Files
Miha Kralj 7253f61299 Add TRAMA implementation and comprehensive tests
- Implemented the TRAMA (Trend Regularity Adaptive Moving Average) class with adaptive EMA logic.
- Added unit tests for TRAMA functionality, including constructor validation, basic calculations, state management, and robustness checks.
- Created validation tests to ensure consistency across different modes of operation (streaming, batch, and static calculations).
- Enhanced documentation for TRAMA, including performance profiles and quality metrics.
- Updated workspace configuration by removing unnecessary folder references.
2026-02-21 20:45:38 -08:00

419 lines
12 KiB
C#

using System.Buffers;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
namespace QuanTAlib;
/// <summary>
/// KAISER: Kaiser Window Moving Average
/// </summary>
/// <remarks>
/// Symmetric FIR filter using the Kaiser-Bessel window function for optimal
/// sidelobe attenuation. The beta parameter continuously controls the trade-off
/// between main lobe width (transition band sharpness) and sidelobe attenuation.
///
/// Calculation: Precomputed weights via modified Bessel function I0, applied as
/// FIR convolution over sliding window. Beta=0 gives SMA, beta≈5.65 Blackman,
/// beta≈8.6 Hamming.
/// </remarks>
/// <seealso href="Kaiser.md">Detailed documentation</seealso>
[SkipLocalsInit]
public sealed class Kaiser : AbstractBase
{
private readonly int _period;
private readonly double _beta;
private readonly double[] _weights;
private readonly RingBuffer _buffer;
private readonly ITValuePublisher? _source;
private readonly TValuePublishedHandler? _pubHandler;
private bool _isNew = true;
private bool _disposed;
private double _lastValidValue = double.NaN;
private double _p_lastValidValue = double.NaN;
public bool IsNew => _isNew;
public override bool IsHot => _buffer.IsFull;
/// <summary>
/// Creates KAISER with specified period and beta.
/// </summary>
/// <param name="period">Lookback period (>= 2)</param>
/// <param name="beta">Shape parameter controlling sidelobe attenuation (0..20, default 3.0)</param>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public Kaiser(int period = 14, double beta = 3.0)
{
if (period < 2)
{
throw new ArgumentException("Period must be at least 2", nameof(period));
}
if (beta < 0)
{
throw new ArgumentException("Beta must be non-negative", nameof(beta));
}
_period = period;
_beta = beta;
Name = $"Kaiser({_period},{_beta:F1})";
WarmupPeriod = _period;
_buffer = new RingBuffer(_period);
_weights = new double[_period];
ComputeKaiserWeights(_weights, _period, _beta);
}
/// <summary>
/// Creates KAISER connected to a data source for event-based updates.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public Kaiser(ITValuePublisher source, int period = 14, double beta = 3.0) : this(period, beta)
{
_source = source;
_pubHandler = Handle;
_source.Pub += _pubHandler;
}
/// <summary>
/// Modified Bessel function of the first kind, order 0.
/// 25-term power series: I0(x) = sum_{m=0}^{25} [(x/2)^m / m!]^2
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static double BesselI0(double x)
{
double sum = 1.0;
double term = 1.0;
double halfX = x * 0.5;
for (int m = 1; m <= 25; m++)
{
term *= halfX / m;
sum += term * term;
}
return sum;
}
/// <summary>
/// Computes Kaiser window weights and normalizes to sum=1.
/// w(k) = I0(beta * sqrt(1 - t^2)) / I0(beta), where t = 2k/(N-1) - 1.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static void ComputeKaiserWeights(Span<double> weights, int period, double beta)
{
double i0Beta = BesselI0(beta);
double nm1 = period - 1;
double wsum = 0.0;
for (int k = 0; k < period; k++)
{
double t = nm1 > 0 ? (2.0 * k / nm1) - 1.0 : 0.0;
double argSq = 1.0 - t * t;
double arg = argSq > 0 ? Math.Sqrt(argSq) : 0.0;
double w = i0Beta > 0 ? BesselI0(beta * arg) / i0Beta : 1.0;
weights[k] = w;
wsum += w;
}
if (Math.Abs(wsum) > double.Epsilon)
{
double inv = 1.0 / wsum;
for (int k = 0; k < period; k++)
{
weights[k] *= inv;
}
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public override TValue Update(TValue input, bool isNew = true)
{
_isNew = isNew;
return Update(input, isNew, publish: true);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private TValue Update(TValue input, bool isNew, bool publish)
{
if (isNew)
{
_p_lastValidValue = _lastValidValue;
}
else
{
_lastValidValue = _p_lastValidValue;
}
double val = GetValidValue(input.Value);
if (!double.IsFinite(val))
{
Last = new TValue(input.Time, double.NaN);
if (publish) { PubEvent(Last, isNew); }
return Last;
}
if (isNew)
{
_lastValidValue = val;
_buffer.Add(val);
int count = _buffer.Count;
double result;
if (count < _period)
{
result = val;
}
else
{
result = ConvolveFull(_buffer, _weights);
}
Last = new TValue(input.Time, result);
if (publish) { PubEvent(Last, isNew); }
return Last;
}
else
{
_buffer.Snapshot();
double prevLast = _lastValidValue;
double prevPLast = _p_lastValidValue;
_lastValidValue = val;
_buffer.UpdateNewest(val);
int count = _buffer.Count;
double result;
if (count < _period)
{
result = val;
}
else
{
result = ConvolveFull(_buffer, _weights);
}
Last = new TValue(input.Time, result);
_buffer.Restore();
_lastValidValue = prevLast;
_p_lastValidValue = prevPLast;
if (publish) { PubEvent(Last, isNew); }
return Last;
}
}
public override TSeries Update(TSeries source)
{
if (source.Count == 0)
{
return new TSeries([], []);
}
int len = source.Count;
var t = new List<long>(len);
var v = new List<double>(len);
CollectionsMarshal.SetCount(t, len);
CollectionsMarshal.SetCount(v, len);
var tSpan = CollectionsMarshal.AsSpan(t);
var vSpan = CollectionsMarshal.AsSpan(v);
Batch(source.Values, vSpan, _period, _beta);
source.Times.CopyTo(tSpan);
Reset();
int startIndex = Math.Max(0, len - _period);
for (int i = startIndex; i < len; i++)
{
Update(source[i], isNew: true, publish: false);
}
return new TSeries(t, v);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private void Handle(object? sender, in TValueEventArgs e) => Update(e.Value, e.IsNew);
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private double GetValidValue(double input)
{
if (double.IsFinite(input))
{
return input;
}
return double.IsFinite(_lastValidValue) ? _lastValidValue : double.NaN;
}
/// <summary>
/// FIR convolution using SIMD DotProduct over circular buffer.
/// Weight[0] corresponds to oldest bar, Weight[period-1] to newest.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static double ConvolveFull(RingBuffer buffer, double[] weights)
{
ReadOnlySpan<double> internalBuf = buffer.InternalBuffer;
int head = buffer.StartIndex;
int period = buffer.Capacity;
int part1Len = period - head;
double sum1 = internalBuf.Slice(head, part1Len).DotProduct(weights.AsSpan(0, part1Len));
double sum2 = internalBuf[..head].DotProduct(weights.AsSpan(part1Len));
return sum1 + sum2;
}
public override void Prime(ReadOnlySpan<double> source, TimeSpan? step = null)
{
foreach (var value in source)
{
Update(new TValue(DateTime.MinValue, value));
}
}
public static TSeries Batch(TSeries source, int period = 14, double beta = 3.0)
{
var kaiser = new Kaiser(period, beta);
return kaiser.Update(source);
}
/// <summary>
/// Calculates Kaiser Window MA over a span of values.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static void Batch(ReadOnlySpan<double> source, Span<double> output, int period = 14, double beta = 3.0, double nanValue = double.NaN)
{
if (period < 2)
{
throw new ArgumentException("Period must be at least 2", nameof(period));
}
if (source.Length != output.Length)
{
throw new ArgumentException("Source and output must have the same length", nameof(output));
}
if (source.Length == 0)
{
return;
}
int len = source.Length;
const int StackallocThreshold = 256;
double[]? weightsRented = period > StackallocThreshold ? ArrayPool<double>.Shared.Rent(period) : null;
Span<double> weights = period <= StackallocThreshold
? stackalloc double[period]
: weightsRented!.AsSpan(0, period);
double[]? ringRented = period > StackallocThreshold ? ArrayPool<double>.Shared.Rent(period) : null;
Span<double> ring = period <= StackallocThreshold
? stackalloc double[period]
: ringRented!.AsSpan(0, period);
double[]? cleanRented = len > StackallocThreshold ? ArrayPool<double>.Shared.Rent(len) : null;
Span<double> clean = len <= StackallocThreshold
? stackalloc double[len]
: cleanRented!.AsSpan(0, len);
ComputeKaiserWeights(weights, period, beta);
try
{
double lastValid = nanValue;
for (int i = 0; i < len; i++)
{
double val = source[i];
if (double.IsFinite(val))
{
lastValid = val;
clean[i] = val;
}
else if (double.IsFinite(lastValid))
{
clean[i] = lastValid;
}
else
{
clean[i] = double.NaN;
}
}
int ringIdx = 0;
int count = 0;
for (int i = 0; i < len; i++)
{
double val = clean[i];
ring[ringIdx] = val;
ringIdx++;
if (ringIdx >= period)
{
ringIdx = 0;
}
if (count < period)
{
count++;
}
if (count < period)
{
output[i] = val;
continue;
}
int part1Len = period - ringIdx;
ReadOnlySpan<double> ringRo = ring;
double sum = ringRo.Slice(ringIdx, part1Len).DotProduct(weights.Slice(0, part1Len))
+ ringRo[..ringIdx].DotProduct(weights.Slice(part1Len));
output[i] = sum;
}
}
finally
{
if (weightsRented != null)
{
ArrayPool<double>.Shared.Return(weightsRented);
}
if (ringRented != null)
{
ArrayPool<double>.Shared.Return(ringRented);
}
if (cleanRented != null)
{
ArrayPool<double>.Shared.Return(cleanRented);
}
}
}
public static (TSeries Results, Kaiser Indicator) Calculate(TSeries source, int period = 14, double beta = 3.0)
{
var indicator = new Kaiser(period, beta);
TSeries results = indicator.Update(source);
return (results, indicator);
}
public override void Reset()
{
_buffer.Clear();
_lastValidValue = double.NaN;
_p_lastValidValue = double.NaN;
Last = default;
}
protected override void Dispose(bool disposing)
{
if (!_disposed)
{
if (disposing && _source != null && _pubHandler != null)
{
_source.Pub -= _pubHandler;
}
_disposed = true;
}
base.Dispose(disposing);
}
}