    def aggregate_logging_outputs(logging_outputs):
        """Aggregate logging outputs from data parallel training."""
        loss_sum = sum(log.get("loss", 0) for log in logging_outputs)
        symm_kl_sum = sum(log.get("symm_kl", 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)

        agg_output = {
            "loss": loss_sum / sample_size / math.log(2),
            "symm_kl": symm_kl_sum / sample_size,
            "ntokens": ntokens,
            "nsentences": nsentences,
            "sample_size": sample_size,
        }

        if len(logging_outputs) > 0 and "ncorrect" in logging_outputs[0]:
            ncorrect = sum(log.get("ncorrect", 0) for log in logging_outputs)
            agg_output.update(accuracy=ncorrect / nsentences)

        if sample_size != ntokens:
            agg_output["nll_loss"] = loss_sum / ntokens / math.log(2)
        return agg_output
Aggregate logging outputs from data parallel training.
examples/rxf/rxf_src/sentence_prediction_r3f.py