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QuanTAlib/lib/oscillators/fisher/Fisher.Validation.Tests.cs
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2026-02-26 22:02:52 -08:00

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C#

using OoplesFinance.StockIndicators;
using OoplesFinance.StockIndicators.Models;
using System.Runtime.CompilerServices;
using Tulip;
using Xunit;
using Xunit.Abstractions;
namespace QuanTAlib.Tests;
/// <summary>
/// Validates Fisher Transform against Tulip NETCore and manual computation.
/// Tulip's fisher indicator uses the same normalization + arctanh approach.
/// </summary>
public sealed class FisherValidationTests(ITestOutputHelper output) : IDisposable
{
private readonly ValidationTestData _testData = new();
private readonly ITestOutputHelper _output = output;
private bool _disposed;
private const int TestPeriod = 10;
public void Dispose()
{
Dispose(disposing: true);
}
private void Dispose(bool disposing)
{
if (_disposed) { return; }
_disposed = true;
if (disposing) { _testData?.Dispose(); }
}
#region Manual arctanh Cross-Validation
[Fact]
[SkipLocalsInit]
public void Validate_Against_Manual_Arctanh()
{
// Validate that our Fisher Transform correctly computes arctanh
// by testing with known normalized inputs
double[] testValues = [-0.9, -0.5, 0.0, 0.5, 0.9];
foreach (double v in testValues)
{
double expected = 0.5 * Math.Log((1.0 + v) / (1.0 - v));
double actual = Math.Atanh(v);
Assert.True(Math.Abs(expected - actual) < 1e-12,
$"arctanh({v}): expected={expected}, actual={actual}");
}
_output.WriteLine("arctanh mathematical identity verified.");
}
[Fact]
[SkipLocalsInit]
public void Validate_Against_Manual_Computation()
{
double[] values = _testData.RawData.ToArray();
int[] periods = [5, 10, 20];
foreach (int period in periods)
{
double[] batchOutput = new double[values.Length];
Fisher.Batch(values.AsSpan(), batchOutput.AsSpan(), period);
// Manual computation
double[] manualOutput = new double[values.Length];
double emaValue = 0.0;
var buffer = new double[period];
int bufCount = 0;
int bufIdx = 0;
for (int i = 0; i < values.Length; i++)
{
double val = values[i];
// Add to circular buffer
if (bufCount < period)
{
buffer[bufCount] = val;
bufCount++;
}
else
{
buffer[bufIdx] = val;
bufIdx = (bufIdx + 1) % period;
}
// Find min/max
double highest = double.MinValue;
double lowest = double.MaxValue;
for (int j = 0; j < bufCount; j++)
{
if (buffer[j] > highest)
{
highest = buffer[j];
}
if (buffer[j] < lowest)
{
lowest = buffer[j];
}
}
double range = highest - lowest;
double normalized = range > 0.0
? 2.0 * ((val - lowest) / range) - 1.0
: 0.0;
emaValue = 0.33 * normalized + 0.67 * emaValue;
double clamped = Math.Clamp(emaValue, -0.999, 0.999);
manualOutput[i] = 0.5 * Math.Log((1.0 + clamped) / (1.0 - clamped));
}
int validCount = 0;
for (int i = period; i < values.Length; i++)
{
Assert.True(Math.Abs(manualOutput[i] - batchOutput[i]) < 1e-9,
$"Fisher mismatch at i={i}, period={period}: manual={manualOutput[i]}, batch={batchOutput[i]}");
validCount++;
}
Assert.True(validCount > 0, $"No valid comparison points for period {period}");
_output.WriteLine($"Fisher period={period}: validated {validCount} points against manual computation.");
}
}
[Theory]
[InlineData(5)]
[InlineData(10)]
[InlineData(20)]
[InlineData(50)]
public void Validate_Manual_DifferentPeriods(int period)
{
double[] values = _testData.RawData.ToArray();
double[] batchOutput = new double[values.Length];
Fisher.Batch(values.AsSpan(), batchOutput.AsSpan(), period);
// Verify all outputs are finite
for (int i = 0; i < values.Length; i++)
{
Assert.True(double.IsFinite(batchOutput[i]),
$"Fisher output not finite at i={i}, period={period}: {batchOutput[i]}");
}
_output.WriteLine($"Fisher period={period}: all {values.Length} outputs finite.");
}
#endregion
#region Consistency Validation
[Fact]
[SkipLocalsInit]
public void Validate_Streaming_Batch_Span_Agree()
{
double[] tData = _testData.RawData.ToArray();
// Batch TSeries
TSeries batchSeries = Fisher.Batch(_testData.Data, TestPeriod);
// Batch Span
var spanOutput = new double[tData.Length];
Fisher.Batch(tData.AsSpan(), spanOutput.AsSpan(), TestPeriod);
// Batch and Span should be identical (same code path)
for (int i = 0; i < tData.Length; i++)
{
Assert.Equal(batchSeries.Values[i], spanOutput[i], 12);
}
// Streaming
var fisher = new Fisher(TestPeriod);
var streamResults = new double[tData.Length];
for (int i = 0; i < tData.Length; i++)
{
streamResults[i] = fisher.Update(_testData.Data[i]).Value;
}
// Streaming vs Batch should match exactly (same algorithm, same state)
for (int i = 0; i < tData.Length; i++)
{
Assert.Equal(streamResults[i], batchSeries.Values[i], 9);
}
_output.WriteLine("Fisher streaming/batch/span agreement verified.");
}
#endregion
#region Tulip Cross-Validation
/// <summary>
/// Structural validation against Tulip <c>fisher</c> indicator.
/// Algorithm variant: Tulip fisher uses two inputs (high[], low[]) and computes the
/// Fisher Transform from the high-low price range midpoint normalized over a rolling window.
/// QuanTAlib Fisher uses a single price series with EMA-based normalization via alpha parameter.
/// Direct numeric equality is not asserted; both must produce finite output on the same data.
/// </summary>
[Fact]
public void Fisher_Tulip_StructuralVariant_BothFinite()
{
const int period = 10;
double[] highData = _testData.HighPrices.ToArray();
double[] lowData = _testData.LowPrices.ToArray();
// Tulip fisher — uses high/low range normalization
var tulipIndicator = Tulip.Indicators.fisher;
double[][] inputs = { highData, lowData };
double[] options = { period };
int lookback = tulipIndicator.Start(options);
double[][] outputs = { new double[highData.Length - lookback], new double[highData.Length - lookback] };
tulipIndicator.Run(inputs, options, outputs);
double[] tResult = outputs[0];
// QuanTAlib Fisher — single price series (close)
var fisher = new Fisher(TestPeriod);
foreach (var item in _testData.Data) { fisher.Update(item); }
// Structural: Tulip must produce finite output
Assert.True(tResult.Length > 0, "Tulip fisher must produce output");
foreach (double v in tResult)
{
Assert.True(double.IsFinite(v), $"Tulip fisher produced non-finite value: {v}");
}
// QuanTAlib must also be hot and finite
Assert.True(fisher.IsHot, "QuanTAlib Fisher must be hot after sufficient bars");
Assert.True(double.IsFinite(fisher.Last.Value), "QuanTAlib Fisher last value must be finite");
}
[Fact]
[SkipLocalsInit]
public void Validate_Event_Matches_Streaming()
{
// Streaming
var streamFisher = new Fisher(TestPeriod);
var streamResults = new double[_testData.Data.Count];
for (int i = 0; i < _testData.Data.Count; i++)
{
streamResults[i] = streamFisher.Update(_testData.Data[i]).Value;
}
// Event-based
var eventSource = new TSeries();
var eventFisher = new Fisher(eventSource, TestPeriod);
var eventResults = new double[_testData.Data.Count];
for (int i = 0; i < _testData.Data.Count; i++)
{
eventSource.Add(_testData.Data[i]);
eventResults[i] = eventFisher.Last.Value;
}
for (int i = 0; i < _testData.Data.Count; i++)
{
Assert.Equal(streamResults[i], eventResults[i], 12);
}
_output.WriteLine("Fisher event-based matches streaming.");
}
#endregion
#region Ooples Validation
/// <summary>
/// Structural validation against Ooples <c>CalculateEhlersFisherTransform</c>.
/// Ooples uses the Ehlers variant: HL2 (high-low midpoint) normalized over rolling period,
/// then arctanh transformed. QuanTAlib Fisher uses a single price series with EMA-based
/// normalization via alpha parameter. Input types differ (OHLCV vs close-only); numeric
/// equality not asserted. Both must produce finite output on the same underlying data.
/// </summary>
[Fact]
public void Fisher_Ooples_StructuralVariant_BothFinite()
{
var ooplesData = _testData.SkenderQuotes.Select(q => new TickerData
{
Date = q.Date,
Open = (double)q.Open,
High = (double)q.High,
Low = (double)q.Low,
Close = (double)q.Close,
Volume = (double)q.Volume
}).ToList();
var stockData = new StockData(ooplesData);
var oResult = stockData.CalculateEhlersFisherTransform(length: TestPeriod);
var oValues = oResult.OutputValues.Values.First();
// QuanTAlib Fisher — single price series (close)
var fisher = new Fisher(TestPeriod);
foreach (var item in _testData.Data) { fisher.Update(item); }
// Structural: Ooples must produce finite output
Assert.True(oValues.Count > 0, "Ooples Fisher must produce output");
int finiteCount = 0;
for (int i = TestPeriod; i < oValues.Count; i++)
{
if (double.IsFinite(oValues[i])) { finiteCount++; }
}
Assert.True(finiteCount > 100, $"Expected >100 finite Ooples values, got {finiteCount}");
Assert.True(fisher.IsHot, "QuanTAlib Fisher must be hot after sufficient bars");
Assert.True(double.IsFinite(fisher.Last.Value), "QuanTAlib Fisher last value must be finite");
_output.WriteLine($"Fisher Ooples structural: {finiteCount} finite Ooples values, QuanTAlib last={fisher.Last.Value:F6}");
}
#endregion
}