Add DetectSeasonality as a Helper function in TimeSeries ExtensionDialog

[lisahua]

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This PR is part of Feature Request: #5230 : Add Seasonality Detection for Time-Series Data

Description

In time series data, seasonality is the presence of variations that occur at specific regular intervals less than a year, such as weekly, monthly, or quarterly.

In this PR, we propose to provide Seasonality Detection Support for Time-Series Data based on fourier analysis.

• DetectSeasonality API:

        /// <summary>
        /// Obtain the period by adopting techniques of spectral analysis. which is founded by
        /// the fourier analysis. returns -1 means there's no significant period. otherwise, a period
        /// is returned.
        /// </summary>
        /// <param name="catalog">The detect seasonality catalog.</param>
        /// <param name="input">Input DataView.The data is an instance of <see cref="Microsoft.ML.IDataView"/>.</param>
        /// <param name="inputColumnName">Name of column to process. The column data must be <see cref="System.Double"/>.</param>
        /// <param name="seasonalityWindowSize">An upper bound on the largest relevant seasonality in the input time-series.
        /// When set to -1, use the whole input to fit model, when set to a positive integer, use this number as batch size.
        /// Default value is -1.</param>
        /// <returns>The detected period if seasonality period exists, otherwise return -1.</returns>
        public static int DetectSeasonality(this AnomalyDetectionCatalog catalog, IDataView input, string inputColumnName, int seasonalityWindowSize = -1)

This PR introduced:

1. DetectSeasonality API to ExtensionDialog in TimeSeries project
2. Internal class SeasonalityDetector that implements the actual logic based on fourier tranform
3. Sample DetectSeasonality in docs/sample/timeseries folder.
4. Unit Tests in TimeSeriesDirectApi file
5. Change MedianDblAggregator to be BestFriend and use it in SeasonalityDetector

[dnfadmin]

All CLA requirements met. #Resolved

[codecov]

Codecov Report

Merging #5231 into master will decrease coverage by 4.16%.
The diff coverage is 72.94%.

@@            Coverage Diff             @@
##           master    #5231      +/-   ##
==========================================
- Coverage   73.47%   69.30%   -4.17%     
==========================================
  Files        1010      771     -239     
  Lines      187988   145018   -42970     
  Branches    20262    18461    -1801     
==========================================
- Hits       138118   100502   -37616     
+ Misses      44385    39343    -5042     
+ Partials     5485     5173     -312     

Flag	Coverage Δ
#Debug	69.30% <72.94%> (-4.17%)	⬇️
#production	69.30% <72.94%> (+0.01%)	⬆️
#test	?

Impacted Files	Coverage Δ
src/Microsoft.ML.TimeSeries/SeasonalityDetector.cs	71.77% <71.77%> (ø)
...Microsoft.ML.Data/Transforms/NormalizeColumnDbl.cs	70.72% <100.00%> (ø)
src/Microsoft.ML.TimeSeries/ExtensionsCatalog.cs	93.61% <100.00%> (-1.39%)	⬇️
src/Microsoft.ML.AutoML/Utils/BestResultUtil.cs	53.84% <0.00%> (-3.69%)	⬇️
....ML.AutoML/PipelineSuggesters/PipelineSuggester.cs	79.83% <0.00%> (-3.37%)	⬇️
src/Microsoft.ML.TimeSeries/RootCauseAnalyzer.cs	54.20% <0.00%> (-2.25%)	⬇️
...or/CodeGenerator/CSharp/TrainerGeneratorFactory.cs	81.25% <0.00%> (-2.09%)	⬇️
...rc/Microsoft.ML.Featurizers/DateTimeTransformer.cs	87.15% <0.00%> (-1.81%)	⬇️
...crosoft.ML.TimeSeries/RootCauseLocalizationType.cs	49.42% <0.00%> (-1.77%)	⬇️
... and 273 more

[harishsk]