TimeSeriesCatalog.DetectAnomalyBySrCnn Method

Definition

Namespace:

Microsoft.ML

Assembly:

Microsoft.ML.TimeSeries.dll

Package:

Microsoft.ML.TimeSeries v3.0.1

Create SrCnnAnomalyEstimator, which detects timeseries anomalies using SRCNN algorithm.

public static Microsoft.ML.Transforms.TimeSeries.SrCnnAnomalyEstimator DetectAnomalyBySrCnn (this Microsoft.ML.TransformsCatalog catalog, string outputColumnName, string inputColumnName, int windowSize = 64, int backAddWindowSize = 5, int lookaheadWindowSize = 5, int averagingWindowSize = 3, int judgementWindowSize = 21, double threshold = 0.3);

static member DetectAnomalyBySrCnn : Microsoft.ML.TransformsCatalog * string * string * int * int * int * int * int * double -> Microsoft.ML.Transforms.TimeSeries.SrCnnAnomalyEstimator

<Extension()>
Public Function DetectAnomalyBySrCnn (catalog As TransformsCatalog, outputColumnName As String, inputColumnName As String, Optional windowSize As Integer = 64, Optional backAddWindowSize As Integer = 5, Optional lookaheadWindowSize As Integer = 5, Optional averagingWindowSize As Integer = 3, Optional judgementWindowSize As Integer = 21, Optional threshold As Double = 0.3) As SrCnnAnomalyEstimator

Parameters

catalog

TransformsCatalog

The transform's catalog.

outputColumnName

String

Name of the column resulting from the transformation of inputColumnName. The column data is a vector of Double. The vector contains 3 elements: alert (1 means anomaly while 0 means normal), raw score, and magnitude of spectual residual.

inputColumnName

String

Name of column to transform. The column data must be Single.

windowSize

Int32

The size of the sliding window for computing spectral residual.

backAddWindowSize

Int32

The number of points to add back of training window. No more than windowSize, usually keep default value.

lookaheadWindowSize

Int32

The number of pervious points used in prediction. No more than windowSize, usually keep default value.

averagingWindowSize

Int32

The size of sliding window to generate a saliency map for the series. No more than windowSize, usually keep default value.

judgementWindowSize

Int32

The size of sliding window to calculate the anomaly score for each data point. No more than windowSize.

threshold

Double

The threshold to determine anomaly, score larger than the threshold is considered as anomaly. Should be in (0,1)

Returns

SrCnnAnomalyEstimator

Examples

using System;
using System.Collections.Generic;
using System.IO;
using Microsoft.ML;
using Microsoft.ML.Data;
using Microsoft.ML.Transforms.TimeSeries;

namespace Samples.Dynamic
{
    public static class DetectAnomalyBySrCnn
    {
        // This example creates a time series (list of Data with the i-th element
        // corresponding to the i-th time slot). The estimator is applied then to
        // identify spiking points in the series.
        public static void Example()
        {
            // Create a new ML context, for ML.NET operations. It can be used for
            // exception tracking and logging, as well as the source of randomness.
            var ml = new MLContext();

            // Generate sample series data with an anomaly
            var data = new List<TimeSeriesData>();
            for (int index = 0; index < 20; index++)
            {
                data.Add(new TimeSeriesData(5));
            }
            data.Add(new TimeSeriesData(10));
            for (int index = 0; index < 5; index++)
            {
                data.Add(new TimeSeriesData(5));
            }

            // Convert data to IDataView.
            var dataView = ml.Data.LoadFromEnumerable(data);

            // Setup the estimator arguments
            string outputColumnName = nameof(SrCnnAnomalyDetection.Prediction);
            string inputColumnName = nameof(TimeSeriesData.Value);

            // The transformed model.
            ITransformer model = ml.Transforms.DetectAnomalyBySrCnn(
                outputColumnName, inputColumnName, 16, 5, 5, 3, 8, 0.35).Fit(
                dataView);

            // Create a time series prediction engine from the model.
            var engine = model.CreateTimeSeriesEngine<TimeSeriesData,
                SrCnnAnomalyDetection>(ml);

            Console.WriteLine($"{outputColumnName} column obtained post-" +
                $"transformation.");

            Console.WriteLine("Data\tAlert\tScore\tMag");

            // Prediction column obtained post-transformation.
            // Data	Alert	Score	Mag

            // Create non-anomalous data and check for anomaly.
            for (int index = 0; index < 20; index++)
            {
                // Anomaly detection.
                PrintPrediction(5, engine.Predict(new TimeSeriesData(5)));
            }

            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.00    0.00
            //5   0   0.03    0.18
            //5   0   0.03    0.18
            //5   0   0.03    0.18
            //5   0   0.03    0.18
            //5   0   0.03    0.18

            // Anomaly.
            PrintPrediction(10, engine.Predict(new TimeSeriesData(10)));

            //10	1	0.47	0.93    <-- alert is on, predicted anomaly

            // Checkpoint the model.
            var modelPath = "temp.zip";
            engine.CheckPoint(ml, modelPath);

            // Load the model.
            using (var file = File.OpenRead(modelPath))
                model = ml.Model.Load(file, out DataViewSchema schema);

            for (int index = 0; index < 5; index++)
            {
                // Anomaly detection.
                PrintPrediction(5, engine.Predict(new TimeSeriesData(5)));
            }

            //5   0   0.31    0.50
            //5   0   0.05    0.30
            //5   0   0.01    0.23
            //5   0   0.00    0.21
            //5   0   0.01    0.25
        }

        private static void PrintPrediction(float value, SrCnnAnomalyDetection
            prediction) =>
            Console.WriteLine("{0}\t{1}\t{2:0.00}\t{3:0.00}", value, prediction
            .Prediction[0], prediction.Prediction[1], prediction.Prediction[2]);

        private class TimeSeriesData
        {
            public float Value;

            public TimeSeriesData(float value)
            {
                Value = value;
            }
        }

        private class SrCnnAnomalyDetection
        {
            [VectorType(3)]
            public double[] Prediction { get; set; }
        }
    }
}