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b2txt25/language_model/runtime/server/x86/python/lm_decoder.cc

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2025-07-02 12:18:09 -07:00
#include "pybind11/pybind11.h"
#include "pybind11/stl.h"
#include "pybind11/numpy.h"
#include "torch/script.h"
#include "decoder/brain_speech_decoder.h"
#include "utils/log.h"
namespace py = pybind11;
namespace wenet {
// Wrapper function to conver np array into torch tensor
void DecodeNumpy(BrainSpeechDecoder &decoder,
const py::array_t<float, py::array::c_style | py::array::forcecast> &input,
const py::array_t<float, py::array::c_style | py::array::forcecast> &log_priors_input,
const float blank_penalty) {
auto input_info = input.request();
auto log_priors_info = log_priors_input.request();
CHECK(input_info.ndim == 2);
CHECK(log_priors_info.ndim == 2);
float *input_data = static_cast<float *>(input_info.ptr);
float *log_priors_data = static_cast<float *>(log_priors_info.ptr);
torch::Tensor logits = torch::from_blob(
input_data, {input_info.shape[0], input_info.shape[1]}, torch::kFloat32);
torch::Tensor log_priors = torch::from_blob(
log_priors_data, {log_priors_info.shape[0], log_priors_info.shape[1]}, torch::kFloat32);
auto log_probs = torch::log_softmax(logits, -1);
log_probs = log_probs - log_priors;
auto blank_log_probs = log_probs.index({torch::indexing::Slice(),
torch::indexing::Slice(0, 1)});
log_probs.index_put_({torch::indexing::Slice(),
torch::indexing::Slice(0, 1)}, blank_log_probs - blank_penalty);
decoder.Decode(log_probs);
}
void DecodeNumpyLogProbs(BrainSpeechDecoder &decoder,
const py::array_t<float, py::array::c_style | py::array::forcecast> &input) {
auto input_info = input.request();
CHECK(input_info.ndim == 2);
float *input_data = static_cast<float *>(input_info.ptr);
torch::Tensor log_probs = torch::from_blob(
input_data, {input_info.shape[0], input_info.shape[1]}, torch::kFloat32);
decoder.Decode(log_probs);
}
PYBIND11_MODULE(lm_decoder, m) {
py::class_<DecodeOptions, std::shared_ptr<DecodeOptions> >(m, "DecodeOptions")
.def(py::init<int, int, float, float, float, float, float, int>());
py::class_<DecodeResource, std::shared_ptr<DecodeResource> >(m, "DecodeResource")
.def(py::init<const std::string &, const std::string &, const std::string &, const std::string &, const std::string &>());
py::class_<DecodeResult>(m, "DecodeResult")
.def_readonly("ac_score", &DecodeResult::ac_score)
.def_readonly("lm_score", &DecodeResult::lm_score)
.def_readonly("sentence", &DecodeResult::sentence);
py::class_<BrainSpeechDecoder>(m, "BrainSpeechDecoder")
.def(py::init<std::shared_ptr<DecodeResource>, std::shared_ptr<DecodeOptions> >())
.def("SetOpt", &BrainSpeechDecoder::SetOpt)
.def("Decode", &BrainSpeechDecoder::Decode)
.def("Rescore", &BrainSpeechDecoder::Rescore)
.def("Reset", &BrainSpeechDecoder::Reset)
.def("FinishDecoding", &BrainSpeechDecoder::FinishDecoding)
.def("DecodedSomething", &BrainSpeechDecoder::DecodedSomething)
.def("result", &BrainSpeechDecoder::result);
m.def("DecodeNumpy", &DecodeNumpy)
.def("DecodeNumpyLogProbs", &DecodeNumpyLogProbs);
}
} // namespace wenet