68 lines
1.3 KiB
Go
68 lines
1.3 KiB
Go
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package planets
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import (
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_ "embed"
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"sync"
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)
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// 现代段为 J2000 ± 1000 儒略年。
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const (
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ModernStart = 2086295.0
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ModernEnd = 2816795.0
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)
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var (
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//go:embed long.bin
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longTable []byte
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//go:embed modern.bin
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modernTable []byte
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)
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var (
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defaultOnce sync.Once
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defaultModel *Model
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)
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// Default 内置长时段表叠加现代段，首次调用时解析 / built-in long-range plus modern tables, parsed on first use.
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func Default() *Model {
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defaultOnce.Do(func() {
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m, err := Parse(longTable)
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if err == nil {
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err = m.WithModernSegment(modernTable, ModernStart, ModernEnd)
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}
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if err != nil {
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panic(err)
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}
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defaultModel = m
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})
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return defaultModel
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}
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// GM 天体号 1..8 的 GM 与太阳 GM，au³/日²；EMB 为地月合计，越界返回 0 / GM of body id and of the Sun, au³/day².
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func GM(id int) (body, sun float64) {
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if id < 1 || id > 8 {
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return 0, gmSol
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}
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return gmp[id-1], gmSol
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}
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//go:embed fast.bin
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var fastTable []byte
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var (
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fastOnce sync.Once
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fastModel *Model
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)
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// Fast 快速档表（n ≥ 0 用），首次调用时解析 / the fast-tier table used for n ≥ 0, parsed on first use.
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func Fast() *Model {
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fastOnce.Do(func() {
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m, err := Parse(fastTable)
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if err != nil {
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panic(err)
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}
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fastModel = m
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})
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return fastModel
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}
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