1 /*
2 * BarrelCylinderSegmentationBase.java 20051124 - G.Lima - Created
3 */
4
5 package org.lcsim.geometry.segmentation;
6
7 import org.jdom.Element;
8 import org.lcsim.geometry.layer.Layer;
9 import org.lcsim.geometry.layer.LayerStack;
10
11 /**
12 * Base implementation of a barrel segmentation, it provides common code
13 * implementation.
14 *
15 * @author Guilherme Lima
16 * @version $Id: BarrelCylinderSegmentationBase.java,v 1.1 2005/12/07 10:39:37
17 * lima Exp $
18 */
19 // FIXME This can probably be folded into some other class. It only has one method.
20 public abstract class BarrelCylinderSegmentationBase extends SegmentationBase
21 {
22 public BarrelCylinderSegmentationBase(Element e)
23 {
24 super(e);
25 }
26
27 /**
28 * Return the layer number based on the radial distance to cylinder axis.
29 *
30 * @param r
31 * radial distance to cylinder axis
32 * @return layer number of layer corresponding to that distance (may be
33 * either in absorber or live material)
34 */
35 public int getLayerBin(double r)
36 {
37 // In order to be general, we should not assume that all
38 // layers have the same thickness. Therefore, one has to
39 // guess the starting layer (based on average thickness), and
40 // then navigate through layers until one finds the right one
41 double depth = r - getRMin();
42 double mean_t = (getRMax() - getRMin()) / getNumberOfLayers();
43
44 int ilay = (int) Math.floor(depth / mean_t);
45 LayerStack stack = getLayering().getLayers();
46 Layer layer = stack.getLayer(ilay);
47 double depHi = stack.getThicknessToLayerBack(ilay);
48 double depLo = depHi - layer.getThickness();
49 for (;;)
50 {
51 if (depth > depLo && depth <= depHi)
52 return ilay;
53 if (depth <= depLo)
54 {
55 --ilay;
56 depHi = depLo;
57 layer = stack.getLayer(ilay);
58 depLo -= layer.getThickness();
59 }
60 if (depth > depHi)
61 {
62 ++ilay;
63 depLo = depHi;
64 layer = stack.getLayer(ilay);
65 depHi += layer.getThickness();
66 }
67 }
68 }
69 }