57 lines
2.0 KiB
C++
57 lines
2.0 KiB
C++
#include "lattice_rerank.h"
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#include "../neural/rescore_worker.h"
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#include <optional>
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#include <vector>
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namespace quanpin
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{
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LatticeReranker make_neural_reranker(const neural::SentenceModel *model, const std::string &context,
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const neural::RerankOptions &options)
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{
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if (model == nullptr)
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{
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return {};
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}
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// 在这里就把前文裁到模型真正会看的那几十个字：后台重排的结果表以「前文 + 候选句」为键，
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// 拿没裁过的整段历史当键的话，每上屏一个字键就变了，缓存永远打不中。
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const std::string trimmed = neural::last_characters(context, options.context_chars);
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return [model, context = trimmed, options](std::vector<LatticePath> &paths) -> bool {
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if (paths.size() < 2)
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{
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return false;
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}
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std::vector<std::string> sentences;
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std::vector<double> scores;
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sentences.reserve(paths.size());
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scores.reserve(paths.size());
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for (const LatticePath &path : paths)
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{
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sentences.push_back(path.sentence);
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scores.push_back(path.log_prob);
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}
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// 不在这里打分：交给后台线程，第一次必然落空，按词格的静态顺序先出候选。线程算完会叫
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// 醒会话重查一次，那一次才在结果表里拿到顺序。
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const std::optional<std::vector<std::size_t>> order =
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neural::RescoreWorker::instance().order_for(*model, context, sentences, scores, options);
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if (!order || order->size() != paths.size())
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{
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return false; // 还没算出来，或者模型自己弃权了：词格的顺序原样留着
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}
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std::vector<LatticePath> reordered;
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reordered.reserve(paths.size());
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for (std::size_t index : *order)
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{
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reordered.push_back(paths[index]);
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}
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paths = std::move(reordered);
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return true;
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};
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}
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} // namespace quanpin
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