/*
* Open Source Physics software is free software as described near the bottom of this code file.
*
* For additional information and documentation on Open Source Physics please see:
* <http://www.opensourcephysics.org/>
*/
package org.opensourcephysics.numerics;
/**
* A 3-element vector that is represented by double-precision floating point
* x,y,z coordinates.
*/
public class Vec3D {
public double x, y, z;
/**
* Constructs and initializes a Vector3d from the specified xyz coordinates.
* @param x the x coordinate
* @param y the y coordinate
* @param z the z coordinate
*/
public Vec3D(double x, double y, double z) {
this.x = x;
this.y = y;
this.z = z;
}
/**
* Constructs and initializes a Vector3d from the array of length 3.
* @param v the array of length 3 containing xyz in order
*/
public Vec3D(double[] v) {
x = v[0];
y = v[1];
z = v[2];
}
/**
* Constructs and initializes a Vector3d from the specified Vector3d.
* @param v1 the Vector3d containing the initialization x y z data
*/
public Vec3D(Vec3D v1) {
x = v1.x;
y = v1.y;
z = v1.z;
}
/**
* Constructs and initializes it to (0,0,0).
*/
public Vec3D() {
this(0, 0, 0);
}
/**
* Sets this vector to the vector subtraction of vectors v1 and v2.
* @param v1 the first vector
* @param v2 the second vector
*/
public final void subtract(Vec3D v1, Vec3D v2) {
this.x = v1.x-v2.x;
this.y = v1.y-v2.y;
this.z = v1.z-v2.z;
}
/**
* Sets this vector to the vector addition of vectors v1 and v2.
* @param v1 the first vector
* @param v2 the second vector
*/
public final void add(Vec3D v1, Vec3D v2) {
this.x = v1.x+v2.x;
this.y = v1.y+v2.y;
this.z = v1.z+v2.z;
}
/**
* Sets this vector to the vector cross product of vectors v1 and v2.
* @param v1 the first vector
* @param v2 the second vector
*/
public void cross(Vec3D v1, Vec3D v2) {
double x, y;
x = v1.y*v2.z-v1.z*v2.y;
y = v2.x*v1.z-v2.z*v1.x;
this.z = v1.x*v2.y-v1.y*v2.x;
this.x = x;
this.y = y;
}
/**
* Sets this vector to the multiplication of vector v1 and a scalar number
* @param v1 the vector
* @param number to multiply v1
*/
public void multiply(Vec3D v1, double number) {
this.x = v1.x*number;
this.y = v1.y*number;
this.z = v1.z*number;
}
/**
* Normalizes this vector in place.
*/
public final void normalize() {
double norm = this.x*this.x+this.y*this.y+this.z*this.z;
if(norm<Util.defaultNumericalPrecision) {
return; // vector is zero
}
if(norm==1) {
return; // often doesn't happen due to roundoff
}
norm = 1/Math.sqrt(norm); // expensive operation
this.x *= norm;
this.y *= norm;
this.z *= norm;
}
/**
* Returns the dot product of this vector and vector v1.
* @param v1 the other vector
* @return the dot product of this and v1
*/
public final double dot(Vec3D v1) {
return(this.x*v1.x+this.y*v1.y+this.z*v1.z);
}
/**
* Returns the squared magnitude of this vector.
* @return the squared magnitude
*/
public final double magnitudeSquared() {
return(this.x*this.x+this.y*this.y+this.z*this.z);
}
/**
* Returns the magnitude of this vector.
* @return the magnitude
*/
public final double magnitude() {
return Math.sqrt(this.x*this.x+this.y*this.y+this.z*this.z);
}
/**
* Returns the angle in radians between this vector and the vector
* parameter; the return value is constrained to the range [0,PI].
* @param v1 the other vector
* @return the angle in radians in the range [0,PI]
*/
public final double angle(Vec3D v1) {
double vDot = this.dot(v1)/(this.magnitude()*v1.magnitude());
if(vDot<-1.0) {
vDot = -1.0;
}
if(vDot>1.0) {
vDot = 1.0;
}
return((Math.acos(vDot)));
}
}
/*
* Open Source Physics software is free software; you can redistribute
* it and/or modify it under the terms of the GNU General Public License (GPL) as
* published by the Free Software Foundation; either version 2 of the License,
* or(at your option) any later version.
* Code that uses any portion of the code in the org.opensourcephysics package
* or any subpackage (subdirectory) of this package must must also be be released
* under the GNU GPL license.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston MA 02111-1307 USA
* or view the license online at http://www.gnu.org/copyleft/gpl.html
*
* Copyright (c) 2007 The Open Source Physics project
* http://www.opensourcephysics.org
*/