hmi.math
Class SpatialVec

java.lang.Object
  hmi.math.SpatialVec

public final class SpatialVec
extends Object

A collection of methods for spatial vectors As defined in Rigid Body Dynamics Algorithms Roy Featherstone 2007 Spatial vectors can be stored within arrays of length 6, or they can be stored inside a larger float array a, together with an integer offset "index" into that array. This represents a vector with components (a[index], a[index+1], a[index+2]). The methods from this class never allocate new arrays; rather, they assume that results are to be stored into some existing "destination" array.

Author:

Herwin van Welbergen

Field Summary

static int	SPATIALVEC_SIZE Length of SpatialVec arrays is 6
static float[]	ZERO The zero vector

Constructor Summary

private

SpatialVec()

Method Summary

static void	add(float[] dst, float[] a) dst = dst+a
static void	add(float[] dst, float[] a, float[] b) dst = a+b
static void	add(float[] dst, int dstIndex, float[] a, int aIndex) dst = dst+a
static void	cross(float[] dst, float[] a, float[] b) Cross product
static void	cross(float[] dst, int dstIndex, float[] a, int aIndex, float[] b, int bIndex) velocity x velocity product
static void	crossForce(float[] dst, float[] v, float[] f) movement x force, Featherstone's x* operation
static void	crossForce(float[] dst, int dstIndex, float[] v, int vIndex, float[] f, int fIndex) movement x force, Featherstone's x* operation
static float	dot(float[] a, float[] b) Spatial dot product
static float	dot(float[] a, int aIndex, float[] b, int bIndex) Spatial dot product
static boolean	epsilonEquals(float[] a, float[] b, float epsilon) Tests for equality of vector components within epsilon.
static boolean	epsilonEquals(float[] a, int aIndex, float[] b, int bIndex, float epsilon) Tests for equality of vector components within epsilon.
static void	set(float[] dst, float[] src) Copies the src 6-vector to the dst 6-vector
static void	set(float[] dst, float[] w, float[] v0) Sets the dst 6-vector from two 3-vectors dst=[w v0]^T
static void	set(float[] dst, float v0, float v1, float v2, float v3, float v4, float v5) Copies the src 6-vector to the dst 6-vector
static void	set(float[] dst, int dstIndex, float[] src, int srcIndex) Copies the src 6-vector to the dst 6-vector
static void	setAcc(float[] dst, float[] w, float[] v, float[] wDiff, float[] a) Set the spatial acceleration vector from 'traditional' angular velocity, velocity, angular acceleration and acceleration
static void	setZero(float[] dst)
static void	sub(float[] dst, float[] a) dst = dst-a
static void	sub(float[] dst, float[] a, float[] b) dst = a-b
static void	sub(float[] dst, int dstIndex, float[] a, int aIndex) dst = dst-a
static String	toString(float[] a) String representation
static String	toString(float[] a, int aIndex) String representation

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SPATIALVEC_SIZE

public static final int SPATIALVEC_SIZE

Length of SpatialVec arrays is 6

See Also:

Constant Field Values

ZERO

public static final float[] ZERO

The zero vector

Constructor Detail

SpatialVec

private SpatialVec()

Method Detail

set

public static void set(float[] dst,
                       float v0,
                       float v1,
                       float v2,
                       float v3,
                       float v4,
                       float v5)

Copies the src 6-vector to the dst 6-vector

setZero

public static void setZero(float[] dst)

set

public static void set(float[] dst,
                       float[] src)

Copies the src 6-vector to the dst 6-vector

set

public static void set(float[] dst,
                       int dstIndex,
                       float[] src,
                       int srcIndex)

Copies the src 6-vector to the dst 6-vector

set

public static void set(float[] dst,
                       float[] w,
                       float[] v0)

Sets the dst 6-vector from two 3-vectors dst=[w v0]^T

setAcc

public static void setAcc(float[] dst,
                          float[] w,
                          float[] v,
                          float[] wDiff,
                          float[] a)

Set the spatial acceleration vector from 'traditional' angular velocity, velocity, angular acceleration and acceleration

add

public static void add(float[] dst,
                       float[] a,
                       float[] b)

dst = a+b

sub

public static void sub(float[] dst,
                       float[] a,
                       float[] b)

dst = a-b

add

public static void add(float[] dst,
                       float[] a)

dst = dst+a

sub

public static void sub(float[] dst,
                       float[] a)

dst = dst-a

add

public static void add(float[] dst,
                       int dstIndex,
                       float[] a,
                       int aIndex)

dst = dst+a

sub

public static void sub(float[] dst,
                       int dstIndex,
                       float[] a,
                       int aIndex)

dst = dst-a

dot

public static float dot(float[] a,
                        float[] b)

Spatial dot product

dot

public static float dot(float[] a,
                        int aIndex,
                        float[] b,
                        int bIndex)

Spatial dot product

cross

public static void cross(float[] dst,
                         float[] a,
                         float[] b)

Cross product

cross

public static void cross(float[] dst,
                         int dstIndex,
                         float[] a,
                         int aIndex,
                         float[] b,
                         int bIndex)

velocity x velocity product

crossForce

public static void crossForce(float[] dst,
                              float[] v,
                              float[] f)

movement x force, Featherstone's x* operation

crossForce

public static void crossForce(float[] dst,
                              int dstIndex,
                              float[] v,
                              int vIndex,
                              float[] f,
                              int fIndex)

movement x force, Featherstone's x* operation

epsilonEquals

public static boolean epsilonEquals(float[] a,
                                    float[] b,
                                    float epsilon)

Tests for equality of vector components within epsilon.

epsilonEquals

public static boolean epsilonEquals(float[] a,
                                    int aIndex,
                                    float[] b,
                                    int bIndex,
                                    float epsilon)

Tests for equality of vector components within epsilon.

toString

public static String toString(float[] a)

String representation

toString

public static String toString(float[] a,
                              int aIndex)

String representation