criterions/refcoco_scst_loss.py

# Modified from OFA code.
# Copyright 2022 The OFA-Sys Team. 
# All rights reserved.
# This source code is licensed under the Apache 2.0 license 
# found in the LICENSE file in the root directory.

import math
import string
from dataclasses import dataclass, field
from collections import OrderedDict
from typing import Optional

import torch
from fairseq import metrics, utils
from fairseq.criterions import FairseqCriterion, register_criterion
from fairseq.dataclass import FairseqDataclass
from omegaconf import II

from data import data_utils
from utils.cider.pyciderevalcap.ciderD.ciderD import CiderD



def scst_loss(lprobs, target, reward, ignore_index=None, reduce=True, ce=False):

    if ce:
        loss = -lprobs.gather(dim=-1, index=target.unsqueeze(-1)).squeeze(-1)
    elif isinstance(reward, float):
        loss = -lprobs.gather(dim=-1, index=target.unsqueeze(-1)).squeeze() * reward
    else:
        loss = -lprobs.gather(dim=-1, index=target.unsqueeze(-1)).squeeze() * reward.unsqueeze(-1)

    if ignore_index is not None:
        pad_mask = target.eq(ignore_index)
        loss.masked_fill_(pad_mask, 0.0)
        ntokens = (~pad_mask).sum()
    else:
        loss = loss.squeeze(-1)
        ntokens = target.numel()
    if reduce:
        loss = loss.sum()
    return loss, ntokens


@dataclass
class RefCOCOScstRewardCriterionConfig(FairseqDataclass):
    scst_cider_cached_tokens: Optional[str] = field(
        default="coco-train-words.p",
        metadata={"help": "path to cached cPickle file used to calculate CIDEr scores"},
    )
    ignore_prefix_size: int = field(
        default=0,
        metadata={"help": "Ignore first N tokens"},
    )
    sentence_avg: bool = II("optimization.sentence_avg")
    constraint_range: Optional[str] = field(
        default=None,
        metadata={"help": "constraint range"}
    )


    acc_thresh: Optional[float] = field(
        default=None, metadata={"help": "acc thresh for refcoco"}
    )
    metric: Optional[str] = field(
        default='acc',
        metadata={"help": "metric"}
    )

    max_area_size: Optional[float] = field(
        default=None, metadata={"help": "max_area_size"}
    )

    min_area_size: Optional[float] = field(
        default=None, metadata={"help": "min_area_size"}
    )
    logprob: Optional[bool] = field(
        default=False, metadata={"help": "maximise log prob"}
    )

    pos_reward: Optional[float] = field(
        default=None, metadata={"help": "pos_reward"}
    )

    neg_reward: Optional[float] = field(
        default=None, metadata={"help": "neg_reward"}
    )

    reinforce: Optional[bool] = field(
        default=False, metadata={"help": "reinforce"}
    )

    lambda_reinforce: Optional[float] = field(
        default=0, metadata={"help": "lambda_reinforce"}
    )

    medium_area: Optional[bool] = field(
        default=False, metadata={"help": "reinforce"}
    )

@register_criterion(
    "refcoco_scst_reward_criterion", dataclass=RefCOCOScstRewardCriterionConfig
)
class RefCOCOScstRewardCriterion(FairseqCriterion):
    CIDER_REWARD_WEIGHT = 1

    def __init__(
        self,
        task,
        scst_cider_cached_tokens,
        sentence_avg,
        ignore_prefix_size=0,
        constraint_range=None,
        acc_thresh=None,
        metric='acc',
        max_area_size=None,
        min_area_size=None,
        logprob=False,
        pos_reward=None,
        neg_reward=None,
        reinforce=False,
        lambda_reinforce=0,
        medium_area=False,
    ):
        super().__init__(task)
        self.sentence_avg = sentence_avg
        self.ignore_prefix_size = ignore_prefix_size
        self.transtab = str.maketrans({key: None for key in string.punctuation})

        self.constraint_start = None
        self.constraint_end = None
        if constraint_range is not None:
            constraint_start, constraint_end = constraint_range.split(',')
            self.constraint_start = int(constraint_start)
            self.constraint_end = int(constraint_end)

        self.metric = metric 
        print("metric", metric)

        self.acc_thresh = acc_thresh
        self.metric = metric
        self.min_area_size = min_area_size
        self.max_area_size = max_area_size
        self.logprob = logprob

        self.pos_reward = pos_reward
        self.neg_reward = neg_reward

        self.reinforce = reinforce
        self.lambda_reinforce = lambda_reinforce

        self.medium_area = medium_area


            

    def forward(self, model, sample, update_num=0, reduce=True):
        """Compute the loss for the given sample.

        Returns a tuple with three elements:
        1) the loss
        2) the sample size, which is used as the denominator for the gradient
        3) logging outputs to display while training
        """
        loss, score, ntokens, nsentences = self.compute_loss(model, sample, reduce=reduce)

        sample_size = (
            nsentences if self.sentence_avg else ntokens
        )
        logging_output = {
            "loss": loss.data,
            "score": score,
            "ntokens": ntokens,
            "nsentences": nsentences,
            "sample_size": sample_size,
        }
        return loss, sample_size, logging_output

    def _calculate_eval_scores(self, gen_res, gt_idx, gt_res):
        '''
        gen_res: generated captions, list of str
        gt_idx: list of int, of the same length as gen_res
        gt_res: ground truth captions, list of list of str.
            gen_res[i] corresponds to gt_res[gt_idx[i]]
            Each image can have multiple ground truth captions
        '''

        gen_res_size = len(gen_res)

        res = OrderedDict()
        for i in range(gen_res_size):
            res[i] = [self._wrap_sentence(gen_res[i].strip().translate(self.transtab))]

        gts = OrderedDict()
        gt_res_ = [
            [self._wrap_sentence(gt_res[i][j].strip().translate(self.transtab)) for j in range(len(gt_res[i]))]
                for i in range(len(gt_res))
        ]
        for i in range(gen_res_size):
            gts[i] = gt_res_[gt_idx[i]]

        res_ = [{'image_id':i, 'caption': res[i]} for i in range(len(res))]

        # replace with other metrics
        if self.metric != 'cider':
            predicts = [res[i][0] if isinstance(res[i], list) else res[i] for i in range(len(res))]

            answers = [gts[i] for i in range(gen_res_size)]
            
            results = self.evaluator.run_evaluation(predicts, answers)
            batch_cider_scores = results[self.metric]

            batch_cider_scores = torch.tensor(batch_cider_scores).repeat(gen_res_size)
        else:
            _, batch_cider_scores = self.scst_cider_scorer.compute_score(gts, res_)

        scores = self.CIDER_REWARD_WEIGHT * batch_cider_scores
        return scores

    @classmethod
    def _wrap_sentence(self, s):
        # ensure the sentence ends with <eos> token
        # in order to keep consisitent with cider_cached_tokens
        r = s.strip()
        if r.endswith('.'):
            r = r[:-1]
        r += ' <eos>'
        return r


    def get_generator_out(self, model, sample):


        model.eval()
        with torch.no_grad():
            self.task.scst_generator.model.eval()
            gen_out = self.task.scst_generator.generate([model], sample)

        gen_target = []
        gen_res = []
        gt_res = []
        for i in range(len(gen_out)):
            gen_res.append(gen_out[i][0]["tokens"][:-1] - len(self.task.src_dict) + self.task.cfg.num_bins)
            gt_res.append(sample["target"][i][:-1] - len(self.task.src_dict) + self.task.cfg.num_bins)
            gen_target.append(gen_out[i][0]["tokens"][:-1].int().cpu())

        return gen_target, gen_res, gt_res

    def _calculate_ap_score(self, hyps, refs, thresh=0.5, min_area_size=None, max_area_size=None, medium_area=False):
        interacts = torch.cat(
            [torch.where(hyps[:, :2] < refs[:, :2], refs[:, :2], hyps[:, :2]),
             torch.where(hyps[:, 2:] < refs[:, 2:], hyps[:, 2:], refs[:, 2:])],
            dim=1
        )
        area_predictions = (hyps[:, 2] - hyps[:, 0]) * (hyps[:, 3] - hyps[:, 1]) ## x1, y1, x2, y2, x1 < x2
        area_targets = (refs[:, 2] - refs[:, 0]) * (refs[:, 3] - refs[:, 1])
        interacts_w = interacts[:, 2] - interacts[:, 0]
        interacts_h = interacts[:, 3] - interacts[:, 1]
        area_interacts = interacts_w * interacts_h
        ious = area_interacts / (area_predictions + area_targets - area_interacts + 1e-6)
        

        if max_area_size is not None and min_area_size is not None:
            if medium_area:
                ious =  ious * (torch.logical_and(area_targets > max_area_size, area_targets < min_area_size).float())

            else:
                ious =  ious * (torch.logical_or(area_targets < max_area_size, area_targets > min_area_size).float())

        elif min_area_size is not None:
            if medium_area:
                ious =  ious * (area_targets < min_area_size).float() # as max areas
            else:
                ious =  ious * (area_targets > min_area_size).float()

        elif max_area_size is not None:
            if medium_area:
                ious =  ious * (area_targets > max_area_size).float()
            else:
                ious =  ious * (area_targets < max_area_size).float()

        if thresh is None:
            return ious
        else:
            return ((ious >= thresh) & (interacts_w > 0) & (interacts_h > 0)).float()


    def get_reward_and_scores(self, gen_res, gt_res, device, sample):
        

        hyps_, refs_ = torch.stack(gen_res, dim=0), torch.stack(gt_res, dim=0)

        hyps = hyps_ / (self.task.cfg.num_bins - 1) * self.task.cfg.max_image_size
        refs = refs_ / (self.task.cfg.num_bins - 1) * self.task.cfg.max_image_size
        
        hyps[:, ::2] /= sample['w_resize_ratios'].unsqueeze(1)
        hyps[:, 1::2] /= sample['h_resize_ratios'].unsqueeze(1)
        refs[:, ::2] /= sample['w_resize_ratios'].unsqueeze(1)
        refs[:, 1::2] /= sample['h_resize_ratios'].unsqueeze(1)

        if self.metric == 'acc':
            scores = self._calculate_ap_score(hyps, sample['region_coords'].float(), thresh=self.acc_thresh, 
                                              min_area_size=self.min_area_size, max_area_size=self.max_area_size, medium_area=self.medium_area)
        else:
            raise NotImplemented
        

        if self.pos_reward:
            scores = torch.where(scores > 0, self.pos_reward, scores)
        if self.neg_reward:
            scores = torch.where(scores == 0, self.neg_reward, scores)

        return scores, scores


    def get_net_output(self, model, sample, gen_target):
        def merge(sample_list, eos=self.task.tgt_dict.eos(), move_eos_to_beginning=False):
            return data_utils.collate_tokens(
                sample_list,
                pad_idx=self.padding_idx,
                eos_idx=eos,
                left_pad=False,
                move_eos_to_beginning=move_eos_to_beginning,
            )

        batch_size = len(sample["target"])
        gen_target_size = len(gen_target)
        seq_per_img = gen_target_size // batch_size

        model.train()
        sample_src_tokens = torch.repeat_interleave(
            sample['net_input']['src_tokens'], seq_per_img, dim=0
        )
        sample_src_lengths = torch.repeat_interleave(
            sample['net_input']['src_lengths'], seq_per_img, dim=0
        )
        sample_patch_images = torch.repeat_interleave(
            sample['net_input']['patch_images'], seq_per_img, dim=0
        )
        sample_patch_masks = torch.repeat_interleave(
            sample['net_input']['patch_masks'], seq_per_img, dim=0
        )
        gen_prev_output_tokens = torch.as_tensor(
            merge(gen_target, eos=self.task.tgt_dict.bos(), move_eos_to_beginning=True),
            device=sample["target"].device, dtype=torch.int64
        )
        gen_target_tokens = torch.as_tensor(
            merge(gen_target), device=sample["target"].device, dtype=torch.int64
        )

        net_output = model(
            src_tokens=sample_src_tokens, src_lengths=sample_src_lengths,
            patch_images=sample_patch_images, patch_masks=sample_patch_masks,
            prev_output_tokens=gen_prev_output_tokens
        )

        return net_output, gen_target_tokens

    def get_lprobs_and_target(self, model, net_output, gen_target):
        if self.constraint_start is not None and self.constraint_end is not None:
            net_output[0][:, :, 4:self.constraint_start] = -math.inf
            net_output[0][:, :, self.constraint_end:] = -math.inf
        lprobs = model.get_normalized_probs(net_output, log_probs=True)
        if self.ignore_prefix_size > 0:
            if getattr(lprobs, "batch_first", False):
                lprobs = lprobs[:, self.ignore_prefix_size :, :].contiguous()
                gen_target = gen_target[:, self.ignore_prefix_size :].contiguous()
            else:
                lprobs = lprobs[self.ignore_prefix_size :, :, :].contiguous()
                gen_target = gen_target[self.ignore_prefix_size :, :].contiguous()
        return lprobs, gen_target

    def compute_loss(self, model, sample, reduce=True):
        gen_target, gen_res, gt_res = self.get_generator_out(model, sample)
        reward, scores = self.get_reward_and_scores(gen_res, gt_res, device=sample["target"].device, sample=sample)

        net_output, gen_target_tokens = self.get_net_output(model, sample, gen_target)

        gen_lprobs, gen_target_tokens = self.get_lprobs_and_target(model, net_output, gen_target_tokens)
        loss, ntokens = scst_loss(gen_lprobs, gen_target_tokens, reward, ignore_index=self.padding_idx, reduce=reduce)
        nsentences = gen_target_tokens.size(0)

        if self.lambda_reinforce > 0:
            target = model.get_targets(sample, net_output)[:, :-1] # ignore eos token
            if self.ignore_prefix_size > 0:
                target = target[:, self.ignore_prefix_size :].contiguous()

            loss_ce, ntokens_ = scst_loss(gen_lprobs, target, reward=1, ignore_index=self.padding_idx, reduce=reduce, ce=True)
            
            loss = loss_ce + self.lambda_reinforce*loss

        return loss, scores.sum(), ntokens, nsentences

    @classmethod
    def reduce_metrics(cls, logging_outputs) -> None:
        """Aggregate logging outputs from data parallel training."""
        loss_sum = sum(log.get("loss", 0) for log in logging_outputs)
        score_sum = sum(log.get("score", 0) for log in logging_outputs)
        ntokens = sum(log.get("ntokens", 0) for log in logging_outputs)
        nsentences = sum(log.get("nsentences", 0) for log in logging_outputs)
        sample_size = sum(log.get("sample_size", 0) for log in logging_outputs)

        metrics.log_scalar(
            "loss", loss_sum / sample_size, sample_size, round=3
        )
        metrics.log_scalar(
            "score", score_sum / nsentences, nsentences, round=3
        )

        metrics.log_scalar(
            "ntokens", ntokens, 1, round=3
        )
        metrics.log_scalar(
            "nsentences", nsentences, 1, round=3
        )
        metrics.log_scalar(
            "sample_size", sample_size, 1, round=3
        )

    @staticmethod
    def logging_outputs_can_be_summed() -> bool:
        """
        Whether the logging outputs returned by `forward` can be summed
        across workers prior to calling `reduce_metrics`. Setting this
        to True will improves distributed training speed.
        """
        return True