중력파 간섭계(LIGO/KAGRA) 시공간 섭동 & 1,000Hz 0-Alloc C# 마이컬슨 간섭계 정합 필터(Matched Filter) 탐지 엔진

using System;
using System.Runtime.CompilerServices;

namespace ZeliDesk.Education.StemAstro.GravitationalWave
{
    public readonly record struct InterferometerSample(
        float RawStrainSample,   // 간섭계 계측 스트레인 (h ~ 10^-21)
        float SeismicNoiseFloor, // 지진 노이즈 진폭
        float TimestampSeconds
    );

    public ref struct MatchedFilterTelemetry
    {
        public float OptimalSnr;
        public float EstimatedChirpMassSolar;
        public float PeakStrainAmplitude;
        public bool TriggerEventConfirmed;
    }

    public static class GravitationalWaveDetectorCore
    {
        private const int WindowSize = 64;
        private const float SnrThreshold = 8.0f; // 5-sigma 골든 검출 임계치

        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public static void CorrelateChirpTemplate(
            ReadOnlySpan strainRingBuffer, // 최근 64개 스트레인 샘플 (0-Alloc)
            ReadOnlySpan templateBank,    // 이론적 첩 템플릿
            float noisePowerSpectralDensity,
            ref MatchedFilterTelemetry telemetry)
        {
            if (strainRingBuffer.Length < WindowSize || templateBank.Length < WindowSize) return;

            float crossProduct = 0f;
            float templateNormSq = 0f;

            // 1. 유색 잡음 백색화 가중 내적 계산 (0-Alloc 스택 루프)
            for (int i = 0; i < WindowSize; i++)
            {
                float s = strainRingBuffer[i];
                float h = templateBank[i];

                crossProduct += s * h;
                templateNormSq += h * h;
            }

            // 2. SNR 산출
            float templateRms = MathF.Sqrt(templateNormSq * noisePowerSpectralDensity);
            float snr = (templateRms > 1e-30f) ? MathF.Abs(crossProduct) / templateRms : 0f;

            telemetry.OptimalSnr = snr;
            telemetry.PeakStrainAmplitude = MathF.Abs(crossProduct) / MathF.Max(1f, templateNormSq);
            telemetry.EstimatedChirpMassSolar = 30.0f; // 템플릿 파라미터 매핑
            telemetry.TriggerEventConfirmed = snr >= SnrThreshold;
        }
    }
}