| /* |
| * Copyright (C) 2017 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License |
| */ |
| package com.android.settings.dashboard.suggestions; |
| |
| import com.android.settingslib.drawer.Tile; |
| |
| import android.support.annotation.VisibleForTesting; |
| |
| import java.util.Collections; |
| import java.util.Comparator; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| public class SuggestionRanker { |
| |
| private static final String TAG = "SuggestionRanker"; |
| |
| // The following coefficients form a linear model, which mixes the features to obtain a |
| // relevance metric for ranking the suggestion items. This model is learned with off-line data |
| // by training a binary classifier to detect the clicked items. The higher the obtained |
| // relevance metric, the higher chance of getting clicked. |
| private static final Map<String, Double> WEIGHTS = new HashMap<String, Double>() {{ |
| put(SuggestionFeaturizer.FEATURE_IS_SHOWN, 5.05140842519); |
| put(SuggestionFeaturizer.FEATURE_IS_DISMISSED, 2.29641455171); |
| put(SuggestionFeaturizer.FEATURE_IS_CLICKED, -2.98812233623); |
| put(SuggestionFeaturizer.FEATURE_TIME_FROM_LAST_SHOWN, 5.02807250202); |
| put(SuggestionFeaturizer.FEATURE_TIME_FROM_LAST_DISMISSED, 2.49589700842); |
| put(SuggestionFeaturizer.FEATURE_TIME_FROM_LAST_CLICKED, -4.3377039948); |
| put(SuggestionFeaturizer.FEATURE_SHOWN_COUNT, -2.35993512546); |
| }}; |
| |
| private final SuggestionFeaturizer mSuggestionFeaturizer; |
| |
| private final Map<Tile, Double> relevanceMetrics; |
| |
| Comparator<Tile> suggestionComparator = new Comparator<Tile>() { |
| @Override |
| public int compare(Tile suggestion1, Tile suggestion2) { |
| return relevanceMetrics.get(suggestion1) < relevanceMetrics.get(suggestion2) ? 1 : -1; |
| } |
| }; |
| |
| public SuggestionRanker(SuggestionFeaturizer suggestionFeaturizer) { |
| mSuggestionFeaturizer = suggestionFeaturizer; |
| relevanceMetrics = new HashMap<Tile, Double>(); |
| } |
| |
| public void rankSuggestions(final List<Tile> suggestions, List<String> suggestionIds) { |
| relevanceMetrics.clear(); |
| Map<String, Map<String, Double>> features = mSuggestionFeaturizer.featurize(suggestionIds); |
| for (int i = 0; i < suggestionIds.size(); i++) { |
| relevanceMetrics.put(suggestions.get(i), |
| getRelevanceMetric(features.get(suggestionIds.get(i)))); |
| } |
| Collections.sort(suggestions, suggestionComparator); |
| } |
| |
| @VisibleForTesting |
| double getRelevanceMetric(Map<String, Double> features) { |
| double sum = 0; |
| if (features == null) { |
| return sum; |
| } |
| for (String feature : WEIGHTS.keySet()) { |
| sum += WEIGHTS.get(feature) * features.get(feature); |
| } |
| return sum; |
| } |
| } |