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astro/planet/internal/semianalytic/apparent_generic_test.go
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package semianalytic
import (
"math"
"testing"
"b612.me/astro/internal/ephem"
)
// stateOnly 只暴露几何状态,迫使实例走通用矢量链。
type stateOnly struct{ Ephemeris }
func (e stateOnly) State(t, c ephem.Body, jd float64) ([3]float64, [3]float64, error) {
return e.Ephemeris.State(t, c, jd)
}
func (e stateOnly) Coverage(t ephem.Body) (float64, float64, bool) { return e.Ephemeris.Coverage(t) }
func TestGenericApparentMatchesNative(t *testing.T) {
inst := ephem.NewInstance(stateOnly{})
worst := 0.0
for _, jd := range []float64{2451545.0, 2460409.25, 2433282.5, 2488069.5} {
for _, b := range []ephem.Body{ephem.Sun, ephem.Moon, ephem.Mercury, ephem.Venus, ephem.Mars, ephem.Jupiter, ephem.Saturn, ephem.Uranus, ephem.Neptune} {
want, wd, _, err := Ephemeris{}.Apparent(b, jd)
if err != nil {
t.Fatal(err)
}
got, gd, _, err := inst.Apparent(b, jd)
if err != nil {
t.Fatalf("body %d: %v", b, err)
}
cx := got[1]*want[2] - got[2]*want[1]
cy := got[2]*want[0] - got[0]*want[2]
cz := got[0]*want[1] - got[1]*want[0]
c := got[0]*want[0] + got[1]*want[1] + got[2]*want[2]
// acos 在 1 附近每 ulp 约 3 mas,用 atan2 避开这一噪声底。
arcsec := math.Atan2(math.Sqrt(cx*cx+cy*cy+cz*cz), c) * 206264.806
worst = math.Max(worst, arcsec)
// 原生链的太阳质心速度只计四颗巨行星,与通用链差到数 mas。
if arcsec > 0.005 || math.Abs(gd-wd)/wd > 1e-9 {
t.Errorf("jd %.1f body %d: direction %.5f\" dist %.3f km", jd, b, arcsec, gd-wd)
}
}
}
t.Logf("worst %.6f\"", worst)
}