Samuele Locatelli
329 lines
11 KiB
C#
329 lines
11 KiB
C#
/* ========================================================================
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* Copyright (c) 2005-2020 The OPC Foundation, Inc. All rights reserved.
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*
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* OPC Foundation MIT License 1.00
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following
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* conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*
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* The complete license agreement can be found here:
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* http://opcfoundation.org/License/MIT/1.00/
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* ======================================================================*/
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using System;
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using System.Collections.Generic;
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using System.Text;
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namespace Opc.Ua.Server
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{
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/// <summary>
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/// Calculates the value of an aggregate.
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/// </summary>
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public class StdDevAggregateCalculator : AggregateCalculator
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{
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#region Constructors
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/// <summary>
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/// Initializes the aggregate calculator.
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/// </summary>
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/// <param name="aggregateId">The aggregate function to apply.</param>
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/// <param name="startTime">The start time.</param>
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/// <param name="endTime">The end time.</param>
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/// <param name="processingInterval">The processing interval.</param>
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/// <param name="stepped">Whether to use stepped interpolation.</param>
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/// <param name="configuration">The aggregate configuration.</param>
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public StdDevAggregateCalculator(
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NodeId aggregateId,
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DateTime startTime,
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DateTime endTime,
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double processingInterval,
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bool stepped,
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AggregateConfiguration configuration)
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:
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base(aggregateId, startTime, endTime, processingInterval, stepped, configuration)
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{
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SetPartialBit = true;
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}
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#endregion
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#region Overridden Methods
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/// <summary>
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/// Computes the value for the timeslice.
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/// </summary>
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protected override DataValue ComputeValue(TimeSlice slice)
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{
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uint? id = AggregateId.Identifier as uint?;
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if (id != null)
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{
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switch (id.Value)
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{
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case Objects.AggregateFunction_StandardDeviationPopulation:
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{
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return ComputeStdDev(slice, false, 1);
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}
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case Objects.AggregateFunction_StandardDeviationSample:
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{
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return ComputeStdDev(slice, false, 2);
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}
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case Objects.AggregateFunction_VariancePopulation:
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{
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return ComputeStdDev(slice, true, 1);
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}
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case Objects.AggregateFunction_VarianceSample:
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{
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return ComputeStdDev(slice, true, 2);
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}
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}
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}
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return base.ComputeValue(slice);
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}
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#endregion
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#region Protected Methods
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/// <summary>
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/// Calculates the RegSlope, RegConst and RegStdDev aggregates for the timeslice.
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/// </summary>
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protected DataValue ComputeRegression(TimeSlice slice, int valueType)
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{
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// get the values in the slice.
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List<DataValue> values = GetValuesWithSimpleBounds(slice);
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// check for empty slice.
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if (values == null || values.Count == 0)
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{
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return GetNoDataValue(slice);
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}
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// get the regions.
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List<SubRegion> regions = GetRegionsInValueSet(values, false, true);
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List<double> xData = new List<double>();
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List<double> yData = new List<double>();
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double duration = 0;
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bool nonGoodDataExists = false;
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for (int ii = 0; ii < regions.Count; ii++)
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{
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if (StatusCode.IsGood(regions[ii].StatusCode))
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{
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xData.Add(regions[ii].StartValue);
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yData.Add(duration);
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}
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else
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{
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nonGoodDataExists = true;
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}
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// normalize to seconds.
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duration += regions[ii].Duration/1000.0;
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}
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// check if no good data.
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if (xData.Count == 0)
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{
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return GetNoDataValue(slice);
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}
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// compute the regression parameters.
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double regSlope = 0;
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double regConst = 0;
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double regStdDev = 0;
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if (xData.Count > 1)
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{
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double xAvg = 0;
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double yAvg = 0;
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double xxAgv = 0;
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double xyAvg = 0;
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for (int ii = 0; ii < xData.Count; ii++)
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{
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xAvg += xData[ii];
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yAvg += yData[ii];
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xxAgv += xData[ii] * xData[ii];
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xyAvg += xData[ii] * yData[ii];
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}
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xAvg /= xData.Count;
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yAvg /= xData.Count;
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xxAgv /= xData.Count;
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xyAvg /= xData.Count;
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regSlope = (xyAvg - xAvg * yAvg) / (xxAgv - xAvg * xAvg);
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regConst = yAvg - regSlope * xAvg;
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List<double> errors = new List<double>();
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double eAvg = 0;
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for (int ii = 0; ii < xData.Count; ii++)
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{
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double error = yData[ii] - regConst - regSlope * xData[ii];
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errors.Add(error);
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eAvg += error;
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}
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eAvg /= errors.Count;
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double variance = 0;
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for (int ii = 0; ii < errors.Count; ii++)
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{
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double error = errors[ii] - eAvg;
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variance += error * error;
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}
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variance /= errors.Count;
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regStdDev = Math.Sqrt(variance);
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}
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// select the result.
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double result = 0;
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switch (valueType)
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{
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case 1: { result = regSlope; break; }
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case 2: { result = regConst; break; }
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case 3: { result = regStdDev; break; }
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}
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// set the timestamp and status.
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DataValue value = new DataValue();
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value.WrappedValue = new Variant(result, TypeInfo.Scalars.Double);
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value.SourceTimestamp = GetTimestamp(slice);
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value.ServerTimestamp = GetTimestamp(slice);
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if (nonGoodDataExists)
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{
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value.StatusCode = StatusCodes.UncertainDataSubNormal;
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}
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value.StatusCode = value.StatusCode.SetAggregateBits(AggregateBits.Calculated);
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// return result.
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return value;
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}
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/// <summary>
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/// Calculates the StdDev, Variance, StdDev2 and Variance2 aggregates for the timeslice.
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/// </summary>
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protected DataValue ComputeStdDev(TimeSlice slice, bool includeBounds, int valueType)
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{
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// get the values in the slice.
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List<DataValue> values = null;
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if (includeBounds)
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{
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values = GetValuesWithSimpleBounds(slice);
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}
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else
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{
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values = GetValues(slice);
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}
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// check for empty slice.
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if (values == null || values.Count == 0)
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{
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return GetNoDataValue(slice);
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}
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// get the regions.
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List<SubRegion> regions = GetRegionsInValueSet(values, false, true);
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List<double> xData = new List<double>();
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double average = 0;
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bool nonGoodDataExists = false;
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for (int ii = 0; ii < regions.Count; ii++)
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{
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if (StatusCode.IsGood(regions[ii].StatusCode))
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{
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xData.Add(regions[ii].StartValue);
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average += regions[ii].StartValue;
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}
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else
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{
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nonGoodDataExists = true;
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}
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}
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// check if no good data.
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if (xData.Count == 0)
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{
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return GetNoDataValue(slice);
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}
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average /= xData.Count;
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// calculate variance.
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double variance = 0;
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for (int ii = 0; ii < xData.Count; ii++)
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{
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double error = xData[ii] - average;
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variance += error*error;
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}
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// use the sample variance if bounds are included.
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if (includeBounds)
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{
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variance /= (xData.Count + 1);
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}
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// use the population variance if bounds are not included.
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else
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{
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variance /= xData.Count;
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}
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// select the result.
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double result = 0;
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switch (valueType)
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{
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case 1: { result = Math.Sqrt(variance); break; }
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case 2: { result = variance; break; }
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}
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// set the timestamp and status.
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DataValue value = new DataValue();
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value.WrappedValue = new Variant(result, TypeInfo.Scalars.Double);
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value.SourceTimestamp = GetTimestamp(slice);
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value.ServerTimestamp = GetTimestamp(slice);
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if (nonGoodDataExists)
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{
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value.StatusCode = StatusCodes.UncertainDataSubNormal;
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}
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value.StatusCode = value.StatusCode.SetAggregateBits(AggregateBits.Calculated);
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// return result.
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return value;
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}
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#endregion
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}
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}
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