Implement fast quaternion implementation, minor changes to complex

This commit is contained in:
Iaroslav Postovalov 2020-10-27 18:06:27 +07:00
parent 457931dd86
commit 76717c49b1
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3 changed files with 328 additions and 37 deletions

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@ -8,6 +8,7 @@
- Automatic README generation for features (#139)
- Native support for `memory`, `core` and `dimensions`
- `kmath-ejml` to supply EJML SimpleMatrix wrapper.
- Basic Quaternion vector support.
### Changed
- Package changed from `scientifik` to `kscience.kmath`.

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@ -42,22 +42,21 @@ private val PI_DIV_2 = Complex(PI / 2, 0)
* A field of [Complex].
*/
public object ComplexField : ExtendedField<Complex>, Norm<Complex, Complex> {
override val zero: Complex = 0.0.toComplex()
override val one: Complex = 1.0.toComplex()
override val zero: Complex by lazy { 0.toComplex() }
override val one: Complex by lazy { 1.toComplex() }
/**
* The imaginary unit.
*/
public val i: Complex = Complex(0.0, 1.0)
public val i: Complex by lazy { Complex(0, 1) }
override fun add(a: Complex, b: Complex): Complex = Complex(a.re + b.re, a.im + b.im)
public override fun add(a: Complex, b: Complex): Complex = Complex(a.re + b.re, a.im + b.im)
public override fun multiply(a: Complex, k: Number): Complex = Complex(a.re * k.toDouble(), a.im * k.toDouble())
override fun multiply(a: Complex, k: Number): Complex = Complex(a.re * k.toDouble(), a.im * k.toDouble())
override fun multiply(a: Complex, b: Complex): Complex =
public override fun multiply(a: Complex, b: Complex): Complex =
Complex(a.re * b.re - a.im * b.im, a.re * b.im + a.im * b.re)
override fun divide(a: Complex, b: Complex): Complex = when {
public override fun divide(a: Complex, b: Complex): Complex = when {
b.re.isNaN() || b.im.isNaN() -> Complex(Double.NaN, Double.NaN)
(if (b.im < 0) -b.im else +b.im) < (if (b.re < 0) -b.re else +b.re) -> {
@ -83,31 +82,31 @@ public object ComplexField : ExtendedField<Complex>, Norm<Complex, Complex> {
}
}
override fun sin(arg: Complex): Complex = i * (exp(-i * arg) - exp(i * arg)) / 2
override fun cos(arg: Complex): Complex = (exp(-i * arg) + exp(i * arg)) / 2
public override fun sin(arg: Complex): Complex = i * (exp(-i * arg) - exp(i * arg)) / 2
public override fun cos(arg: Complex): Complex = (exp(-i * arg) + exp(i * arg)) / 2
override fun tan(arg: Complex): Complex {
public override fun tan(arg: Complex): Complex {
val e1 = exp(-i * arg)
val e2 = exp(i * arg)
return i * (e1 - e2) / (e1 + e2)
}
override fun asin(arg: Complex): Complex = -i * ln(sqrt(1 - (arg * arg)) + i * arg)
override fun acos(arg: Complex): Complex = PI_DIV_2 + i * ln(sqrt(1 - (arg * arg)) + i * arg)
public override fun asin(arg: Complex): Complex = -i * ln(sqrt(1 - (arg * arg)) + i * arg)
public override fun acos(arg: Complex): Complex = PI_DIV_2 + i * ln(sqrt(1 - (arg * arg)) + i * arg)
override fun atan(arg: Complex): Complex {
public override fun atan(arg: Complex): Complex {
val iArg = i * arg
return i * (ln(1 - iArg) - ln(1 + iArg)) / 2
}
override fun power(arg: Complex, pow: Number): Complex = if (arg.im == 0.0)
public override fun power(arg: Complex, pow: Number): Complex = if (arg.im == 0.0)
arg.re.pow(pow.toDouble()).toComplex()
else
exp(pow * ln(arg))
override fun exp(arg: Complex): Complex = exp(arg.re) * (cos(arg.im) + i * sin(arg.im))
public override fun exp(arg: Complex): Complex = exp(arg.re) * (cos(arg.im) + i * sin(arg.im))
override fun ln(arg: Complex): Complex = ln(arg.r) + i * atan2(arg.im, arg.re)
public override fun ln(arg: Complex): Complex = ln(arg.r) + i * atan2(arg.im, arg.re)
/**
* Adds complex number to real one.
@ -116,7 +115,7 @@ public object ComplexField : ExtendedField<Complex>, Norm<Complex, Complex> {
* @param c the augend.
* @return the sum.
*/
public operator fun Double.plus(c: Complex): Complex = add(this.toComplex(), c)
public operator fun Double.plus(c: Complex): Complex = add(toComplex(), c)
/**
* Subtracts complex number from real one.
@ -125,7 +124,7 @@ public object ComplexField : ExtendedField<Complex>, Norm<Complex, Complex> {
* @param c the subtrahend.
* @return the difference.
*/
public operator fun Double.minus(c: Complex): Complex = add(this.toComplex(), -c)
public operator fun Double.minus(c: Complex): Complex = add(toComplex(), -c)
/**
* Adds real number to complex one.
@ -154,9 +153,9 @@ public object ComplexField : ExtendedField<Complex>, Norm<Complex, Complex> {
*/
public operator fun Double.times(c: Complex): Complex = Complex(c.re * this, c.im * this)
override fun norm(arg: Complex): Complex = sqrt(arg.conjugate * arg)
override fun symbol(value: String): Complex = if (value == "i") i else super.symbol(value)
public override fun Complex.unaryMinus(): Complex = Complex(-re, -im)
public override fun norm(arg: Complex): Complex = sqrt(arg.conjugate * arg)
public override fun symbol(value: String): Complex = if (value == "i") i else super.symbol(value)
}
/**
@ -169,26 +168,23 @@ public data class Complex(val re: Double, val im: Double) : FieldElement<Complex
Comparable<Complex> {
public constructor(re: Number, im: Number) : this(re.toDouble(), im.toDouble())
override val context: ComplexField get() = ComplexField
override fun unwrap(): Complex = this
override fun Complex.wrap(): Complex = this
override fun compareTo(other: Complex): Int = r.compareTo(other.r)
override fun toString(): String {
return "($re + i*$im)"
}
public override val context: ComplexField
get() = ComplexField
public override fun unwrap(): Complex = this
public override fun Complex.wrap(): Complex = this
public override fun compareTo(other: Complex): Int = r.compareTo(other.r)
public override fun toString(): String = "($re + $im * i)"
public override fun minus(b: Complex): Complex = Complex(re - b.re, im - b.im)
public companion object : MemorySpec<Complex> {
override val objectSize: Int
public override val objectSize: Int
get() = 16
override fun MemoryReader.read(offset: Int): Complex = Complex(readDouble(offset), readDouble(offset + 8))
public override fun MemoryReader.read(offset: Int): Complex =
Complex(readDouble(offset), readDouble(offset + 8))
override fun MemoryWriter.write(offset: Int, value: Complex) {
public override fun MemoryWriter.write(offset: Int, value: Complex) {
writeDouble(offset, value.re)
writeDouble(offset + 8, value.im)
}
@ -201,7 +197,7 @@ public data class Complex(val re: Double, val im: Double) : FieldElement<Complex
* @receiver the real part.
* @return the new complex number.
*/
public fun Number.toComplex(): Complex = Complex(this, 0.0)
public fun Number.toComplex(): Complex = Complex(this, 0)
/**
* Creates a new buffer of complex numbers with the specified [size], where each element is calculated by calling the

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@ -0,0 +1,294 @@
package kscience.kmath.operations
import kscience.kmath.memory.MemoryReader
import kscience.kmath.memory.MemorySpec
import kscience.kmath.memory.MemoryWriter
import kscience.kmath.structures.Buffer
import kscience.kmath.structures.MemoryBuffer
import kscience.kmath.structures.MutableBuffer
import kscience.kmath.structures.MutableMemoryBuffer
import kotlin.math.*
/**
* This quaternion's conjugate.
*/
public val Quaternion.conjugate: Quaternion
get() = QuaternionField { z - x * i - y * j - z * k }
/**
* This quaternion's reciprocal.
*/
public val Quaternion.reciprocal: Quaternion
get() {
val n = QuaternionField { norm(this@reciprocal) }
return conjugate / (n * n)
}
/**
* Absolute value of the quaternion.
*/
public val Quaternion.r: Double
get() = sqrt(w * w + x * x + y * y + z * z)
/**
* A field of [Quaternion].
*/
public object QuaternionField : Field<Quaternion>, Norm<Quaternion, Quaternion>, PowerOperations<Quaternion>,
ExponentialOperations<Quaternion> {
override val zero: Quaternion by lazy { 0.toQuaternion() }
override val one: Quaternion by lazy { 1.toQuaternion() }
/**
* The `i` quaternion unit.
*/
public val i: Quaternion by lazy { Quaternion(0, 1, 0, 0) }
/**
* The `j` quaternion unit.
*/
public val j: Quaternion by lazy { Quaternion(0, 0, 1, 0) }
/**
* The `k` quaternion unit.
*/
public val k: Quaternion by lazy { Quaternion(0, 0, 0, 1) }
public override fun add(a: Quaternion, b: Quaternion): Quaternion =
Quaternion(a.w + b.w, a.x + b.x, a.y + b.y, a.z + b.z)
public override fun multiply(a: Quaternion, k: Number): Quaternion {
val d = k.toDouble()
return Quaternion(a.w * d, a.x * d, a.y * d, a.z * d)
}
public override fun multiply(a: Quaternion, b: Quaternion): Quaternion = Quaternion(
a.w * b.w - a.x * b.x - a.y * b.y - a.z * b.z,
a.w * b.x + a.x * b.w + a.y * b.z - a.z * b.y,
a.w * b.y - a.x * b.z + a.y * b.w + a.z * b.x,
a.w * b.z + a.x * b.y - a.y * b.x + a.z * b.w,
)
override fun divide(a: Quaternion, b: Quaternion): Quaternion {
val s = b.w * b.w + b.x * b.x + b.y * b.y + b.z * b.z
return Quaternion(
(b.w * a.w + b.x * a.x + b.y * a.y + b.z * a.z) / s,
(b.w * a.x - b.x * a.w - b.y * a.z + b.z * a.y) / s,
(b.w * a.y + b.x * a.z - b.y * a.w - b.z * a.x) / s,
(b.w * a.z - b.x * a.y + b.y * a.x - b.z * a.w) / s,
)
}
public override fun power(arg: Quaternion, pow: Number): Quaternion {
if (pow is Int) return pwr(arg, pow)
if (floor(pow.toDouble()) == pow.toDouble()) return pwr(arg, pow.toInt())
return exp(pow * ln(arg))
}
private fun pwr(x: Quaternion, a: Int): Quaternion {
if (a < 0) return -(pwr(x, -a))
if (a == 0) return one
if (a == 1) return x
if (a == 2) return pwr2(x)
if (a == 3) return pwr3(x)
if (a == 4) return pwr4(x)
val x4 = pwr4(x)
var y = x4
repeat((1 until a / 4).count()) { y *= x4 }
if (a % 4 == 3) y *= pwr3(x)
if (a % 4 == 2) y *= pwr2(x)
if (a % 4 == 1) y *= x
return y
}
private inline fun pwr2(x: Quaternion): Quaternion {
val aa = 2 * x.w
return Quaternion(
x.w * x.w - (x.x * x.x + x.y * x.y + x.z * x.z),
aa * x.x,
aa * x.y,
aa * x.z
)
}
private inline fun pwr3(x: Quaternion): Quaternion {
val a2 = x.w * x.w
val n1 = x.x * x.x + x.y * x.y + x.z * x.z
val n2 = 3.0 * a2 - n1
return Quaternion(
x.w * (a2 - 3 * n1),
x.x * n2,
x.y * n2,
x.z * n2
)
}
private inline fun pwr4(x: Quaternion): Quaternion {
val a2 = x.w * x.w
val n1 = x.x * x.x + x.y * x.y + x.z * x.z
val n2 = 4 * x.w * (a2 - n1)
return Quaternion(
a2 * a2 - 6 * a2 * n1 + n1 * n1,
x.x * n2,
x.y * n2,
x.z * n2
)
}
public override fun exp(arg: Quaternion): Quaternion {
val un = arg.x * arg.x + arg.y * arg.y + arg.z * arg.z
if (un == 0.0) return exp(arg.w).toQuaternion()
val n1 = sqrt(un)
val ea = exp(arg.w)
val n2 = ea * sin(n1) / n1
return Quaternion(ea * cos(n1), n2 * arg.x, n2 * arg.y, n2 * arg.z)
}
public override fun ln(arg: Quaternion): Quaternion {
val nu2 = arg.x * arg.x + arg.y * arg.y + arg.z * arg.z
if (nu2 == 0.0)
return if (arg.w > 0)
Quaternion(ln(arg.w), 0, 0, 0)
else {
val l = ComplexField { ln(arg.w.toComplex()) }
Quaternion(l.re, l.im, 0, 0)
}
val a = arg.w
check(nu2 > 0)
val n = sqrt(a * a + nu2)
val th = acos(a / n) / sqrt(nu2)
return Quaternion(ln(n), th * arg.x, th * arg.y, th * arg.z)
}
/**
* Adds quaternion to real one.
*
* @receiver the addend.
* @param c the augend.
* @return the sum.
*/
public operator fun Double.plus(c: Quaternion): Quaternion = Quaternion(this + c.w, c.x, c.y, c.z)
/**
* Subtracts quaternion from real one.
*
* @receiver the minuend.
* @param c the subtrahend.
* @return the difference.
*/
public operator fun Double.minus(c: Quaternion): Quaternion = Quaternion(this - c.w, -c.x, -c.y, -c.z)
/**
* Adds real number to quaternion.
*
* @receiver the addend.
* @param d the augend.
* @return the sum.
*/
public operator fun Quaternion.plus(d: Double): Quaternion = Quaternion(w + d, x, y, z)
/**
* Subtracts real number from quaternion.
*
* @receiver the minuend.
* @param d the subtrahend.
* @return the difference.
*/
public operator fun Quaternion.minus(d: Double): Quaternion = Quaternion(w - d, x, y, z)
/**
* Multiplies real number by quaternion.
*
* @receiver the multiplier.
* @param c the multiplicand.
* @receiver the product.
*/
public operator fun Double.times(c: Quaternion): Quaternion =
Quaternion(this * c.w, this * c.x, this * c.y, this * c.z)
public override fun Quaternion.unaryMinus(): Quaternion = Quaternion(-w, -x, -y, -z)
public override fun norm(arg: Quaternion): Quaternion = sqrt(arg.conjugate * arg)
public override fun symbol(value: String): Quaternion = when (value) {
"i" -> i
"j" -> j
"k" -> k
else -> super<Field>.symbol(value)
}
}
/**
* Represents `double`-based quaternion.
*
* @property w The first component.
* @property x The second component.
* @property y The third component.
* @property z The fourth component.
*/
public data class Quaternion(val w: Double, val x: Double, val y: Double, val z: Double) :
FieldElement<Quaternion, Quaternion, QuaternionField>,
Comparable<Quaternion> {
public constructor(w: Number, x: Number, y: Number, z: Number) : this(
w.toDouble(),
x.toDouble(),
y.toDouble(),
z.toDouble()
)
public constructor(wx: Complex, yz: Complex) : this(wx.re, wx.im, yz.re, yz.im)
public override val context: QuaternionField
get() = QuaternionField
public override fun div(k: Number): Quaternion {
val d = k.toDouble()
return Quaternion(w / d, x / d, y / d, z / d)
}
public override fun unwrap(): Quaternion = this
public override fun Quaternion.wrap(): Quaternion = this
public override fun compareTo(other: Quaternion): Int = r.compareTo(other.r)
public override fun toString(): String = "($w + $x * i + $y * j + $z * k)"
public companion object : MemorySpec<Quaternion> {
public override val objectSize: Int
get() = 32
public override fun MemoryReader.read(offset: Int): Quaternion =
Quaternion(readDouble(offset), readDouble(offset + 8), readDouble(offset + 16), readDouble(offset + 24))
public override fun MemoryWriter.write(offset: Int, value: Quaternion) {
writeDouble(offset, value.w)
writeDouble(offset + 8, value.x)
writeDouble(offset + 16, value.y)
writeDouble(offset + 24, value.z)
}
}
}
/**
* Creates a quaternion with real part equal to this real.
*
* @receiver the real part.
* @return the new quaternion.
*/
public fun Number.toQuaternion(): Quaternion = Quaternion(this, 0, 0, 0)
/**
* Creates a new buffer of quaternions with the specified [size], where each element is calculated by calling the
* specified [init] function.
*/
public inline fun Buffer.Companion.quaternion(size: Int, init: (Int) -> Quaternion): Buffer<Quaternion> =
MemoryBuffer.create(Quaternion, size, init)
/**
* Creates a new buffer of quaternions with the specified [size], where each element is calculated by calling the
* specified [init] function.
*/
public inline fun MutableBuffer.Companion.quaternion(size: Int, init: (Int) -> Quaternion): MutableBuffer<Quaternion> =
MutableMemoryBuffer.create(Quaternion, size, init)