Fix decoding score comparison when using logits processors or warpers (#10638)

* Normalize using a logits warper

* Add a flag in `generate` to support the logit renormalization

* Add in RAG

tests/generation/test_generation_logits_process.py

@@ -33,6 +33,7 @@ if is_torch_available():
         ForcedEOSTokenLogitsProcessor,
         HammingDiversityLogitsProcessor,
         InfNanRemoveLogitsProcessor,
+        LogitNormalization,
         LogitsProcessorList,
         MinLengthLogitsProcessor,
         NoBadWordsLogitsProcessor,
@@ -537,3 +538,18 @@ class LogitsProcessorTest(unittest.TestCase):
                 scores_after_start[penalty_start + 1 :, eos_token_id], scores[penalty_start + 1 :, eos_token_id]
             ).all()
         )
+
+    def test_normalization(self):
+        input_ids = None
+
+        scores = torch.tensor(
+            [[-23.18, -29.96, -43.54, 47.77], [-33.58, -26.87, -32.96, 22.51]], device=torch_device, dtype=torch.float
+        )
+
+        logit_normalization = LogitNormalization()
+        normalized_scores = logit_normalization(input_ids, scores).exp()
+
+        ones = torch.ones(scores.shape[0], device=torch_device, dtype=torch.float)
+        self.assertTrue(normalized_scores.sum(dim=-1).allclose(ones))
+
+        self.assertTrue(normalized_scores.allclose(scores.softmax(dim=-1)))