forked from kscience/kmath
Add missing files
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0c6fff3878
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@ -0,0 +1,11 @@
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package kscience.kmath.prob.internal
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import kotlin.math.abs
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internal object InternalErf {
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fun erfc(x: Double): Double {
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if (abs(x) > 40) return if (x > 0) 0.0 else 2.0
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val ret = InternalGamma.regularizedGammaQ(0.5, x * x, 10000)
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return if (x < 0) 2 - ret else ret
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}
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}
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package kscience.kmath.prob.internal
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import kotlin.math.*
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private abstract class ContinuedFraction protected constructor() {
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protected abstract fun getA(n: Int, x: Double): Double
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protected abstract fun getB(n: Int, x: Double): Double
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fun evaluate(x: Double, maxIterations: Int): Double {
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val small = 1e-50
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var hPrev = getA(0, x)
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if (hPrev == 0.0 || abs(0.0 - hPrev) <= small) hPrev = small
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var n = 1
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var dPrev = 0.0
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var cPrev = hPrev
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var hN = hPrev
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while (n < maxIterations) {
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val a = getA(n, x)
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val b = getB(n, x)
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var dN = a + b * dPrev
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if (dN == 0.0 || abs(0.0 - dN) <= small) dN = small
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var cN = a + b / cPrev
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if (cN == 0.0 || abs(0.0 - cN) <= small) cN = small
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dN = 1 / dN
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val deltaN = cN * dN
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hN = hPrev * deltaN
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check(!hN.isInfinite()) { "hN is infinite" }
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check(!hN.isNaN()) { "hN is NaN" }
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if (abs(deltaN - 1.0) < 10e-9) break
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dPrev = dN
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cPrev = cN
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hPrev = hN
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n++
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}
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check(n < maxIterations) { "n is more than maxIterations" }
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return hN
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}
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}
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internal object InternalGamma {
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const val LANCZOS_G = 607.0 / 128.0
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private val LANCZOS = doubleArrayOf(
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0.99999999999999709182,
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57.156235665862923517,
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-59.597960355475491248,
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14.136097974741747174,
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-0.49191381609762019978,
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.33994649984811888699e-4,
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.46523628927048575665e-4,
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-.98374475304879564677e-4,
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.15808870322491248884e-3,
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-.21026444172410488319e-3,
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.21743961811521264320e-3,
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-.16431810653676389022e-3,
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.84418223983852743293e-4,
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-.26190838401581408670e-4,
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.36899182659531622704e-5
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)
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private val HALF_LOG_2_PI = 0.5 * ln(2.0 * PI)
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private const val INV_GAMMA1P_M1_A0 = .611609510448141581788E-08
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private const val INV_GAMMA1P_M1_A1 = .624730830116465516210E-08
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private const val INV_GAMMA1P_M1_B1 = .203610414066806987300E+00
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private const val INV_GAMMA1P_M1_B2 = .266205348428949217746E-01
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private const val INV_GAMMA1P_M1_B3 = .493944979382446875238E-03
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private const val INV_GAMMA1P_M1_B4 = -.851419432440314906588E-05
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private const val INV_GAMMA1P_M1_B5 = -.643045481779353022248E-05
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private const val INV_GAMMA1P_M1_B6 = .992641840672773722196E-06
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private const val INV_GAMMA1P_M1_B7 = -.607761895722825260739E-07
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private const val INV_GAMMA1P_M1_B8 = .195755836614639731882E-09
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private const val INV_GAMMA1P_M1_P0 = .6116095104481415817861E-08
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private const val INV_GAMMA1P_M1_P1 = .6871674113067198736152E-08
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private const val INV_GAMMA1P_M1_P2 = .6820161668496170657918E-09
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private const val INV_GAMMA1P_M1_P3 = .4686843322948848031080E-10
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private const val INV_GAMMA1P_M1_P4 = .1572833027710446286995E-11
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private const val INV_GAMMA1P_M1_P5 = -.1249441572276366213222E-12
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private const val INV_GAMMA1P_M1_P6 = .4343529937408594255178E-14
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private const val INV_GAMMA1P_M1_Q1 = .3056961078365221025009E+00
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private const val INV_GAMMA1P_M1_Q2 = .5464213086042296536016E-01
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private const val INV_GAMMA1P_M1_Q3 = .4956830093825887312020E-02
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private const val INV_GAMMA1P_M1_Q4 = .2692369466186361192876E-03
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private const val INV_GAMMA1P_M1_C = -.422784335098467139393487909917598E+00
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private const val INV_GAMMA1P_M1_C0 = .577215664901532860606512090082402E+00
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private const val INV_GAMMA1P_M1_C1 = -.655878071520253881077019515145390E+00
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private const val INV_GAMMA1P_M1_C2 = -.420026350340952355290039348754298E-01
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private const val INV_GAMMA1P_M1_C3 = .166538611382291489501700795102105E+00
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private const val INV_GAMMA1P_M1_C4 = -.421977345555443367482083012891874E-01
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private const val INV_GAMMA1P_M1_C5 = -.962197152787697356211492167234820E-02
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private const val INV_GAMMA1P_M1_C6 = .721894324666309954239501034044657E-02
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private const val INV_GAMMA1P_M1_C7 = -.116516759185906511211397108401839E-02
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private const val INV_GAMMA1P_M1_C8 = -.215241674114950972815729963053648E-03
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private const val INV_GAMMA1P_M1_C9 = .128050282388116186153198626328164E-03
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private const val INV_GAMMA1P_M1_C10 = -.201348547807882386556893914210218E-04
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private const val INV_GAMMA1P_M1_C11 = -.125049348214267065734535947383309E-05
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private const val INV_GAMMA1P_M1_C12 = .113302723198169588237412962033074E-05
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private const val INV_GAMMA1P_M1_C13 = -.205633841697760710345015413002057E-06
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fun logGamma(x: Double): Double {
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val ret: Double
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when {
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x.isNaN() || x <= 0.0 -> ret = Double.NaN
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x < 0.5 -> return logGamma1p(x) - ln(x)
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x <= 2.5 -> return logGamma1p(x - 0.5 - 0.5)
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x <= 8.0 -> {
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val n = floor(x - 1.5).toInt()
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var prod = 1.0
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(1..n).forEach { i -> prod *= x - i }
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return logGamma1p(x - (n + 1)) + ln(prod)
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}
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else -> {
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val tmp = x + LANCZOS_G + .5
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ret = (x + .5) * ln(tmp) - tmp + HALF_LOG_2_PI + ln(lanczos(x) / x)
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}
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}
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return ret
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}
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private fun regularizedGammaP(
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a: Double,
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x: Double,
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maxIterations: Int = Int.MAX_VALUE
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): Double = when {
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a.isNaN() || x.isNaN() || a <= 0.0 || x < 0.0 -> Double.NaN
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x == 0.0 -> 0.0
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x >= a + 1 -> 1.0 - regularizedGammaQ(a, x, maxIterations)
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else -> {
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// calculate series
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var n = 0.0 // current element index
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var an = 1.0 / a // n-th element in the series
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var sum = an // partial sum
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while (abs(an / sum) > 10e-15 && n < maxIterations && sum < Double.POSITIVE_INFINITY) {
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// compute next element in the series
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n += 1.0
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an *= x / (a + n)
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// update partial sum
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sum += an
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}
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when {
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n >= maxIterations -> throw error("Maximal iterations is exceeded $maxIterations")
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sum.isInfinite() -> 1.0
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else -> exp(-x + a * ln(x) - logGamma(a)) * sum
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}
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}
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}
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fun regularizedGammaQ(
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a: Double,
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x: Double,
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maxIterations: Int = Int.MAX_VALUE
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): Double = when {
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a.isNaN() || x.isNaN() || a <= 0.0 || x < 0.0 -> Double.NaN
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x == 0.0 -> 1.0
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x < a + 1.0 -> 1.0 - regularizedGammaP(a, x, maxIterations)
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else -> 1.0 / object : ContinuedFraction() {
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override fun getA(n: Int, x: Double): Double = 2.0 * n + 1.0 - a + x
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override fun getB(n: Int, x: Double): Double = n * (a - n)
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}.evaluate(x, maxIterations) * exp(-x + a * ln(x) - logGamma(a))
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}
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private fun lanczos(x: Double): Double =
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(LANCZOS.size - 1 downTo 1).sumByDouble { LANCZOS[it] / (x + it) } + LANCZOS[0]
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private fun invGamma1pm1(x: Double): Double {
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require(x >= -0.5)
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require(x <= 1.5)
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val ret: Double
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val t = if (x <= 0.5) x else x - 0.5 - 0.5
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if (t < 0.0) {
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val a = INV_GAMMA1P_M1_A0 + t * INV_GAMMA1P_M1_A1
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var b = INV_GAMMA1P_M1_B8
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b = INV_GAMMA1P_M1_B7 + t * b
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b = INV_GAMMA1P_M1_B6 + t * b
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b = INV_GAMMA1P_M1_B5 + t * b
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b = INV_GAMMA1P_M1_B4 + t * b
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b = INV_GAMMA1P_M1_B3 + t * b
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b = INV_GAMMA1P_M1_B2 + t * b
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b = INV_GAMMA1P_M1_B1 + t * b
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b = 1.0 + t * b
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var c = INV_GAMMA1P_M1_C13 + t * (a / b)
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c = INV_GAMMA1P_M1_C12 + t * c
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c = INV_GAMMA1P_M1_C11 + t * c
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c = INV_GAMMA1P_M1_C10 + t * c
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c = INV_GAMMA1P_M1_C9 + t * c
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c = INV_GAMMA1P_M1_C8 + t * c
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c = INV_GAMMA1P_M1_C7 + t * c
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c = INV_GAMMA1P_M1_C6 + t * c
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c = INV_GAMMA1P_M1_C5 + t * c
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c = INV_GAMMA1P_M1_C4 + t * c
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c = INV_GAMMA1P_M1_C3 + t * c
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c = INV_GAMMA1P_M1_C2 + t * c
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c = INV_GAMMA1P_M1_C1 + t * c
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c = INV_GAMMA1P_M1_C + t * c
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ret = (if (x > 0.5) t * c / x else x * (c + 0.5 + 0.5))
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} else {
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var p = INV_GAMMA1P_M1_P6
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p = INV_GAMMA1P_M1_P5 + t * p
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p = INV_GAMMA1P_M1_P4 + t * p
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p = INV_GAMMA1P_M1_P3 + t * p
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p = INV_GAMMA1P_M1_P2 + t * p
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p = INV_GAMMA1P_M1_P1 + t * p
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p = INV_GAMMA1P_M1_P0 + t * p
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var q = INV_GAMMA1P_M1_Q4
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q = INV_GAMMA1P_M1_Q3 + t * q
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q = INV_GAMMA1P_M1_Q2 + t * q
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q = INV_GAMMA1P_M1_Q1 + t * q
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q = 1.0 + t * q
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var c = INV_GAMMA1P_M1_C13 + p / q * t
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c = INV_GAMMA1P_M1_C12 + t * c
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c = INV_GAMMA1P_M1_C11 + t * c
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c = INV_GAMMA1P_M1_C10 + t * c
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c = INV_GAMMA1P_M1_C9 + t * c
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c = INV_GAMMA1P_M1_C8 + t * c
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c = INV_GAMMA1P_M1_C7 + t * c
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c = INV_GAMMA1P_M1_C6 + t * c
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c = INV_GAMMA1P_M1_C5 + t * c
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c = INV_GAMMA1P_M1_C4 + t * c
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c = INV_GAMMA1P_M1_C3 + t * c
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c = INV_GAMMA1P_M1_C2 + t * c
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c = INV_GAMMA1P_M1_C1 + t * c
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c = INV_GAMMA1P_M1_C0 + t * c
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ret = (if (x > 0.5) t / x * (c - 0.5 - 0.5) else x * c)
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}
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return ret
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}
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private fun logGamma1p(x: Double): Double {
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require(x >= -0.5)
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require(x <= 1.5)
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return -ln1p(invGamma1pm1(x))
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}
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}
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@ -0,0 +1,78 @@
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package kscience.kmath.prob.internal
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import kotlin.math.ln
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import kotlin.math.min
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internal object InternalUtils {
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private val FACTORIALS = longArrayOf(
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1L, 1L, 2L,
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6L, 24L, 120L,
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720L, 5040L, 40320L,
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362880L, 3628800L, 39916800L,
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479001600L, 6227020800L, 87178291200L,
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1307674368000L, 20922789888000L, 355687428096000L,
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6402373705728000L, 121645100408832000L, 2432902008176640000L
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)
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private const val BEGIN_LOG_FACTORIALS = 2
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fun factorial(n: Int): Long = FACTORIALS[n]
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fun validateProbabilities(probabilities: DoubleArray?): Double {
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require(!(probabilities == null || probabilities.isEmpty())) { "Probabilities must not be empty." }
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var sumProb = 0.0
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probabilities.forEach { prob ->
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validateProbability(prob)
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sumProb += prob
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}
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require(!(sumProb.isInfinite() || sumProb <= 0)) { "Invalid sum of probabilities: $sumProb" }
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return sumProb
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}
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private fun validateProbability(probability: Double): Unit =
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require(!(probability < 0 || probability.isInfinite() || probability.isNaN())) { "Invalid probability: $probability" }
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class FactorialLog private constructor(
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numValues: Int,
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cache: DoubleArray?
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) {
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private val logFactorials: DoubleArray = DoubleArray(numValues)
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init {
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val endCopy: Int
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if (cache != null && cache.size > BEGIN_LOG_FACTORIALS) {
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// Copy available values.
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endCopy = min(cache.size, numValues)
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cache.copyInto(
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logFactorials,
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BEGIN_LOG_FACTORIALS,
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BEGIN_LOG_FACTORIALS, endCopy
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)
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}
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// All values to be computed
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else endCopy = BEGIN_LOG_FACTORIALS
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// Compute remaining values.
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(endCopy until numValues).forEach { i ->
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if (i < FACTORIALS.size)
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logFactorials[i] = ln(FACTORIALS[i].toDouble())
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else
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logFactorials[i] = logFactorials[i - 1] + ln(i.toDouble())
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}
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}
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fun value(n: Int): Double {
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if (n < logFactorials.size)
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return logFactorials[n]
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return if (n < FACTORIALS.size) ln(FACTORIALS[n].toDouble()) else InternalGamma.logGamma(n + 1.0)
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}
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companion object {
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fun create(): FactorialLog = FactorialLog(0, null)
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}
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}
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}
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@ -1,31 +0,0 @@
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package scientifik.kmath.prob
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import kscience.kmath.prob.RandomGenerator
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import org.apache.commons.rng.simple.RandomSource
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public class RandomSourceGenerator(private val source: RandomSource, seed: Long?) :
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RandomGenerator {
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private val random = seed?.let {
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RandomSource.create(source, seed)
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} ?: RandomSource.create(source)
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public override fun nextBoolean(): Boolean = random.nextBoolean()
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public override fun nextDouble(): Double = random.nextDouble()
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public override fun nextInt(): Int = random.nextInt()
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public override fun nextInt(until: Int): Int = random.nextInt(until)
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public override fun nextLong(): Long = random.nextLong()
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public override fun nextLong(until: Long): Long = random.nextLong(until)
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public override fun fillBytes(array: ByteArray, fromIndex: Int, toIndex: Int) {
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require(toIndex > fromIndex)
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random.nextBytes(array, fromIndex, toIndex - fromIndex)
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}
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override fun fork(): RandomGenerator = RandomSourceGenerator(source, nextLong())
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}
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public fun RandomGenerator.Companion.fromSource(source: RandomSource, seed: Long? = null): RandomSourceGenerator =
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RandomSourceGenerator(source, seed)
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public fun RandomGenerator.Companion.mersenneTwister(seed: Long? = null): RandomSourceGenerator =
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fromSource(RandomSource.MT, seed)
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