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Skip computing viterbi if viterbi of previous state is lower than lower bound

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This causes a speedup of 300%.
This commit is contained in:
Patrick Niklaus 2015-02-09 00:19:42 +01:00
parent dc1405ffa8
commit 0637215b85
1 changed files with 7 additions and 2 deletions
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9
routing_algorithms/map_matching.hpp
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@ -377,9 +377,15 @@ template <class DataFacadeT> class MapMatching final
for (auto s_prime = 0u; s_prime < current_viterbi.size(); ++s_prime) for (auto s_prime = 0u; s_prime < current_viterbi.size(); ++s_prime)
{ {
double new_value = prev_viterbi[s];
if (current_viterbi[s_prime] > new_value)
continue;
// how likely is candidate s_prime at time t to be emitted? // how likely is candidate s_prime at time t to be emitted?
const double emission_pr = log_emission_probability(timestamp_list[t][s_prime].second); const double emission_pr = log_emission_probability(timestamp_list[t][s_prime].second);
new_value += emission_pr;
if (current_viterbi[s_prime] > new_value)
continue;
// get distance diff between loc1/2 and locs/s_prime // get distance diff between loc1/2 and locs/s_prime
const auto d_t = get_distance_difference(prev_coordinate, const auto d_t = get_distance_difference(prev_coordinate,
@ -387,9 +393,8 @@ template <class DataFacadeT> class MapMatching final
prev_unbroken_timestamps_list[s].first, prev_unbroken_timestamps_list[s].first,
current_timestamps_list[s_prime].first); current_timestamps_list[s_prime].first);
// plug probabilities together
const double transition_pr = log_transition_probability(d_t, beta); const double transition_pr = log_transition_probability(d_t, beta);
const double new_value = prev_viterbi[s] + emission_pr + transition_pr; new_value += transition_pr;
JSON::Array _debug_element = makeJSONArray( JSON::Array _debug_element = makeJSONArray(
makeJSONSafe(prev_viterbi[s]), makeJSONSafe(prev_viterbi[s]),