How to modify this code to output multi candidate results by beam search

[JRMeyer]

>>> jackhuang
[May 6, 2018, 12:50pm]

This code is in 'deepspeech.cc'(deepspeech 0.1.1) slash
I want to make the 'top_paths' to 5, since I want to get 5 candidate
results. However, the 'decoder_outputs' will not get 5 results, so it
can not works. How to make it?

char*
Model::decode(int aNFrames, float*** aLogits)
{
const int batch_size = BATCH_SIZE;
const int top_paths = 1; // I change this to 5
const int timesteps = aNFrames;
const size_t num_classes = mPriv->alphabet->GetSize() + 1; // +1 for blank

// Raw data containers (arrays of floats, ints, etc.).
int sequence_lengths[batch_size] = {timesteps};

// Convert data containers to the format accepted by the decoder, simply
// mapping the memory from the container to an Eigen::ArrayXi,::MatrixXf,
// using Eigen::Map.
Eigen::Map seq_len(&sequence_lengths[0], batch_size);
std::vector<Eigen::Map> inputs;
inputs.reserve(timesteps);
for (int t = 0; t < timesteps; ++t) {
inputs.emplace_back(&aLogits[t][0][0], batch_size, num_classes);
}

// Prepare containers for output and scores.
// CTCDecoder::Output is std::vector<std::vector>
std::vectorCTCDecoder::Output decoder_outputs(top_paths);
for (CTCDecoder::Output& output : decoder_outputs) {
output.resize(batch_size);
}
float score[batch_size][top_paths] = {{0.0}};
Eigen::MapEigen::MatrixXf scores(&score[0][0], batch_size, top_paths);

if (mPriv->scorer == NULL) {
CTCBeamSearchDecoder<>::DefaultBeamScorer scorer;
CTCBeamSearchDecoder<> decoder(num_classes,
mPriv->beam_width,
&scorer,
batch_size);
decoder.Decode(seq_len, inputs, &decoder_outputs, &scores).ok();
} else {
CTCBeamSearchDecoder decoder(num_classes,
mPriv->beam_width,
mPriv->scorer,
batch_size);
decoder.Decode(seq_len, inputs, &decoder_outputs, &scores).ok();
}

// Output is an array of shape (1, n_results, result_length).
// In this case, n_results is also equal to 1.
size_t output_length = decoder_outputs[0][0].size() + 1;
size_t decoded_length = 1; // add 1 for the slash 0
for (int i = 0; i < output_length - 1; i++) {
int64 character = decoder_outputs[0][0][i];
const std::string& str = mPriv->alphabet->StringFromLabel(character);
decoded_length += str.size();
}

char* output = (char*)malloc(sizeof(char) DEEPSPEECH.cdx deepspeech.commands DEEPSPEECH.pages DEEPSPEECH.warc.gz discourse.mozilla.org html-to-markdown.sh shell-conver-html-to-split-posts.sh sorted-deepspeech-posts decoded_length);
char* pen = output;
for (int i = 0; i < output_length - 1; i++) {
int64 character = decoder_outputs[0][0][i];
const std::string& str = mPriv->alphabet->StringFromLabel(character);
strncpy(pen, str.c_str(), str.size());
pen += str.size();
}
*pen = ' slash 0';

for (int i = 0; i < timesteps; ++i) {
for (int j = 0; j < batch_size; ++j) {
free(aLogits[i][j]);
}
free(aLogits[i]);
}
free(aLogits);

return output;
}

[This is an archived TTS discussion thread from discourse.mozilla.org/t/how-to-modify-this-code-to-output-multi-candidate-results-by-beam-search]

[JRMeyer]

>>> jackhuang
[May 6, 2018, 12:50pm]

This code is in 'deepspeech.cc'(deepspeech 0.1.1) slash
I want to make the 'top_paths' to 5, since I want to get 5 candidate
results. However, the 'decoder_outputs' will not get 5 results, so it
can not works. How to make it?

char*
Model::decode(int aNFrames, float*** aLogits)
{
const int batch_size = BATCH_SIZE;
const int top_paths = 1; // I change this to 5
const int timesteps = aNFrames;
const size_t num_classes = mPriv->alphabet->GetSize() + 1; // +1 for blank

// Raw data containers (arrays of floats, ints, etc.).
int sequence_lengths[batch_size] = {timesteps};

// Convert data containers to the format accepted by the decoder, simply
// mapping the memory from the container to an Eigen::ArrayXi,::MatrixXf,
// using Eigen::Map.
Eigen::Map seq_len(&sequence_lengths[0], batch_size);
std::vector<Eigen::Map> inputs;
inputs.reserve(timesteps);
for (int t = 0; t < timesteps; ++t) {
inputs.emplace_back(&aLogits[t][0][0], batch_size, num_classes);
}

// Prepare containers for output and scores.
// CTCDecoder::Output is std::vector<std::vector>
std::vectorCTCDecoder::Output decoder_outputs(top_paths);
for (CTCDecoder::Output& output : decoder_outputs) {
output.resize(batch_size);
}
float score[batch_size][top_paths] = {{0.0}};
Eigen::MapEigen::MatrixXf scores(&score[0][0], batch_size, top_paths);

if (mPriv->scorer == NULL) {
CTCBeamSearchDecoder<>::DefaultBeamScorer scorer;
CTCBeamSearchDecoder<> decoder(num_classes,
mPriv->beam_width,
&scorer,
batch_size);
decoder.Decode(seq_len, inputs, &decoder_outputs, &scores).ok();
} else {
CTCBeamSearchDecoder decoder(num_classes,
mPriv->beam_width,
mPriv->scorer,
batch_size);
decoder.Decode(seq_len, inputs, &decoder_outputs, &scores).ok();
}

// Output is an array of shape (1, n_results, result_length).
// In this case, n_results is also equal to 1.
size_t output_length = decoder_outputs[0][0].size() + 1;
size_t decoded_length = 1; // add 1 for the slash 0
for (int i = 0; i < output_length - 1; i++) {
int64 character = decoder_outputs[0][0][i];
const std::string& str = mPriv->alphabet->StringFromLabel(character);
decoded_length += str.size();
}

char* output = (char*)malloc(sizeof(char) DEEPSPEECH.cdx deepspeech.commands DEEPSPEECH.pages DEEPSPEECH.warc.gz discourse.mozilla.org html-to-markdown.sh shell-conver-html-to-split-posts.sh sorted-deepspeech-posts decoded_length);
char* pen = output;
for (int i = 0; i < output_length - 1; i++) {
int64 character = decoder_outputs[0][0][i];
const std::string& str = mPriv->alphabet->StringFromLabel(character);
strncpy(pen, str.c_str(), str.size());
pen += str.size();
}
*pen = ' slash 0';

for (int i = 0; i < timesteps; ++i) {
for (int j = 0; j < batch_size; ++j) {
free(aLogits[i][j]);
}
free(aLogits[i]);
}
free(aLogits);

return output;
}

[This is an archived TTS discussion thread from discourse.mozilla.org/t/how-to-modify-this-code-to-output-multi-candidate-results-by-beam-search]