Move everything into the tortoise/ subdirectory

For eventual packaging.

tortoise/utils/typical_sampling.py

@@ -0,0 +1,33 @@
+import torch
+from transformers import LogitsWarper
+
+
+class TypicalLogitsWarper(LogitsWarper):
+    def __init__(self, mass: float = 0.9, filter_value: float = -float("Inf"), min_tokens_to_keep: int = 1):
+        self.filter_value = filter_value
+        self.mass = mass
+        self.min_tokens_to_keep = min_tokens_to_keep
+
+    def __call__(self, input_ids: torch.LongTensor, scores: torch.FloatTensor) -> torch.FloatTensor:
+        # calculate entropy
+        normalized = torch.nn.functional.log_softmax(scores, dim=-1)
+        p = torch.exp(normalized)
+        ent = -(normalized * p).nansum(-1, keepdim=True)
+
+        # shift and sort
+        shifted_scores = torch.abs((-normalized) - ent)
+        sorted_scores, sorted_indices = torch.sort(shifted_scores, descending=False)
+        sorted_logits = scores.gather(-1, sorted_indices)
+        cumulative_probs = sorted_logits.softmax(dim=-1).cumsum(dim=-1)
+
+        # Remove tokens with cumulative mass above the threshold
+        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
+        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)
+        return scores