|
1
9
10 package org.nfunk.jep.function;
11
12 import java.util.*;
13 import org.nfunk.jep.*;
14
15 public class Cross extends PostfixMathCommand
16 {
17 static Subtract sub = new Subtract();
18 static Multiply mul = new Multiply();
19 public Cross()
20 {
21 numberOfParameters = 2;
22 }
23
24 public void run(Stack inStack)
25 throws ParseException
26 {
27 checkStack(inStack);
29 Object  param2 = inStack.pop();
30 Object param1 = inStack.pop();
31
32 inStack.push(cross(param1, param2));
33
34 return;
35 }
36
37 public Object cross(Object param1, Object param2)
38 throws ParseException
39 {
40 if (param1 instanceof Vector && param2 instanceof Vector)
41 {
42 return cross((Vector) param1,(Vector) param2);
43 }
44 throw new ParseException("Cross: Invalid parameter type, both arguments must be vectors");
45 }
46
47 public Object cross(Vector lhs,Vector rhs) throws ParseException
48 {
49 int len = lhs.size();
50 if((len!=2 && len!=3) || len !=rhs.size())
51 throw new ParseException("Cross: both sides must be of length 3");
52 if(len==3)
53 {
54 Vector res = new Vector(3);
55 res.setSize(3);
56 res.setElementAt(sub.sub(
57 mul.mul(lhs.elementAt(1),rhs.elementAt(2)),
58 mul.mul(lhs.elementAt(2),rhs.elementAt(1))),0);
59 res.setElementAt(sub.sub(
60 mul.mul(lhs.elementAt(2),rhs.elementAt(0)),
61 mul.mul(lhs.elementAt(0),rhs.elementAt(2))),1);
62 res.setElementAt(sub.sub(
63 mul.mul(lhs.elementAt(0),rhs.elementAt(1)),
64 mul.mul(lhs.elementAt(1),rhs.elementAt(0))),2);
65 return res;
66 }
67 else
68 {
69 return sub.sub(
70 mul.mul(lhs.elementAt(0),rhs.elementAt(1)),
71 mul.mul(lhs.elementAt(1),rhs.elementAt(0)));
72
73 }
74 }
75 }
76 |
Popular Tags |
Java API By Example, From Geeks To Geeks.