Iluvatar-mrv100 SDK 4.3.0

vllm/model_executor/layers/utils.py

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+# SPDX-License-Identifier: Apache-2.0
+"""Utility methods for model layers."""
+from typing import Tuple
+
+import torch
+
+
+def get_token_bin_counts_and_mask(
+    tokens: torch.Tensor,
+    vocab_size: int,
+    num_seqs: int,
+) -> Tuple[torch.Tensor, torch.Tensor]:
+    # Compute the bin counts for the tokens.
+    # vocab_size + 1 for padding.
+    bin_counts = torch.zeros((num_seqs, vocab_size + 1),
+                             dtype=torch.long,
+                             device=tokens.device)
+    bin_counts.scatter_add_(1, tokens, torch.ones_like(tokens))
+    bin_counts = bin_counts[:, :vocab_size]
+    mask = bin_counts > 0
+
+    return bin_counts, mask
+
+
+def apply_penalties(logits: torch.Tensor, prompt_tokens_tensor: torch.Tensor,
+                    output_tokens_tensor: torch.Tensor,
+                    presence_penalties: torch.Tensor,
+                    frequency_penalties: torch.Tensor,
+                    repetition_penalties: torch.Tensor) -> torch.Tensor:
+    """
+    Applies penalties in place to the logits tensor
+    logits : The input logits tensor of shape [num_seqs, vocab_size]
+    prompt_tokens_tensor: A tensor containing the prompt tokens. The prompts 
+        are padded to the maximum prompt length within the batch using 
+        `vocab_size` as the padding value. The value `vocab_size` is used 
+        for padding because it does not correspond to any valid token ID 
+        in the vocabulary.
+    output_tokens_tensor: The output tokens tensor.
+    presence_penalties: The presence penalties of shape (num_seqs, )
+    frequency_penalties: The frequency penalties of shape (num_seqs, )
+    repetition_penalties: The repetition penalties of shape (num_seqs, )
+    """
+    num_seqs, vocab_size = logits.shape
+    _, prompt_mask = get_token_bin_counts_and_mask(prompt_tokens_tensor,
+                                                   vocab_size, num_seqs)
+    output_bin_counts, output_mask = get_token_bin_counts_and_mask(
+        output_tokens_tensor, vocab_size, num_seqs)
+    repetition_penalties = repetition_penalties.unsqueeze(dim=1).repeat(
+        1, vocab_size)
+    logits[logits > 0] /= torch.where(prompt_mask | output_mask,
+                                      repetition_penalties, 1.0)[logits > 0]
+    logits[logits <= 0] *= torch.where(prompt_mask | output_mask,
+                                       repetition_penalties, 1.0)[logits <= 0]
+    # We follow the definition in OpenAI API.
+    # Refer to https://platform.openai.com/docs/api-reference/parameter-details
+    logits -= frequency_penalties.unsqueeze(dim=1) * output_bin_counts
+    logits -= presence_penalties.unsqueeze(dim=1) * output_mask
+    return logits