1 package org.opentrafficsim.core.egtf;
2
3 /**
4 * Gaussian implementation of a shape.
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 31 okt. 2018 <br>
10 * @author <a href="http://www.tbm.tudelft.nl/averbraeck">Alexander Verbraeck</a>
11 * @author <a href="http://www.tudelft.nl/pknoppers">Peter Knoppers</a>
12 * @author <a href="http://www.transport.citg.tudelft.nl">Wouter Schakel</a>
13 */
14 public class GaussKernelShape implements KernelShape
15 {
16
17 /** Twice the spatial size of the kernel to the power of 2. */
18 private final double sigma2;
19
20 /** Twice the temporal size of the kernel to the power of 2. */
21 private final double tau2;
22
23 /**
24 * Constructor.
25 * @param sigma double; spatial size of the kernel
26 * @param tau double; temporal size of the kernel
27 */
28 GaussKernelShape(final double sigma, final double tau)
29 {
30 this.sigma2 = 2.0 * sigma * sigma;
31 this.tau2 = 2.0 * tau * tau;
32 }
33
34 /** {@inheritDoc} */
35 @Override
36 public double weight(final double c, final double dx, final double dt)
37 {
38 double dtt = dt - dx / c;
39 return Math.exp(-(dx * dx) / this.sigma2 - dtt * dtt / this.tau2);
40 }
41
42 /** {@inheritDoc} */
43 @Override
44 public String toString()
45 {
46 return "GaussKernelShape [sigma=" + Math.sqrt(this.sigma2 / 2.0) + ", tau=" + Math.sqrt(this.tau2 / 2.0) + "]";
47 }
48
49 }