Vector3

Defines a 3D vector class with operators.

All class functions are defined inline.

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Class Summary

class Vector3

{

public:

	// define real type.
typedef float	real;

	// Constructors.
	Vector3() ;
	Vector3(const real& nx, const real& ny, const real& nz) ;
	Vector3(const real x[3]) ;
	Vector3(const double x[3]) ;

	// Inspection.
Vector3	position() const ;
real	x() const ;
real	x(const unsigned short coord) const ;
bool	isZero() const ;
real	norm() const ;
real	norm2() const ;
real	dist(const Vector3& p) const ;
real	dist2(const Vector3& p) const ;
const real&	operator[](const unsigned short coord) const ;
Vector3	getPerpendicularVector() const ;
Vector3	getUnitVector() const ;

	// Operators.
bool	operator==(const Vector3& v) const ;
friend Vector3	operator+(const Vector3& p1, const Vector3& p2) ;
friend Vector3	operator-(const Vector3& p1, const Vector3& p2) ;
friend Vector3	operator-(const Vector3& p) ;
friend real	operator*(const Vector3& p1, const Vector3& p2) ;
friend Vector3	operator*(const Vector3& p, const real& m) ;
friend Vector3	operator*(const real& m, const Vector3& p) ;
friend Vector3	operator/(const Vector3& p, const real& m) ;
friend Vector3	operator&(const Vector3& p1, const Vector3& p2) ;
friend real	operator\|(const Vector3& p1, const Vector3& p2) ;
friend real	operator^(const Vector3& p1, const Vector3& p2) ;
Vector3&	operator+=(const Vector3& p) ;
Vector3&	operator-=(const Vector3& p) ;
Vector3&	operator*=(const real& m) ;
Vector3&	operator/=(const real& m) ;
friend ostream&	operator<<(ostream& s, const Vector3& v) ;
friend istream&	operator>>(istream& s, Vector3& v) ;
void	output(FILE* outputFile) const ;
protected:

}; // Vector3

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AUTHORS

Meir Fuchs. (meirfux@math.tau.ac.il)

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CHANGES LOG

23/08/2004 - Oranit Dror:
Adding the '==' operator and the 'getPerpendicularVector' and 'getUnitVector' methods

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GOALS

Since most of the work on protein structure is done in 3D space, a fast, well designed 3D vector class was in place. Knowing the dimension is 3 allows for a fast, loopless implemetation of Vector3 and Matrix3 to be written.

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USAGE

Many 3D vector operations are supplied including vector addition and subtraction, dot-product mult., multiplication by scalar, distance and angular operators.

A new Vector3 may be constructed using 3 floats or an array of 3 floats.

    Vector3 v(1.0, 2.0, 3.0);
    float x[3];
    Vector3 v(x);

Coordinates may be accessed using the x(int) method which returns the vector's given coordinate (1..3) or using the [] operator (0..2).

    if (v[0] == v.x(1))  cout << "OK\n";

Addition, subtraction, multiplication and division by scalar, dot-product distance, angle.

    w = u+v;                           // addition
    w-= v;                             // in-place subtraction w==u
    if ((w|u) == 0) cout << "OK\n";    // distance operator |
    if (w^u == 0) cout << "OK\n";      // angle operator ^
    w=2*w;                             // multiplicatio by scalar
    float f=w*v;                       // dot-product;

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typedef float real;

Defines the type with which coordinates are defined. Changing this to double will casue the Vector3 and Matrix3 classes to work with double precision coordinates. float was chosen for considerations of speed. double precision is rarely needed since strctural data is inexact.

  typedef float real;

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