| /* |
| * Copyright (C) 2012 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 android.bordeaux.services; |
| import android.location.Location; |
| import android.text.format.Time; |
| import android.util.Log; |
| |
| import java.lang.Math; |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| public class BaseCluster { |
| |
| public static String TAG = "BaseCluster"; |
| |
| public double[] mCenter; |
| // protected double[] mCenter; |
| |
| // Histogram illustrates the pattern of visit during time of day, |
| protected HashMap<String, Long> mHistogram = new HashMap<String, Long>(); |
| |
| protected long mAvgInterval; |
| protected long mDuration; |
| |
| protected String mSemanticId; |
| |
| protected static final double EARTH_RADIUS = 6378100f; |
| |
| public BaseCluster(Location location, long avgInterval) { |
| mAvgInterval = avgInterval; |
| mCenter = getLocationVector(location); |
| |
| mDuration = 0; |
| } |
| |
| public BaseCluster() { |
| } |
| |
| public String getSemanticId() { |
| return mSemanticId; |
| } |
| |
| protected void generateSemanticId(long index) { |
| mSemanticId = "cluser: " + String.valueOf(index); |
| } |
| |
| public void setSemanticId(String semanticId) { |
| mSemanticId = semanticId; |
| } |
| |
| public boolean hasSemanticId() { |
| return mSemanticId != null; |
| } |
| |
| protected double[] getLocationVector(Location location) { |
| return getLocationVector(location.getLongitude(), location.getLatitude()); |
| } |
| |
| protected double[] getLocationVector(double longitude, double latitude) { |
| double vector[] = new double[3]; |
| double lambda = Math.toRadians(longitude); |
| double phi = Math.toRadians(latitude); |
| |
| vector[0] = Math.cos(lambda) * Math.cos(phi); |
| vector[1] = Math.sin(lambda) * Math.cos(phi); |
| vector[2] = Math.sin(phi); |
| return vector; |
| } |
| |
| protected double getCenterLongitude() { |
| // Because latitude ranges from -90 to 90 degrees, cosPhi >= 0. |
| double cosPhi = Math.cos(Math.asin(mCenter[2])); |
| double longitude = Math.toDegrees(Math.asin(mCenter[1] / cosPhi)); |
| if (mCenter[0] < 0) { |
| longitude = (longitude > 0) ? 180f - longitude : -180 - longitude; |
| } |
| return longitude; |
| } |
| |
| protected double getCenterLatitude() { |
| return Math.toDegrees(Math.asin(mCenter[2])); |
| } |
| |
| private double computeDistance(double[] vector1, double[] vector2) { |
| double product = 0f; |
| for (int i = 0; i < 3; ++i) { |
| product += vector1[i] * vector2[i]; |
| } |
| double radian = Math.acos(Math.min(product, 1f)); |
| return radian * EARTH_RADIUS; |
| } |
| |
| /* |
| * This computes the distance from loation to the cluster center in meter. |
| */ |
| public float distanceToCenter(Location location) { |
| return (float) computeDistance(mCenter, getLocationVector(location)); |
| } |
| |
| public float distanceToCluster(BaseCluster cluster) { |
| return (float) computeDistance(mCenter, cluster.mCenter); |
| } |
| |
| public void absorbCluster(BaseCluster cluster) { |
| if (cluster.mAvgInterval != mAvgInterval) { |
| throw new RuntimeException( |
| "aborbing cluster failed: inconsistent average invergal "); |
| } |
| |
| // the new cluster center is the average of the two clusters. |
| double currWeight = ((double) mDuration) / (mDuration + cluster.mDuration); |
| double newWeight = 1f - currWeight; |
| double norm = 0; |
| for (int i = 0; i < 3; ++i) { |
| mCenter[i] = currWeight * mCenter[i] + newWeight * cluster.mCenter[i]; |
| norm += mCenter[i] * mCenter[i]; |
| } |
| // normalize the center to be unit vector |
| for (int i = 0; i < 3; ++i) { |
| mCenter[i] /= norm; |
| } |
| absorbHistogram(cluster); |
| } |
| |
| public void setCluster(BaseCluster cluster) { |
| for (int i = 0; i < 3; ++i) { |
| mCenter[i] = cluster.mCenter[i]; |
| } |
| mHistogram.clear(); |
| mHistogram.putAll(cluster.mHistogram); |
| mDuration = cluster.mDuration; |
| } |
| |
| private void absorbHistogram(BaseCluster cluster) { |
| for (Map.Entry<String, Long> entry : cluster.mHistogram.entrySet()) { |
| String timeLabel = entry.getKey(); |
| long duration = entry.getValue(); |
| |
| if (mHistogram.containsKey(timeLabel)) { |
| duration += mHistogram.get(timeLabel); |
| } |
| mHistogram.put(timeLabel, duration); |
| } |
| mDuration += cluster.mDuration; |
| } |
| |
| public boolean passThreshold(long durationThreshold) { |
| // TODO: might want to keep semantic cluster |
| return mDuration > durationThreshold; |
| } |
| |
| public final HashMap<String, Long> getHistogram() { |
| return mHistogram; |
| } |
| |
| public void setHistogram(Map<String, Long> histogram) { |
| mHistogram.clear(); |
| mHistogram.putAll(histogram); |
| |
| mDuration = 0; |
| if (mHistogram.containsKey(TimeStatsAggregator.WEEKEND)) { |
| mDuration += mHistogram.get(TimeStatsAggregator.WEEKEND); |
| } |
| if (mHistogram.containsKey(TimeStatsAggregator.WEEKDAY)) { |
| mDuration += mHistogram.get(TimeStatsAggregator.WEEKDAY); |
| } |
| } |
| } |