1 package org.opentrafficsim.road.od;
2
3 import org.djunits.unit.FrequencyUnit;
4 import org.djunits.unit.TimeUnit;
5 import org.djunits.value.ValueRuntimeException;
6 import org.djunits.value.vdouble.scalar.Frequency;
7 import org.djunits.value.vdouble.scalar.Time;
8 import org.djunits.value.vdouble.vector.FrequencyVector;
9 import org.djunits.value.vdouble.vector.TimeVector;
10
11 /**
12 * Interpolation of demand.
13 * <p>
14 * Copyright (c) 2013-2023 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
15 * BSD-style license. See <a href="https://opentrafficsim.org/docs/license.html">OpenTrafficSim License</a>.
16 * </p>
17 * @author <a href="https://github.com/averbraeck">Alexander Verbraeck</a>
18 * @author <a href="https://tudelft.nl/staff/p.knoppers-1">Peter Knoppers</a>
19 * @author <a href="https://dittlab.tudelft.nl">Wouter Schakel</a>
20 */
21 public enum Interpolation
22 {
23
24 /** Stepwise interpolation of demand. */
25 STEPWISE
26 {
27 /** {@inheritDoc} */
28 @Override
29 Frequency interpolate(final Frequency frequency0, final Time time0, final Frequency frequency1, final Time time1,
30 final Time time)
31 {
32 return frequency0;
33 }
34
35 /** {@inheritDoc} */
36 @Override
37 int integrate(final Frequency frequency0, final Time time0, final Frequency frequency1, final Time time1)
38 {
39 return (int) (frequency0.getInUnit(FrequencyUnit.PER_HOUR)
40 * (time1.getInUnit(TimeUnit.BASE_HOUR) - time0.getInUnit(TimeUnit.BASE_HOUR)));
41 }
42 },
43
44 /** Linear interpolation of demand. */
45 LINEAR
46 {
47 /** {@inheritDoc} */
48 @Override
49 Frequency interpolate(final Frequency frequency0, final Time time0, final Frequency frequency1, final Time time1,
50 final Time time)
51 {
52 return Frequency.interpolate(frequency0, frequency1, (time.si - time0.si) / (time1.si - time0.si));
53 }
54
55 /** {@inheritDoc} */
56 @Override
57 int integrate(final Frequency frequency0, final Time time0, final Frequency frequency1, final Time time1)
58 {
59 return (int) (0.5 * (frequency0.getInUnit(FrequencyUnit.PER_HOUR) + frequency1.getInUnit(FrequencyUnit.PER_HOUR))
60 * (time1.getInUnit(TimeUnit.BASE_HOUR) - time0.getInUnit(TimeUnit.BASE_HOUR)));
61 }
62 };
63
64 /**
65 * Interpolate between given frequencies.
66 * @param frequency0 Frequency; frequency at {@code time0}
67 * @param time0 Time; time of {@code frequency0} (≤ {@code time})
68 * @param frequency1 Frequency; frequency at {@code time1}
69 * @param time1 Time; time of {@code frequency1} (> {@code time})
70 * @param time Time; {@code time0} ≤ {@code time} < {@code time1}
71 * @return interpolated frequency
72 */
73 abstract Frequency interpolate(Frequency frequency0, Time time0, Frequency frequency1, Time time1, Time time);
74
75 /**
76 * Integrates to the number of trips in given period.
77 * @param frequency0 Frequency; frequency at {@code time0}
78 * @param time0 Time; time of {@code frequency0} (≤ {@code time})
79 * @param frequency1 Frequency; frequency at {@code time1}
80 * @param time1 Time; time of {@code frequency1} (> {@code time})
81 * @return number of trips in given period
82 */
83 abstract int integrate(Frequency frequency0, Time time0, Frequency frequency1, Time time1);
84
85 /**
86 * @return whether this is step-wise interpolation
87 */
88 public boolean isStepWise()
89 {
90 return this.equals(STEPWISE);
91 }
92
93 /**
94 * @return whether this is linear interpolation
95 */
96 public boolean isLinear()
97 {
98 return this.equals(LINEAR);
99 }
100
101 /**
102 * Returns interpolated value from array at given time. If time is outside of the vector range, 0 is returned.
103 * @param time Time; time to determine the frequency at
104 * @param demandVector FrequencyVector; demand vector
105 * @param timeVector TimeVector; time vector
106 * @param sliceStart boolean; whether the time is at the start of an arbitrary time slice
107 * @return interpolated value from array at given time, or 0 when time is outside of range
108 */
109 public final Frequency interpolateVector(final Time time, final FrequencyVector demandVector, final TimeVector timeVector,
110 final boolean sliceStart)
111 {
112 try
113 {
114 // empty data or before start or after end, return 0
115 // case 1: t < t(0)
116 // case 2: sliceEnd & t == t(0), i.e. end of no-demand time before time array
117 // case 3: sliceStart & t == t(end), i.e. start of no-demand time after time array
118 // case 4: t > t(end)
119 if (timeVector.size() == 0 || (sliceStart ? time.lt(timeVector.get(0)) : time.le(timeVector.get(0))) || (sliceStart
120 ? time.ge(timeVector.get(timeVector.size() - 1)) : time.gt(timeVector.get(timeVector.size() - 1))))
121 {
122 return new Frequency(0.0, FrequencyUnit.PER_HOUR); // Frequency.ZERO give "Hz" which is not nice for flow
123 }
124 // interpolate
125 for (int i = 0; i < timeVector.size() - 1; i++)
126 {
127 // cases where we can take the slice from i to i+1
128 // case 1: sliceStart & t(i+1) > t [edge case: t(i) = t]
129 // case 2: sliceEnd & t(i+1) >= t [edge case: t(i+1) = t]
130 if (sliceStart ? timeVector.get(i + 1).gt(time) : timeVector.get(i + 1).ge(time))
131 {
132 return interpolate(demandVector.get(i), timeVector.get(i), demandVector.get(i + 1), timeVector.get(i + 1),
133 time);
134 }
135 }
136 }
137 catch (ValueRuntimeException ve)
138 {
139 // should not happen, vector lengths are checked when given is input
140 throw new RuntimeException("Index out of bounds.", ve);
141 }
142 // should not happen
143 throw new RuntimeException("Demand interpolation failed.");
144 }
145
146 }