Mercurial > dive4elements > river

comparison artifacts/src/main/java/org/dive4elements/river/artifacts/model/LinearInterpolated.java @ 6152:0587819960c3

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Waterlevel differences & bed height differences: Add new model LinearInterpolated intented to unify the two very similiar calculations. The focus of the current implementation is correctness and not speed! The fact that the data sets more mostly sorted by station is not exploited. Doing so would improve performance significantly.
author Sascha L. Teichmann <teichmann@intevation.de>
date Sun, 02 Jun 2013 17:52:53 +0200
parents
children 12af732c9d0f
comparison
equal deleted inserted replaced
6151:63d1e2a9b311 6152:0587819960c3
1 /* Copyright (C) 2011, 2012, 2013 by Bundesanstalt für Gewässerkunde
2 * Software engineering by Intevation GmbH
3 *
4 * This file is Free Software under the GNU AGPL (>=v3)
5 * and comes with ABSOLUTELY NO WARRANTY! Check out the
6 * documentation coming with Dive4Elements River for details.
7 */
8
9 package org.dive4elements.river.artifacts.model;
10
11 import gnu.trove.TDoubleArrayList;
12
13 import java.io.Serializable;
14
15 import java.util.ArrayList;
16 import java.util.List;
17 import java.util.Set;
18 import java.util.TreeSet;
19
20 import org.apache.commons.math.stat.descriptive.moment.StandardDeviation;
21
22 import org.dive4elements.river.artifacts.math.Linear;
23
24 import org.dive4elements.river.utils.EpsilonComparator;
25
26 public class LinearInterpolated
27 implements Serializable
28 {
29 public static final double EPSILON = 1e-5;
30 public static final double MULTIPLE_STD_DEV = 4d;
31
32 public static final EpsilonComparator CMP = new EpsilonComparator(EPSILON);
33
34 private TDoubleArrayList xs;
35 private TDoubleArrayList ys;
36
37 private List<Range> gaps;
38
39 public interface Operator {
40 double evaluate(double y1, double y2);
41 } // interface Operator
42
43 public static final Operator SUB = new Operator() {
44 @Override
45 public double evaluate(double y1, double y2) {
46 return y1 - y2;
47 }
48 };
49
50 public static final Operator MAX = new Operator() {
51 @Override
52 public double evaluate(double y1, double y2) {
53 return Math.max(y1, y2);
54 }
55 };
56
57 public LinearInterpolated() {
58 xs = new TDoubleArrayList();
59 ys = new TDoubleArrayList();
60 }
61
62 public LinearInterpolated(int capacity) {
63 xs = new TDoubleArrayList(capacity);
64 ys = new TDoubleArrayList(capacity);
65 }
66
67 public void add(double x, double y) {
68 xs.add(x);
69 ys.add(y);
70 }
71
72 public int size() {
73 return xs.size();
74 }
75
76 public void pointsInRange(double from, double to, Set<Double> points) {
77 if (from > to) {
78 double t = from;
79 from = to;
80 to = t;
81 }
82 for (int i = 0, S = size(); i < S; ++i) {
83 double x = xs.getQuick(i);
84 if (x >= from && x <= to) {
85 points.add(x);
86 }
87 }
88 }
89
90 public boolean inGap(double x) {
91 if (gaps != null) {
92 for (Range gap: gaps) {
93 if (gap.inside(x)) {
94 return true;
95 }
96 }
97 }
98 return false;
99 }
100
101 public void detectGaps(double threshold) {
102 List<Range> gabs = new ArrayList<Range>();
103 for (int i = 1, S = size(); i < S; ++i) {
104 double x0 = xs.getQuick(i-1);
105 double x1 = xs.getQuick(i);
106 double minX, maxX;
107 if (x0 < x1) { minX = x0; maxX = x1; }
108 else { minX = x1; maxX = x0; }
109 double diff = maxX - minX - 2d*EPSILON;
110 if (diff > threshold) {
111 gaps.add(new Range(minX+EPSILON, maxX-EPSILON));
112 }
113 }
114 this.gaps = gaps.isEmpty() ? null : gabs;
115 }
116
117 public void resetGaps() {
118 gaps = null;
119 }
120
121 public double guessGapThreshold() {
122 return guessGapThreshold(MULTIPLE_STD_DEV);
123 }
124
125 public double guessGapThreshold(double scale) {
126 int S = size();
127 if (S < 5) { // Too less points.
128 return Double.MAX_VALUE;
129 }
130
131 StandardDeviation s = new StandardDeviation();
132
133 for (int i = 1; i < S; ++i) {
134 double diff = Math.abs(xs.getQuick(i-1) - xs.getQuick(i));
135 s.increment(diff);
136 }
137
138 return scale*s.getResult();
139 }
140
141 public double value(double x) {
142 for (int i = 0, S = size(); i < S; ++i) {
143 double x1 = xs.getQuick(i);
144 if (Math.abs(x1 - x) < EPSILON) {
145 return ys.getQuick(i);
146 }
147 if (i > 0) {
148 double x0 = xs.getQuick(i-1);
149 double minX, maxX;
150 if (x0 < x1) { minX = x0; maxX = x1; }
151 else { minX = x1; maxX = x0; }
152 if (x > minX && x < maxX) {
153 return Linear.linear(
154 x,
155 x0, x1,
156 ys.getQuick(i-1), ys.getQuick(i));
157 }
158 }
159 }
160 return Double.NaN;
161 }
162
163 public LinearInterpolated sub(
164 LinearInterpolated other,
165 double from,
166 double to
167 ) {
168 return apply(SUB, other, from, to);
169 }
170
171 public LinearInterpolated max(
172 LinearInterpolated other,
173 double from,
174 double to
175 ) {
176 return apply(MAX, other, from, to);
177 }
178
179 public LinearInterpolated apply(
180 Operator operator,
181 LinearInterpolated other,
182 double from,
183 double to
184 ) {
185 Set<Double> points = new TreeSet<Double>(CMP);
186 points.add(from);
187 points.add(to);
188
189 this .pointsInRange(from, to, points);
190 other.pointsInRange(from, to, points);
191
192 LinearInterpolated result = new LinearInterpolated();
193
194 for (double x: points) {
195 if (!inGap(x) && !other.inGap(x)) {
196 double y1 = this .value(x);
197 double y2 = other.value(x);
198 double y = operator.evaluate(y1, y2);
199 if (!Double.isNaN(y)) {
200 result.add(x, y);
201 }
202 }
203 }
204
205 return result;
206 }
207 }
208 // vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :
http://dive4elements.wald.intevation.org