fconv.py 文件源码

def make_positions(tokens, padding_idx, left_pad, offset=0):
    seqlen = tokens.size(1)
    if not hasattr(make_positions, 'range'):
        make_positions.range = tokens.new()
    if make_positions.range.numel() < offset + seqlen:
        # offset positions by the padding index
        torch.arange(padding_idx + 1, padding_idx + 1 + offset + seqlen,
                     out=make_positions.range)
    mask = tokens.ne(padding_idx)
    positions = make_positions.range[offset:offset+seqlen].expand_as(tokens)
    if left_pad:
        positions = positions - mask.size(1) + mask.long().sum(dim=1).unsqueeze(1)
    return tokens.clone().masked_scatter_(mask, positions[mask])