[s2s] rougeLSum expects \n between sentences (#7410)

Co-authored-by: Swetha Mandava <smandava@nvidia.com>

examples/seq2seq/utils.py

@@ -18,6 +18,7 @@ from sacrebleu import corpus_bleu
 from torch import nn
 from torch.utils.data import Dataset, Sampler
 
+from sentence_splitter import add_newline_to_end_of_each_sentence
 from transformers import BartTokenizer
 from transformers.file_utils import cached_property
 
@@ -378,19 +379,63 @@ def get_git_info():
     return repo_infos
 
 
-ROUGE_KEYS = ["rouge1", "rouge2", "rougeL"]
+ROUGE_KEYS = ["rouge1", "rouge2", "rougeL", "rougeLsum"]
 
 
-def calculate_rouge(output_lns: List[str], reference_lns: List[str], use_stemmer=True) -> Dict:
-    scorer = rouge_scorer.RougeScorer(ROUGE_KEYS, use_stemmer=use_stemmer)
+def extract_rouge_mid_statistics(dct):
+    new_dict = {}
+    for k1, v1 in dct.items():
+        mid = v1.mid
+        new_dict[k1] = {stat: round(getattr(mid, stat), 4) for stat in ["precision", "recall", "fmeasure"]}
+    return new_dict
+
+
+def calculate_rouge(
+    pred_lns: List[str],
+    tgt_lns: List[str],
+    use_stemmer=True,
+    rouge_keys=ROUGE_KEYS,
+    return_precision_and_recall=False,
+    bootstrap_aggregation=True,
+    newline_sep=True,
+) -> Dict:
+    """Calculate rouge using rouge_scorer package.
+
+    Args:
+        pred_lns: list of summaries generated by model
+        tgt_lns: list of groundtruth summaries (e.g. contents of val.target)
+        use_stemmer:  Bool indicating whether Porter stemmer should be used to
+        strip word suffixes to improve matching.
+        rouge_keys:  which metrics to compute, defaults to rouge1, rouge2, rougeL, rougeLsum
+        return_precision_and_recall: (False) whether to also return precision and recall.
+        bootstrap_aggregation: whether to do the typical bootstrap resampling of scores. Defaults to True, if False
+            this function returns a collections.defaultdict[metric: list of values for each observation for each subscore]``
+        newline_sep:(default=True) whether to add newline between sentences. This is essential for calculation rougeL
+        on multi sentence summaries (CNN/DM dataset).
+
+    Returns:
+         Dict[score: value] if aggregate else defaultdict(list) keyed by rouge_keys
+
+    """
+    scorer = rouge_scorer.RougeScorer(rouge_keys, use_stemmer=use_stemmer)
     aggregator = scoring.BootstrapAggregator()
-
-    for reference_ln, output_ln in zip(reference_lns, output_lns):
-        scores = scorer.score(reference_ln, output_ln)
+    for pred, tgt in zip(tgt_lns, pred_lns):
+        # rougeLsum expects "\n" separated sentences within a summary
+        if newline_sep:
+            pred = add_newline_to_end_of_each_sentence(pred)
+            tgt = add_newline_to_end_of_each_sentence(tgt)
+        scores = scorer.score(pred, tgt)
         aggregator.add_scores(scores)
 
-    result = aggregator.aggregate()
-    return {k: round(v.mid.fmeasure * 100, 4) for k, v in result.items()}
+    if bootstrap_aggregation:
+        result = aggregator.aggregate()
+        if return_precision_and_recall:
+            return extract_rouge_mid_statistics(result)  # here we return dict
+        else:
+            return {k: round(v.mid.fmeasure * 100, 4) for k, v in result.items()}
+
+    else:
+        return aggregator._scores  # here we return defaultdict(list)
 
 
 # Utilities for freezing parameters and checking whether they are frozen
@@ -423,9 +468,6 @@ def assert_not_all_frozen(model):
     assert any(model_grads), f"none of {npars} weights require grad"
 
 
-# CLI Parsing utils
-
-
 def parse_numeric_n_bool_cl_kwargs(unparsed_args: List[str]) -> Dict[str, Union[int, float, bool]]:
     """
     Parse an argv list of unspecified command line args to a dict.