public Object cross(Vector lhs, Vector rhs) throws ParseException {
int len = lhs.size();
if ((len != 2 && len != 3) || len != rhs.size())
throw new ParseException("Cross: both sides must be of length 3");
if (len == 3) {
Vector res = new Vector(3);
res.setSize(3);
res.setElementAt(
sub.sub(
mul.mul(lhs.elementAt(1), rhs.elementAt(2)),
mul.mul(lhs.elementAt(2), rhs.elementAt(1))),
0);
res.setElementAt(
sub.sub(
mul.mul(lhs.elementAt(2), rhs.elementAt(0)),
mul.mul(lhs.elementAt(0), rhs.elementAt(2))),
1);
res.setElementAt(
sub.sub(
mul.mul(lhs.elementAt(0), rhs.elementAt(1)),
mul.mul(lhs.elementAt(1), rhs.elementAt(0))),
2);
return res;
} else {
return sub.sub(
mul.mul(lhs.elementAt(0), rhs.elementAt(1)), mul.mul(lhs.elementAt(1), rhs.elementAt(0)));
}
}
public Object dot(Vector v1, Vector v2) throws ParseException {
if (v1.size() != v2.size())
throw new ParseException("Dot: both sides of dot must be same length");
int len = v1.size();
if (len < 1) throw new ParseException("Dot: empty vectors parsed");
Object res = mul.mul(v1.elementAt(0), v2.elementAt(0));
for (int i = 1; i < len; ++i) {
res = add.add(res, mul.mul(v1.elementAt(i), v2.elementAt(i)));
}
return res;
}