b612
044f2f4381
- 新增半解析、旧模型、自定义与多源堆叠星历实例，提供 Context、Instance、SPK 读取及状态与视位置计算 - 统一太阳、月球和行星实例接口，扩展黄经穿越、留、相位、最近角距、偕日可见、任意高度升落、轨道节点及凌日等天象查询 - 完善日月食、月掩与凌日的月缘剖面、有限盘面接触、站心修正、局地可见性、全球路径和地图输出 - 新增 SVG、GeoJSON、KML 天象输出及凌日、月掩和月缘地形相关缓存与几何求解 - 新增恒星星表导入与查询，支持 CSV、Hipparcos、BSC5、Stellarium 等格式及名称、交叉标识、锥面检索和星等过滤 - 补充 IAU 2006、地球定向、折射消光、大气观测、轨道传播及半解析行星/月球数据支持 - 将默认未来民用时标切换为 TimeScaleLeapHour，更新 2027–2400 农历速查表、中文日期解析和时区边界处理 - 增加事件基线、跨模型回归、几何边界、月缘地形和输出契约测试，完善中英文手册、示例资源、NOTICE 与忽略规则
170 lines
7.8 KiB
Go
170 lines
7.8 KiB
Go
package eclipse
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import (
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"math"
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"time"
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"b612.me/astro/basic"
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"b612.me/astro/internal/geodata"
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)
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const (
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// brownLunationEpochJDE 是布朗月序数 0 号朔的儒略日（1923-01-17）。
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brownLunationEpochJDE = 2423436.0
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// brownLunationSynodicMonth 是平均朔望月长度，用于把朔的儒略日换算成月序数。
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brownLunationSynodicMonth = 29.530588853
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// 视半径换算地平视差用的半径比：地球赤道半径除以天体半径。
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horizontalParallaxMoonRatio = geodata.EarthWGS84RadiusKM / 1737.4
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horizontalParallaxSunRatio = geodata.EarthWGS84RadiusKM / 696000.0
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)
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// SolarEclipseGeocentricPanel 详细面板所需的食甚时刻地心量 / geocentric quantities at greatest eclipse for detailed panels.
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type SolarEclipseGeocentricPanel struct {
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// Conjunction 地心视黄经相等的朔时刻 / new moon at equal geocentric apparent ecliptic longitude.
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Conjunction time.Time
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ConjunctionJDE float64
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// RightAscensionConjunction 地心视赤经相等的时刻，与朔的时差不固定 / equal geocentric apparent right ascension, with a variable gap from new moon.
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RightAscensionConjunction time.Time
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RightAscensionConjunctionJDE float64
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// RightAscensionConjunctionJD 同一合时刻的 UT1 儒略日 / UT1 Julian day of the same conjunction.
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RightAscensionConjunctionJD float64
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// DeltaTSeconds 食甚时刻实际使用的 ΔT / ΔT used at greatest eclipse.
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DeltaTSeconds float64
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// SunRadiusModel SunSemidiameterArcsec 所用的太阳半径口径 / solar radius convention behind SunSemidiameterArcsec.
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SunRadiusModel SolarEclipseSunRadiusModel
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SunRightAscensionDeg float64
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SunDeclinationDeg float64
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SunSemidiameterArcsec float64
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SunParallaxArcsec float64
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MoonRightAscensionDeg float64
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MoonDeclinationDeg float64
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MoonSemidiameterArcsec float64
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MoonParallaxArcsec float64
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LibrationLongitudeDeg float64
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LibrationLatitudeDeg float64
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LibrationPositionAngleDeg float64
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BrownLunationNumber int
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// PenumbralK 与 UmbralK 是月地半径比 k1/k2。
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// PenumbralK and UmbralK are the Moon-to-Earth radius ratios k1 and k2.
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PenumbralK float64
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UmbralK float64
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// BodyShiftLongitudeArcsec 与 BodyShiftLatitudeArcsec 是星历表里的 Δl/Δb；本库模型不做月面位置平移，恒为零。
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// BodyShiftLongitudeArcsec and BodyShiftLatitudeArcsec are the Δl/Δb of published element tables;
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// this model shifts nothing on the lunar surface, so both stay zero.
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BodyShiftLongitudeArcsec float64
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BodyShiftLatitudeArcsec float64
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// Ephemeris 是所用模型名称。
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// Ephemeris names the model in use.
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Ephemeris string
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// SingleK 表示使用的是 IAU Single-K（k1 同时用于半影与本影）。
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// SingleK reports the IAU Single-K convention, where k1 serves both the penumbra and the umbra.
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SingleK bool
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}
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// horizontalParallaxArcsec 由视半径换算地平视差：sin(HP) = sin(SD) × R⊕ / R天体。
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func horizontalParallaxArcsec(semidiameterArcsec, radiusRatio float64) float64 {
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sine := math.Sin(semidiameterArcsec / 3600 * math.Pi / 180)
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return math.Asin(math.Max(-1, math.Min(1, sine*radiusRatio))) * 180 / math.Pi * 3600
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}
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// SolarEclipseGeocentricPanelAt 计算给定日食在食甚时刻的地心量面板 / geocentric solar eclipse panel at greatest eclipse.
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func (module *Eclipse) SolarEclipseGeocentricPanelAt(date time.Time) (SolarEclipseGeocentricPanel, bool) {
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return module.SolarEclipseGeocentricPanelWithOptions(date, SolarEclipseOptions{RadiusModel: SolarEclipseModelNASABulletinSplitK})
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}
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// SolarEclipseGeocentricPanelIAUSingleK 使用 IAU Single-K 计算地心量面板 / geocentric solar eclipse panel with IAU Single-K.
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func (module *Eclipse) SolarEclipseGeocentricPanelIAUSingleK(date time.Time) (SolarEclipseGeocentricPanel, bool) {
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return module.SolarEclipseGeocentricPanelWithOptions(date, SolarEclipseOptions{RadiusModel: SolarEclipseModelIAUSingleK})
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}
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// SolarEclipseGeocentricPanelWithOptions 使用自定义半径口径计算食甚时刻的地心量面板 / geocentric solar eclipse panel with custom radius options.
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func (module *Eclipse) SolarEclipseGeocentricPanelWithOptions(date time.Time, options SolarEclipseOptions) (SolarEclipseGeocentricPanel, bool) {
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info, ok := module.SolarEclipseOnDateWithOptions(date, options)
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if !ok {
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return SolarEclipseGeocentricPanel{}, false
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}
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panel := solarEclipseGeocentricPanelAt(info, module)
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if info.Model == SolarEclipseModelIAUSingleK {
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panel.Ephemeris = "IAU Single-K"
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panel.PenumbralK = basic.SolarEclipseIAUSingleRadiusK
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panel.UmbralK = basic.SolarEclipseIAUSingleRadiusK
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panel.SingleK = true
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return panel, true
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}
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panel.Ephemeris = "NASA bulletin Split-K"
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panel.PenumbralK = basic.SolarEclipsePenumbralK
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panel.UmbralK = basic.SolarEclipseUmbralK
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return panel, true
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}
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func solarEclipseGeocentricPanelAt(info SolarEclipseInfo, modules ...*Eclipse) SolarEclipseGeocentricPanel {
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module := &defaultModule
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if len(modules) > 0 {
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module = modules[0]
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}
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tt := solarEclipseTimeToTTJDE(info.GreatestEclipse)
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conjunctionJDE := basic.CalcMoonSHByJDEWithInstance(tt, 0, module.inst)
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rightAscensionJDE := solarEclipseRightAscensionConjunction(tt, module)
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panel := SolarEclipseGeocentricPanel{
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Conjunction: solarEclipseTTJDEToTime(conjunctionJDE, info.GreatestEclipse.Location()),
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ConjunctionJDE: conjunctionJDE,
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RightAscensionConjunction: solarEclipseTTJDEToTime(rightAscensionJDE, info.GreatestEclipse.Location()),
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RightAscensionConjunctionJDE: rightAscensionJDE,
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RightAscensionConjunctionJD: rightAscensionJDE - basic.DeltaT(tt, true)/86400,
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DeltaTSeconds: basic.DeltaT(tt, true),
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}
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panel.SunRightAscensionDeg, panel.SunDeclinationDeg = basic.SunApparentRaDecWithInstance(tt, module.inst)
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panel.MoonRightAscensionDeg, panel.MoonDeclinationDeg = basic.HMoonTrueRaDecWithInstance(tt, module.inst)
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panel.SunRadiusModel = info.SunRadiusModel
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panel.SunSemidiameterArcsec = basic.SolarEclipseSunSemidiameterWithInstance(tt, info.SunRadiusModel, module.inst)
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panel.MoonSemidiameterArcsec = basic.MoonSemidiameterWithInstance(tt, module.inst)
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panel.SunParallaxArcsec = horizontalParallaxArcsec(panel.SunSemidiameterArcsec, horizontalParallaxSunRatio)
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panel.MoonParallaxArcsec = horizontalParallaxArcsec(panel.MoonSemidiameterArcsec, horizontalParallaxMoonRatio)
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physical := basic.MoonPhysicalWithInstance(tt, module.inst)
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panel.LibrationLongitudeDeg = physical.LibrationLongitude
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panel.LibrationLatitudeDeg = physical.LibrationLatitude
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panel.LibrationPositionAngleDeg = physical.PositionAngle
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panel.BrownLunationNumber = int(math.Floor((panel.ConjunctionJDE-brownLunationEpochJDE)/brownLunationSynodicMonth)) + 1
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return panel
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}
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// solarEclipseRightAscensionGap 返回月亮与太阳的地心视赤经差，单位弧度。
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func solarEclipseRightAscensionGap(tt float64, modules ...*Eclipse) float64 {
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module := &defaultModule
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if len(modules) > 0 {
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module = modules[0]
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}
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sunRightAscension, _ := basic.SunApparentRaDecWithInstance(tt, module.inst)
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moonRightAscension, _ := basic.HMoonTrueRaDecWithInstance(tt, module.inst)
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return math.Remainder(moonRightAscension-sunRightAscension, 360) * math.Pi / 180
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}
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// solarEclipseRightAscensionConjunction 求地心视赤经相等的时刻。
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// 赤经差在合附近单调，用牛顿法从食甚时刻收敛即可，不需要预先求朔。
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func solarEclipseRightAscensionConjunction(tt float64, modules ...*Eclipse) float64 {
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module := &defaultModule
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if len(modules) > 0 {
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module = modules[0]
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}
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estimate := tt
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for iteration := 0; iteration < 40; iteration++ {
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value := solarEclipseRightAscensionGap(estimate, module)
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if math.Abs(value) < 1e-10 {
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break
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}
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derivative := (solarEclipseRightAscensionGap(estimate+1e-5, module) - solarEclipseRightAscensionGap(estimate-1e-5, module)) / 2e-5
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if derivative == 0 || math.IsNaN(derivative) || math.IsInf(derivative, 0) {
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break
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}
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estimate -= value / derivative
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}
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return estimate
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}
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