001 /**
002 * BladeTreeSet.java
003 *
004 * This file is part of jclifford package and it's distributed under the terms of the MIT license.
005 *
006 * The MIT License :
007 * -----------------
008 * Copyright (c) 2002, 2003, 2004, 2005 Giorgio Vassallo, Pietro Brignola
009 *
010 * Permission is hereby granted, free of charge, to any person obtaining a
011 * copy of this software and associated documentation files (the "Software"),
012 * to deal in the Software without restriction, including without limitation
013 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
014 * and/or sell copies of the Software, and to permit persons to whom the
015 * Software is furnished to do so, subject to the following conditions:
016 * The above copyright notice and this permission notice shall be included in
017 * all copies or substantial portions of the Software.
018 *
019 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
020 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
021 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
022 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
023 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
024 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
025 * DEALINGS IN THE SOFTWARE.
026 */
027
028 package jclifford;
029
030 import java.util.Iterator;
031 import java.util.TreeSet;
032
033 /**
034 * <p>This class represents a TreeSet implementation of a blade (wedge product of generic basis versors).</p>
035 * <p>It is an utility class for the CliffordTreeSet class.</p>
036 * @version <p>0.9</p>
037 * @author <p>Realized by <a href="mailto:vassallo@csai.unipa.it">Giorgio Vassallo</a>, <a href="mailto:pietro.brignola@libero.it">Pietro Brignola</a>, November 2002.</p>
038 * @see Blade
039 * @see BladeBitSet
040 */
041 public class BladeTreeSet implements Comparable{
042
043 /**
044 * Tree set of the versors present in this blade. Empty blade represents a scalar.
045 */
046 private TreeSet treeset;
047
048 /**
049 * Creates and returns an new empty blade representing a scalar.
050 */
051 public BladeTreeSet()
052 {
053 treeset = new TreeSet();
054 }
055
056 /**
057 * Creates and returns an new Object deeply cloning this Object.
058 */
059 public Object clone()
060 {
061 //Creating a new empty blade
062 BladeTreeSet newbld = new BladeTreeSet();
063 //Defining an iterator on versors
064 Iterator it = treeset.iterator();
065 //For all versors
066 while(it.hasNext())
067 //Adding a copy to newbld
068 newbld.treeset.add(((Versor) it.next()).clone());
069 //Returning new Object
070 return newbld;
071 }
072
073 /**
074 * Puts specified versor in this blade if it is not already present.
075 * @param versor the specified versor to be put to the blade.
076 */
077 public void put(int versor)
078 {
079 treeset.add(new Versor(versor));
080 }
081
082 /**
083 * Compare this object with another comparing versors.
084 */
085 public int compareTo(Object object)
086 {
087 BladeTreeSet bld = (BladeTreeSet) object;
088 int result;
089 int grade1 = treeset.size();
090 int grade2 = bld.treeset.size();
091 //Comparing grades
092 if(grade1 < grade2)
093 return -1;
094 if(grade1 > grade2)
095 return 1;
096 //Comparing versors
097 Iterator it1 = treeset.iterator();
098 Iterator it2 = bld.treeset.iterator();
099 while(it1.hasNext()){
100 result = ((Versor) it1.next()).compareTo((Versor) it2.next());
101 if(result!=0)
102 return result;
103 }
104 //Blades are equals
105 return 0;
106 }
107
108 /**
109 * Returns the grade of this blade.
110 * @return the grade of the blade.
111 */
112 public int getGrade()
113 {
114 return treeset.size();
115 }
116
117 /**
118 * Computes the sign of the product with the specified blade.
119 * @param bld the second blade of the product.
120 * @return true if the sign of the product with the specified blade is negative, false otherwise.
121 */
122 boolean getSign(BladeTreeSet bld)
123 {
124 int sign = 0;
125 int count = 0;
126 //Indexes
127 int i1, i2, ix = 0;
128 //Defining ordered arrays of versors
129 Versor[] arrvers1 = (Versor[]) treeset.toArray(new Versor[0]);
130 Versor[] arrvers2 = (Versor[]) bld.treeset.toArray(new Versor[0]);
131 //Counting versors swapping
132 for(i1 = 0; i1 < arrvers1.length; ++i1){
133 sign ^= (count & 1);
134 for(i2 = ix; (i2<arrvers2.length)&&((arrvers2[i2]).versor<arrvers1[i1].versor);++i2){
135 sign ^= 1;
136 ++count;
137 }
138 ix = i2;
139 }
140 return sign != 0;
141 }
142
143 /**
144 * Computes the geometric product with the specified blade.
145 * @param bld the second blade of the geometric product.
146 * @return new blade from the geometric product with the specified blade.
147 */
148 BladeTreeSet geometricProduct(BladeTreeSet bld)
149 {
150 BladeTreeSet bld1 = (BladeTreeSet) clone();
151 BladeTreeSet bld2 = (BladeTreeSet) bld.clone();
152 BladeTreeSet newbld = (BladeTreeSet) clone();
153 newbld.treeset.removeAll(bld2.treeset);
154 bld2.treeset.removeAll(bld1.treeset);
155 newbld.treeset.addAll(bld2.treeset);
156 return newbld;
157 }
158
159 /**
160 * Computes the wedge product with the specified blade.
161 * @param bld the second blade of the wedge product.
162 * @return null if blades have common versors or a new blade from the wedge product with the specified blade.
163 */
164 BladeTreeSet wedgeProduct(BladeTreeSet bld)
165 {
166 BladeTreeSet newbld = (BladeTreeSet) clone();
167 newbld.treeset.retainAll(bld.treeset);
168 if(! newbld.treeset.isEmpty())
169 return null;
170 newbld = (BladeTreeSet) clone();
171 newbld.treeset.addAll(bld.treeset);
172 return newbld;
173 }
174
175 /**
176 * Computes the left contraction with the specified blade.
177 * @param bld the second blade of the left contraction.
178 * @return null if versors are not a subset of the specified blade, or a new blade from the left contraction with the specified blade.
179 */
180 BladeTreeSet leftContraction(BladeTreeSet bld)
181 {
182 if(! bld.treeset.containsAll(treeset))
183 return null;
184 BladeTreeSet newbld = (BladeTreeSet) bld.clone();
185 newbld.treeset.removeAll(treeset);
186 return newbld;
187 }
188
189 /**
190 * Computes the rignt contraction with the specified blade.
191 * @param bld the second blade of the right contraction.
192 * @return null if versors of the specified blade are not a subset of this blade, or a new blade from the left contraction with the specified blade.
193 */
194 BladeTreeSet rigthContraction(BladeTreeSet bld)
195 {
196 if(! treeset.containsAll(bld.treeset))
197 return null;
198 BladeTreeSet newbld = (BladeTreeSet) clone();
199 newbld.treeset.removeAll(bld.treeset);
200 return newbld;
201 }
202
203 /**
204 * Returns a string representation of this blade.
205 * @return the string representation of this blade.
206 */
207 public String toString()
208 {
209 //String representation of the blade
210 String str = new String();
211 //Defining an iterator on versors
212 Iterator it = treeset.iterator();
213 //For all blade-value mappings
214 while(it.hasNext())
215 str += ((Versor) it.next()).toString();
216 //Scalar case
217 if(str.length() == 0)
218 str += "scalar";
219 //Returning the string
220 return str;
221 }
222
223 }