self.config.text_config.bos_token_id, self.config.text_config.eos_token_id]])
                .repeat(batch_size, 1)
            )
        input_ids[:, 0] = self.config.text_config.bos_token_id
        attention_mask = attention_mask[:, :-1] if attention_mask is not None else None

        outputs = self.text_decoder.generate(
            input_ids=input_ids[:, :-1],
            eos_token_id=self.config.text_config.sep_token_id,
            pad_token_id=self.config.text_config.pad_token_id,
            attention_mask=attention_mask,
            encoder_hidden_states=torch.from_numpy(image_embeds),
            encoder_attention_mask=image_attention_mask,
            **generate_kwargs,
        )

        return outputs