217 | | To further improve the quality of the search result, each search heuristic is enhanced by applying a local search after the search completes. The local search compares the best performance with neighboring coordinates. If a better coordinate is discovered, the local search continues recursively until no further improvement is possible. In the previous example, users can adjust the distance of the local search by modifying the value of the argument ''simplex_local_distance''. A local distance of two implies that the local search examines the performances of all neighbors within a distance of two. |
218 | | |
219 | | The following table lists all information about the search techniques implemented in the Orio's search engine. |
220 | | |
221 | | || '''Search technique''' || '''Algorithm-specific arguments''' || '''Argument's default value''' || |
222 | | || ''Exhaustive'' || - || - || |
223 | | || ''Random'' || - || - || |
224 | | || ''Nelder-Mead simplex'' || `local_distance` (i.e. the maximum distance of neighboring coordinates considered by the local search) [[BR]] `reflection_coef` [[BR]] `expansion_coef` [[BR]] `contraction_coef` [[BR]] `shrinkage_coef` || - || |
225 | | || ''Simulated annealing'' || - || - || |
| 217 | To further improve the quality of the search result, each search heuristic is enhanced by applying a local search after the search completes. The local search compares the best performance with neighboring coordinates. If a better coordinate is discovered, the local search continues recursively until no further improvement is possible. In the previous example, users can adjust the distance of the local search by modifying the value of the argument ''simplex_local_distance''. A local distance of two implies that the local search examines the performances of all neighbors within a distance of two. It is important to note that the local search is turned off by default for all search heuristics. Thus to activate the local search, Orio users must explicitly assign a positive integer value to the ''local_distance'' algorithm-specific argument. |
| 218 | |
| 219 | The following table lists information about the search techniques implemented in the Orio's search engine. |
| 220 | |
| 221 | || '''Search technique''' || '''Keyword''' || '''Algorithm-specific arguments''' || '''Default values''' || '''Argument description''' || |
| 222 | || ''Exhaustive'' || '`Exhaustive`' || - || - || |
| 223 | || ''Random'' || '`Random`' || `local_distance` || 0 || the maximum distance of neighboring coordinates considered by the local search || |
| 224 | || ''Nelder-Mead simplex'' || '`Simplex`' || `local_distance` [[BR]] `reflection_coef` [[BR]] `expansion_coef` [[BR]] `contraction_coef` [[BR]] `shrinkage_coef` || 0 [[BR]] 1.0 [[BR]] 2.0 [[BR]] 0.5 [[BR]] 0.5 || the maximum distance of neighboring coordinates considered by the local search [[BR]] |
| 225 | || ''Simulated annealing'' || '`Annealing`' || `local_distance` [[BR]] `cooling_factor` [[BR]] `final_temperature_ratio` [[BR]] `trials_limit` [[BR]] `moves_limit` || 0 [[BR]] 0.95 [[BR]] 0.05 [[BR]] 100 [[BR]] 20 || the maximum distance of neighboring coordinates considered by the local search [[BR]] the temperature reduction factor [[BR]] the percentage of the temperature used as a termination criterion |
| 226 | |
| 227 | (i.e. ) |