Generate: `min_tokens_to_keep` has to be `>= 1` (#24453)

src/transformers/generation/flax_logits_process.py

@@ -129,8 +129,8 @@ class FlaxTopPLogitsWarper(FlaxLogitsWarper):
     def __init__(self, top_p: float, filter_value: float = -float("Inf"), min_tokens_to_keep: int = 1):
         if not isinstance(top_p, float) or (top_p < 0 or top_p > 1.0):
             raise ValueError(f"`top_p` has to be a float > 0 and < 1, but is {top_p}")
-        if not isinstance(min_tokens_to_keep, int) or (min_tokens_to_keep < 0):
-            raise ValueError(f"`min_tokens_to_keep` has to be a non-negative integer, but is {min_tokens_to_keep}")
+        if not isinstance(min_tokens_to_keep, int) or (min_tokens_to_keep < 1):
+            raise ValueError(f"`min_tokens_to_keep` has to be a positive integer, but is {min_tokens_to_keep}")
 
         self.top_p = top_p
         self.filter_value = filter_value

src/transformers/generation/logits_process.py

@@ -255,8 +255,8 @@ class TopPLogitsWarper(LogitsWarper):
         top_p = float(top_p)
         if top_p < 0 or top_p > 1.0:
             raise ValueError(f"`top_p` has to be a float > 0 and < 1, but is {top_p}")
-        if not isinstance(min_tokens_to_keep, int) or (min_tokens_to_keep < 0):
-            raise ValueError(f"`min_tokens_to_keep` has to be a non-negative integer, but is {min_tokens_to_keep}")
+        if not isinstance(min_tokens_to_keep, int) or (min_tokens_to_keep < 1):
+            raise ValueError(f"`min_tokens_to_keep` has to be a positive integer, but is {min_tokens_to_keep}")
 
         self.top_p = top_p
         self.filter_value = filter_value
@@ -323,6 +323,8 @@ class TypicalLogitsWarper(LogitsWarper):
         mass = float(mass)
         if not (mass > 0 and mass < 1):
             raise ValueError(f"`typical_p` has to be a float > 0 and < 1, but is {mass}")
+        if not isinstance(min_tokens_to_keep, int) or (min_tokens_to_keep < 1):
+            raise ValueError(f"`min_tokens_to_keep` has to be a positive integer, but is {min_tokens_to_keep}")
 
         self.filter_value = filter_value
         self.mass = mass
@@ -344,9 +346,7 @@ class TypicalLogitsWarper(LogitsWarper):
         last_ind = (cumulative_probs < self.mass).sum(dim=1)
         last_ind[last_ind < 0] = 0
         sorted_indices_to_remove = sorted_scores > sorted_scores.gather(1, last_ind.view(-1, 1))
-        if self.min_tokens_to_keep > 1:
-            # Keep at least min_tokens_to_keep (set to min_tokens_to_keep-1 because we add the first one below)
-            sorted_indices_to_remove[..., : self.min_tokens_to_keep] = 0
+        sorted_indices_to_remove[..., : self.min_tokens_to_keep] = 0
         indices_to_remove = sorted_indices_to_remove.scatter(1, sorted_indices, sorted_indices_to_remove)
 
         scores = scores.masked_fill(indices_to_remove, self.filter_value)

src/transformers/generation/tf_logits_process.py

@@ -160,8 +160,8 @@ class TFTopPLogitsWarper(TFLogitsWarper):
     def __init__(self, top_p: float, filter_value: float = -float("Inf"), min_tokens_to_keep: int = 1):
         if not isinstance(top_p, float) or (top_p < 0 or top_p > 1.0):
             raise ValueError(f"`top_p` has to be a float > 0 and < 1, but is {top_p}")
-        if not isinstance(min_tokens_to_keep, int) or (min_tokens_to_keep < 0):
-            raise ValueError(f"`min_tokens_to_keep` has to be a non-negative integer, but is {min_tokens_to_keep}")
+        if not isinstance(min_tokens_to_keep, int) or (min_tokens_to_keep < 1):
+            raise ValueError(f"`min_tokens_to_keep` has to be a positive integer, but is {min_tokens_to_keep}")
 
         self.top_p = top_p
         self.filter_value = filter_value