1 package org.opentrafficsim.core.egtf;
2
3 /**
4 * Exponential implementation of a shape. Used as default when kernels are created.
5 * <p>
6 * Copyright (c) 2013-2019 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
7 * BSD-style license. See <a href="http://opentrafficsim.org/node/13">OpenTrafficSim License</a>.
8 * <p>
9 * @version $Revision$, $LastChangedDate$, by $Author$, initial version 24 okt. 2018 <br>
10 * @author <a href="http://www.transport.citg.tudelft.nl">Wouter Schakel</a>
11 */
12 public class ExpKernelShape implements KernelShape
13 {
14
15 /** Spatial size of the kernel. */
16 private final double sigma;
17
18 /** Temporal size of the kernel. */
19 private final double tau;
20
21 /**
22 * Constructor.
23 * @param sigma double; spatial size of the kernel
24 * @param tau double; temporal size of the kernel
25 */
26 ExpKernelShape(final double sigma, final double tau)
27 {
28 this.sigma = sigma;
29 this.tau = tau;
30 }
31
32 /** {@inheritDoc} */
33 @Override
34 public double weight(final double c, final double dx, final double dt)
35 {
36 return Math.exp(-Math.abs(dx) / this.sigma - Math.abs(dt - dx / c) / this.tau);
37 }
38
39 /** {@inheritDoc} */
40 @Override
41 public String toString()
42 {
43 return "ExpKernelShape [sigma=" + this.sigma + ", tau=" + this.tau + "]";
44 }
45
46 }