def _generate_score()

in pytorch_translate/generate.py [0:0]


def _generate_score(models, args, task, dataset, modify_target_dict):
    use_cuda = torch.cuda.is_available() and not args.cpu

    # Load ensemble
    if not args.quiet:
        print(
            "| loading model(s) from {}".format(
                ", ".join(args.path.split(CHECKPOINT_PATHS_DELIMITER))
            )
        )

    # Optimize ensemble for generation
    for model in models:
        model.make_generation_fast_(
            beamable_mm_beam_size=None if args.no_beamable_mm else args.beam,
            need_attn=True,
        )

    translator = build_sequence_generator(args, task, models)
    # Load alignment dictionary for unknown word replacement
    # (None if no unknown word replacement, empty if no path to align dictionary)
    align_dict = utils.load_align_dict(args.replace_unk)

    print("seed number is" + str(args.max_examples_to_evaluate_seed))
    if args.max_examples_to_evaluate > 0:
        pytorch_translate_data.subsample_pair_dataset(
            dataset, args.max_examples_to_evaluate, args.max_examples_to_evaluate_seed
        )

    # Keep track of translations
    # Initialize with empty translations
    # and zero probs scores
    translated_sentences = [""] * len(dataset)
    translated_scores = [0.0] * len(dataset)
    hypos_list = []

    collect_output_hypos = getattr(args, "output_hypos_binary_path", False)
    if collect_output_hypos:
        output_hypos_token_arrays = [None] * len(dataset)

    # Generate and compute BLEU score
    dst_dict = task.target_dictionary
    if args.sacrebleu:
        scorer = bleu.SacrebleuScorer(bleu.SacrebleuConfig())
    else:
        scorer = bleu.Scorer(
            bleu.BleuConfig(
                pad=dst_dict.pad(),
                eos=dst_dict.eos(),
                unk=dst_dict.unk(),
            )
        )

    itr = task.get_batch_iterator(
        dataset=dataset,
        max_tokens=args.max_tokens,
        max_sentences=args.batch_size,
        max_positions=utils.resolve_max_positions(
            task.max_positions(), *[model.max_positions() for model in models]
        ),
        ignore_invalid_inputs=args.skip_invalid_size_inputs_valid_test,
        required_batch_size_multiple=8,
        num_shards=args.num_shards,
        shard_id=args.shard_id,
        num_workers=args.num_workers,
    ).next_epoch_itr(shuffle=False)

    oracle_scorer = None
    if args.report_oracle_bleu:
        oracle_scorer = bleu.Scorer(
            bleu.BleuConfig(
                pad=dst_dict.pad(),
                eos=dst_dict.eos(),
                unk=dst_dict.unk(),
            )
        )

    rescorer = None
    num_sentences = 0
    translation_samples = []
    translation_info_list = []
    with progress_bar.build_progress_bar(args, itr) as t:
        wps_meter = TimeMeter()
        gen_timer = StopwatchMeter()
        translations = translator.generate_batched_itr(
            t,
            maxlen_a=args.max_len_a,
            maxlen_b=args.max_len_b,
            cuda=use_cuda,
            timer=gen_timer,
            prefix_size=1
            if pytorch_translate_data.is_multilingual_many_to_one(args)
            else 0,
        )

        for trans_info in _iter_translations(
            args, task, dataset, translations, align_dict, rescorer, modify_target_dict
        ):
            if hasattr(scorer, "add_string"):
                scorer.add_string(trans_info.target_str, trans_info.hypo_str)
            else:
                scorer.add(trans_info.target_tokens, trans_info.hypo_tokens)
            if oracle_scorer is not None:
                oracle_scorer.add(trans_info.target_tokens, trans_info.best_hypo_tokens)

            if getattr(args, "translation_output_file", False):
                translated_sentences[trans_info.sample_id] = trans_info.hypo_str
            if getattr(args, "translation_probs_file", False):
                translated_scores[trans_info.sample_id] = trans_info.hypo_score
            if getattr(args, "hypotheses_export_path", False):
                hypos_list.append(trans_info.hypos)
            if collect_output_hypos:
                output_hypos_token_arrays[
                    trans_info.sample_id
                ] = trans_info.best_hypo_tokens
            if args.translation_info_export_path is not None:
                # Strip expensive data from hypotheses before saving
                hypos = [
                    {k: v for k, v in hypo.items() if k in ["tokens", "score"]}
                    for hypo in trans_info.hypos
                ]
                # Make sure everything is on cpu before exporting
                hypos = [
                    {"score": hypo["score"], "tokens": hypo["tokens"].cpu()}
                    for hypo in hypos
                ]
                translation_info_list.append(
                    {
                        "src_tokens": trans_info.src_tokens.cpu(),
                        "target_tokens": trans_info.target_tokens,
                        "hypos": hypos,
                    }
                )
            translation_samples.append(
                collections.OrderedDict(
                    {
                        "sample_id": trans_info.sample_id.item(),
                        "src_str": trans_info.src_str,
                        "target_str": trans_info.target_str,
                        "hypo_str": trans_info.hypo_str,
                    }
                )
            )
            wps_meter.update(trans_info.src_tokens.size(0))
            t.log({"wps": round(wps_meter.avg)})
            num_sentences += 1

    # If applicable, save collected hypothesis tokens to binary output file
    if collect_output_hypos:
        output_dataset = pytorch_translate_data.InMemoryIndexedDataset()
        output_dataset.load_from_sequences(output_hypos_token_arrays)
        output_dataset.save(args.output_hypos_binary_path)
    if args.output_source_binary_path:
        dataset.src.save(args.output_source_binary_path)
    if args.translation_info_export_path is not None:
        f = open(args.translation_info_export_path, "wb")
        pickle.dump(translation_info_list, f)
        f.close()

    # If applicable, save the translations and scores to the output files
    # These two ouputs are used in dual learning for weighted backtranslation
    if getattr(args, "translation_output_file", False) and getattr(
        args, "translation_probs_file", False
    ):
        with open(args.translation_output_file, "w") as translation_file, open(
            args.translation_probs_file, "w"
        ) as score_file:
            for hypo_str, hypo_score in zip(translated_sentences, translated_scores):
                if len(hypo_str.strip()) > 0:
                    print(hypo_str, file=translation_file)
                    print(np.exp(hypo_score), file=score_file)

    # For eg. external evaluation
    if getattr(args, "hypotheses_export_path", False):
        with open(args.hypotheses_export_path, "w") as out_file:
            for hypos in hypos_list:
                for hypo in hypos:
                    print(
                        task.tgt_dict.string(
                            hypo["tokens"], bpe_symbol=args.post_process
                        ),
                        file=out_file,
                    )

    if oracle_scorer is not None:
        print(f"| Oracle BLEU (best hypo in beam): {oracle_scorer.result_string()}")

    return scorer, num_sentences, gen_timer, translation_samples