mGPT/data/tools/tensors.py

# -*- coding: utf-8 -*-

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# Copyright©2020 Max-Planck-Gesellschaft zur Förderung
# der Wissenschaften e.V. (MPG). acting on behalf of its Max Planck Institute
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from typing import List, Dict
import torch
from torch import Tensor


def lengths_to_mask(lengths: List[int], device: torch.device) -> Tensor:
    lengths = torch.tensor(lengths, device=device)
    max_len = max(lengths)
    mask = torch.arange(max_len, device=device).expand(len(lengths), max_len) < lengths.unsqueeze(1)
    return mask