fix array generation stopping criteria

jsonformer/logits_processors.py

@@ -2,6 +2,7 @@
 from transformers import PreTrainedTokenizer, LogitsWarper, StoppingCriteria
 import torch
 
+
 class StringStoppingCriteria(StoppingCriteria):
     def __init__(self, tokenizer: PreTrainedTokenizer, prompt_length: int):
         self.tokenizer = tokenizer
@@ -61,6 +62,7 @@ def __call__(
 
         return False
 
+
 class OutputNumbersTokens(LogitsWarper):
     def __init__(self, tokenizer: PreTrainedTokenizer, prompt: str):
         self.tokenizer = tokenizer
@@ -82,3 +84,23 @@ def __call__(self, _, scores):
         scores[~mask] = -float("inf")
 
         return scores
+
+
+class OutputCommaAndBracketTokens(LogitsWarper):
+    def __init__(self, tokenizer: PreTrainedTokenizer, prompt: str):
+        self.tokenizer = tokenizer
+        self.tokenized_prompt = tokenizer(prompt, return_tensors="pt")
+        vocab_size = len(tokenizer)
+        self.allowed_mask = torch.zeros(vocab_size, dtype=torch.bool)
+
+        for _, token_id in tokenizer.get_vocab().items():
+            token_str = tokenizer.decode(token_id).strip()
+
+            if token_str in [",", "]"]:
+                self.allowed_mask[token_id] = True
+
+    def __call__(self, _, scores):
+        mask = self.allowed_mask.expand_as(scores)
+        scores[~mask] = -float("inf")
+
+        return scores

jsonformer/main.py

@@ -4,6 +4,7 @@
     NumberStoppingCriteria,
     OutputNumbersTokens,
     StringStoppingCriteria,
+    OutputCommaAndBracketTokens,
 )
 from termcolor import cprint
 from transformers import PreTrainedModel, PreTrainedTokenizer
@@ -34,6 +35,9 @@ def __init__(
         self.prompt = prompt
 
         self.number_logit_processor = OutputNumbersTokens(self.tokenizer, self.prompt)
+        self.array_end_logit_processor = OutputCommaAndBracketTokens(
+            self.tokenizer, self.prompt
+        )
 
         self.generation_marker = "|GENERATION|"
         self.debug_on = debug
@@ -80,7 +84,9 @@ def generate_number(self, temperature: Union[float, None] = None, iterations=0):
             if iterations > 3:
                 raise ValueError("Failed to generate a valid number")
 
-            return self.generate_number(temperature=self.temperature * 1.3, iterations=iterations+1)
+            return self.generate_number(
+                temperature=self.temperature * 1.3, iterations=iterations + 1
+            )
 
     def generate_boolean(self) -> bool:
         prompt = self.get_prompt()
@@ -195,27 +201,19 @@ def generate_array(self, item_schema: Dict[str, Any], obj: Dict[str, Any]) -> li
             obj.append(self.generation_marker)
             input_prompt = self.get_prompt()
             obj.pop()
-            input_tensor = self.tokenizer.encode(input_prompt, return_tensors="pt")
-            output = self.model.forward(input_tensor.to(self.model.device))
-            logits = output.logits[0, -1]
-
-
-            top_indices = logits.topk(30).indices
-            sorted_token_ids = top_indices[logits[top_indices].argsort(descending=True)]
-
-            found_comma = False
-            found_close_bracket = False
-
-            for token_id in sorted_token_ids:
-                decoded_token = self.tokenizer.decode(token_id)
-                if ',' in decoded_token:
-                    found_comma = True
-                    break
-                if ']' in decoded_token:
-                    found_close_bracket = True
-                    break
-
-            if found_close_bracket or not found_comma:
+            input_tokens = self.tokenizer.encode(input_prompt, return_tensors="pt").to(
+                self.model.device
+            )
+            response = self.model.generate(
+                input_tokens,
+                max_new_tokens=1,
+                num_return_sequences=1,
+                logits_processor=[self.array_end_logit_processor],
+                pad_token_id=self.tokenizer.eos_token_id,
+            )
+            last_token = self.tokenizer.decode(response[0][-1])
+
+            if "]" in last_token:
                 break
 
         return obj