README
¶
geom a package for 3D Euclidean geometry
Overview
This package provides routines for managing 3D vectors and matrices and their various transformations.
API
The API provided by this package is avalble using go doc zappem.net/pub/math/geom. It can also be browsed on the
go.dev website:
package zappem.net/pub/math/geom.
License info
The geom package is distributed with the same BSD 3-clause license as that used by golang itself.
Reporting bugs
Use the github geom bug tracker.
Documentation
¶
Overview ¶
Package geom implements matrix math for 3D vectors and matrices.
Index ¶
- Variables
- func DefineZeroish(z float64)
- func RefZero() float64
- func Zeroish(a float64) bool
- type Angle
- type Matrix
- func (m Matrix) Add(n Matrix) Matrix
- func (m Matrix) AddS(n Matrix, s float64) Matrix
- func (m Matrix) Det() float64
- func (m Matrix) Eigen() (s float64, v Vector, a Angle, err error)
- func (m Matrix) Equals(n Matrix) bool
- func (m Matrix) Inv() (Matrix, error)
- func (m Matrix) Scale(s float64) Matrix
- func (m Matrix) Sub(n Matrix) Matrix
- func (m Matrix) Transpose() Matrix
- func (m Matrix) X() Vector
- func (m Matrix) XM(n Matrix) Matrix
- func (m Matrix) XV(v Vector) Vector
- func (m Matrix) Y() Vector
- func (m Matrix) Z() Vector
- type Vector
- func (v Vector) Add(u Vector) Vector
- func (v Vector) AddS(u Vector, s float64) Vector
- func (v Vector) Cross(u Vector) Vector
- func (v Vector) Dot(u Vector) float64
- func (v Vector) Equals(u Vector) bool
- func (v Vector) NonCollinear() (u Vector, err error)
- func (v Vector) Normalize() (u Vector, err error)
- func (v Vector) R() float64
- func (v Vector) RV(a Angle) (m Matrix, err error)
- func (v Vector) Scale(s float64) Vector
- func (v Vector) Sub(u Vector) Vector
Constants ¶
This section is empty.
Variables ¶
var ( ErrNormalNotPossible = errors.New("normal not possible") ErrNotValidMatrix = errors.New("not a 3x3 matrix") ErrSingular = errors.New("too close to singular") ErrNoNormalForZeroVector = errors.New("no non-collinear of zero vector") ErrIsIdentity = errors.New("too close to identity") )
ErrNormalNotPossible etc are errors returned by this package.
var I = M(1)
I is the identity matrix.
var ZeroM = M()
ZeroM is the zero matrix.
var ZeroV = V()
ZeroV is a zero vector.
Functions ¶
func DefineZeroish ¶
func DefineZeroish(z float64)
DefineZeroish sets the zeroEnough scale. It should be called with a positive value to have any effect. If called with zero or a negative number, it prevents the Zeroish() funcion from recognizing near zero. Zeroish defaults to treating 10^-7 as close enough to zero.
Types ¶
type Angle ¶
type Angle float64
Angle represents an angle.
func (Angle) LikeTan ¶
LikeTan returns an angle that is 180 degrees opposed to a. If a is non-positive, we add 180 deg, otherwise, we subtract 180 deg.
type Matrix ¶
type Matrix []float64
Matrix is a square 3x3 matrix type.
func M ¶
M defines a matrix. It takes a variable number of arguments, if the number of arguments is:
1 - create a matrix with this value used by the elements on the
trace.
3 - create a matrix with these values used to fill the trace elements.
9 - each element is specified, left to right, top to bottom.
other - start filling at [0][0], walking rows left to right until
out of elements.
func (Matrix) Eigen ¶
Eigen decomposes a matrix into its determinant (s), its eigenvector (v) and an angle (a) which is the positive angle or rotation around v that the matrix represents.
func (Matrix) Inv ¶
Inv returns the inverse of a matrix. We use the Gauss-Jordan method to find the inverse.
type Vector ¶
type Vector []float64
Vector is a column vector with 3 elements.
func (Vector) Cross ¶
Cross returns the cross-product of two vectors. It returns a vector perpendicular to both u and v. It returns v x u using right hand rule.
func (Vector) NonCollinear ¶
NonCollinear returns a vector that is not a scalar multiple of the input.
func (Vector) RV ¶
RV returns a rotation matrix for an angle (a) around vector axis (v). The axis vector (v) need not be of unit length. This function uses the Rodrigues rotation formula.
Source Files