ofMatrix3x3file

ofMatrix3x3class

A 3x3 Matrix.

The layout is like this:

[ a b c ]
[ d e f ]
[ g h i ]

Constructor

ofMatrix3x3 ()

ofMatrix3x3(float _a=0.0, float _b=0.0, float _c=0.0, float _d=0.0, float _e=0.0, float _f=0.0, float _g=0.0, float _h=0.0, float _i=0.0)

Matrix access

set ()

void set(float _a, float _b, float _c, float _d, float _e, float _f, float _g, float _h, float _i)

operator[] ()

float & operator[](const int &index)

Functions

transpose ()

void transpose()

Transpose the matrix.

This changes the matrix.

[ a b c ]T    [ a d g ]
[ d e f ]  =  [ b e h ]
[ g h i ]     [ c f i ]

ofMatrix3x3 transpose(const ofMatrix3x3 &A)

Transpose without changing the matrix. Uses the "swap" method with additions and subtractions to swap the elements that aren't on the main diagonal.

Returns: transposed matrix.

determinant ()

float determinant() const

Find the determinant of the matrix.

See Also: Wolfram explanation

float determinant(const ofMatrix3x3 &A)

inverse ()

ofMatrix3x3 inverse(const ofMatrix3x3 &A)

Inverse of a 3x3 matrix.

the inverse is the adjoint divided through the determinant find the matrix of minors (minor = determinant of 2x2 matrix of the 2 rows/colums current element is NOT in) turn them in cofactors (= change some of the signs) find the adjoint by transposing the matrix of cofactors divide this through the determinant to get the inverse

See Also: invert();

invert ()

void invert()

entrywiseTimes ()

ofMatrix3x3 entrywiseTimes(const ofMatrix3x3 &A)

Multiply a matrix by a matrix entry by entry (i.e. a*a, b*b, c*c...)

This is referred to as an entrywise, Hadamard, or Schur product

Operators

operator+ ()

ofMatrix3x3 operator+(const ofMatrix3x3 &B)

Add two matrices.

operator+= ()

void operator+=(const ofMatrix3x3 &B)

Add matrix to existing matrix.

operator- ()

ofMatrix3x3 operator-(const ofMatrix3x3 &B)

Subtract two matrices.

operator-= ()

void operator-=(const ofMatrix3x3 &B)

Subtract matrix from existing matrix.

operator* ()

ofMatrix3x3 operator*(float scalar)

Multiply a matrix with a scalar.

operator*= ()

void operator*=(const ofMatrix3x3 &B)

Multiply a matrix by a matrix this = this*B (in that order)

void operator*=(float scalar)

Multiply a matrix by a scalar (multiples all entries by scalar)

operator* ()

ofMatrix3x3 operator*(const ofMatrix3x3 &B)

Multiply a 3x3 matrix with a 3x3 matrix.

operator/ ()

ofMatrix3x3 operator/(float scalar)

Divide a matrix through a scalar.

operator/= ()

void operator/=(const ofMatrix3x3 &B)

void operator/=(float scalar)

operator<< friend

friend ostream & operator<<(ostream &os, const ofMatrix3x3 &M)

operator>> friend

friend istream & operator>>(istream &is, ofMatrix3x3 &M)

Attributes

a variable

float a

b variable

float b

c variable

float c

d variable

float d

e variable

float e

f variable

float f

g variable

float g

h variable

float h

i variable

float i