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cde7fe4 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | #include "ctc_greedy_decoder.h"
#include "decoder_utils.h"
std::string ctc_greedy_decoder(
const std::vector<std::vector<double>> &probs_seq,
const std::vector<std::string> &vocabulary) {
// dimension check
size_t num_time_steps = probs_seq.size();
for (size_t i = 0; i < num_time_steps; ++i) {
VALID_CHECK_EQ(probs_seq[i].size(),
vocabulary.size() + 1,
"The shape of probs_seq does not match with "
"the shape of the vocabulary");
}
size_t blank_id = vocabulary.size();
std::vector<size_t> max_idx_vec(num_time_steps, 0);
std::vector<size_t> idx_vec;
for (size_t i = 0; i < num_time_steps; ++i) {
double max_prob = 0.0;
size_t max_idx = 0;
const std::vector<double> &probs_step = probs_seq[i];
for (size_t j = 0; j < probs_step.size(); ++j) {
if (max_prob < probs_step[j]) {
max_idx = j;
max_prob = probs_step[j];
}
}
// id with maximum probability in current time step
max_idx_vec[i] = max_idx;
// deduplicate
if ((i == 0) || ((i > 0) && max_idx_vec[i] != max_idx_vec[i - 1])) {
idx_vec.push_back(max_idx_vec[i]);
}
}
std::string best_path_result;
for (size_t i = 0; i < idx_vec.size(); ++i) {
if (idx_vec[i] != blank_id) {
best_path_result += vocabulary[idx_vec[i]];
}
}
return best_path_result;
}
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