Why use evaluation results of train data when train biencoder?

[scarlettllc]

        logger.info("Valid data evaluation")
        results = evaluate(
            reranker, valid_dataloader, params,
            cand_encs=cand_encs, device=device,
            logger=logger, faiss_index=cand_encs_index,
            get_losses=params["get_losses"],
        )
        logger.info("Train data evaluation")
        results = evaluate(
            reranker, train_dataloader, params,
            cand_encs=cand_encs, device=device,
            logger=logger, faiss_index=cand_encs_index,
            get_losses=params["get_losses"],
        )

        ls = [best_score, results["normalized_f1"]]
        li = [best_epoch_idx, epoch_idx]