org.numenta.nupic.algorithms.Anomaly Maven / Gradle / Ivy
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* Numenta Platform for Intelligent Computing (NuPIC)
* Copyright (C) 2014, Numenta, Inc. Unless you have an agreement
* with Numenta, Inc., for a separate license for this software code, the
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details.
*
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package org.numenta.nupic.algorithms;
import gnu.trove.list.TDoubleList;
import gnu.trove.list.array.TDoubleArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.numenta.nupic.util.ArrayUtils;
/**
* This module analyzes and estimates the distribution of averaged anomaly scores
* from a CLA model. Given a new anomaly score `s`, estimates `P(score >= s)`.
*
* The number `P(score >= s)` represents the likelihood of the current state of
* predictability. For example, a likelihood of 0.01 or 1% means we see this much
* predictability about one out of every 100 records. The number is not as unusual
* as it seems. For records that arrive every minute, this means once every hour
* and 40 minutes. A likelihood of 0.0001 or 0.01% means we see it once out of
* 10,000 records, or about once every 7 days.
*
* USAGE
* -----
*
* The {@code Anomaly} base class follows the factory pattern and can construct an
* appropriately configured anomaly calculator by invoking the following:
*
*
* Map params = new HashMap<>();
* params.put(KEY_MODE, Mode.LIKELIHOOD); // May be Mode.PURE or Mode.WEIGHTED
* params.put(KEY_USE_MOVING_AVG, true); // Instructs the Anomaly class to compute moving average
* params.put(KEY_WINDOW_SIZE, 10); // #of inputs over which to compute the moving average
* params.put(KEY_IS_WEIGHTED, true); // Use a weighted moving average or not
*
* // Instantiate the Anomaly computer
* Anomaly anomalyComputer = Anomaly.create(params); // Returns the appropriate Anomaly
* // implementation.
* int[] actual = array of input columns at time t
* int[] predicted = array of predicted columns for t+1
* double anomaly = an.compute(
* actual,
* predicted,
* 0 (inputValue = OPTIONAL, needed for likelihood calcs),
* timestamp);
*
* double anomalyProbability = anomalyComputer.anomalyProbability(
* inputValue, anomaly, timestamp);
*
*
* Raw functions
* -------------
*
* There are two lower level functions, estimateAnomalyLikelihoods and
* updateAnomalyLikelihoods. The details of these are described by the method docs.
*
* For more information please see: {@link AnomalyTest} and {@link AnomalyLikelihoodTest}
*
* @author Numenta
* @author David Ray
* @see AnomalyTest
* @see AnomalyLikelihoodTest
*/
public abstract class Anomaly {
/** Modes to use for factory creation method */
public enum Mode { PURE, LIKELIHOOD, WEIGHTED };
// Instantiation keys
public static final int VALUE_NONE = -1;
public static final String KEY_MODE = "mode".intern();
public static final String KEY_LEARNING_PERIOD = "claLearningPeriod";
public static final String KEY_ESTIMATION_SAMPLES = "estimationSamples";
public static final String KEY_USE_MOVING_AVG = "useMovingAverage";
public static final String KEY_WINDOW_SIZE = "windowSize".intern();
public static final String KEY_IS_WEIGHTED = "isWeighted";
// Configs
public static final String KEY_DIST = "distribution".intern();
public static final String KEY_MVG_AVG = "movingAverage".intern();
public static final String KEY_HIST_LIKE = "historicalLikelihoods".intern();
public static final String KEY_HIST_VALUES = "historicalValues".intern();
public static final String KEY_TOTAL = "total".intern();
// Computational argument keys
public final static String KEY_MEAN = "mean".intern();
public final static String KEY_STDEV = "stdev".intern();
public final static String KEY_VARIANCE = "variance".intern();
protected MovingAverage movingAverage;
protected boolean useMovingAverage;
/**
* Constructs a new {@code Anomaly}
*/
public Anomaly() {
this(false, -1);
}
/**
* Constructs a new {@code Anomaly}
*
* @param useMovingAverage indicates whether to apply and store a moving average
* @param windowSize size of window to average over
*/
protected Anomaly(boolean useMovingAverage, int windowSize) {
this.useMovingAverage = useMovingAverage;
if(this.useMovingAverage) {
if(windowSize < 1) {
throw new IllegalArgumentException(
"Window size must be > 0, when using moving average.");
}
movingAverage = new MovingAverage(null, windowSize);
}
}
/**
* Convenience method to create a simplistic Anomaly computer in
* {@link Mode#PURE}
*
* @return
*/
public static Anomaly create() {
Map params = new HashMap<>();
params.put(KEY_MODE, Mode.PURE);
return create(params);
}
/**
* Returns an {@code Anomaly} configured to execute the type
* of calculation specified by the {@link Mode}, and whether or
* not to apply a moving average.
*
* Must have one of "MODE" = {@link Mode#LIKELIHOOD}, {@link Mode#PURE}, {@link Mode#WEIGHTED}
*
* @param p Map
* @return
*/
public static Anomaly create(Map params) {
boolean useMovingAvg = (boolean)params.getOrDefault(KEY_USE_MOVING_AVG, false);
int windowSize = (int)params.getOrDefault(KEY_WINDOW_SIZE, -1);
if(useMovingAvg && windowSize < 1) {
throw new IllegalArgumentException("windowSize must be > 0, when using moving average.");
}
Mode mode = (Mode)params.get(KEY_MODE);
if(mode == null) {
throw new IllegalArgumentException("MODE cannot be null.");
}
switch(mode) {
case PURE: return new Anomaly(useMovingAvg, windowSize) {
@Override
public double compute(int[] activeColumns, int[] predictedColumns, double inputValue, long timestamp) {
double retVal = computeRawAnomalyScore(activeColumns, predictedColumns);
if(this.useMovingAverage) {
retVal = movingAverage.next(retVal);
}
return retVal;
}};
case LIKELIHOOD:
case WEIGHTED: {
boolean isWeighted = (boolean)params.getOrDefault(KEY_IS_WEIGHTED, false);
int claLearningPeriod = (int)params.getOrDefault(KEY_LEARNING_PERIOD, VALUE_NONE);
int estimationSamples = (int)params.getOrDefault(KEY_ESTIMATION_SAMPLES, VALUE_NONE);
return new AnomalyLikelihood(useMovingAvg, windowSize, isWeighted, claLearningPeriod, estimationSamples);
}
default: return null;
}
}
/**
* The raw anomaly score is the fraction of active columns not predicted.
*
* @param activeColumns an array of active column indices
* @param prevPredictedColumns array of column indices predicted in the
* previous step
* @return anomaly score 0..1
*/
public static double computeRawAnomalyScore(int[] activeColumns, int[] prevPredictedColumns) {
double score = 0;
int nActiveColumns = activeColumns.length;
if(nActiveColumns > 0) {
// Test whether each element of a 1-D array is also present in a second
// array. Sum to get the total # of columns that are active and were
// predicted.
score = ArrayUtils.in1d(activeColumns, prevPredictedColumns).length;
// Get the percent of active columns that were NOT predicted, that is
// our anomaly score.
score = (nActiveColumns - score) / (double)nActiveColumns;
}else if(prevPredictedColumns.length > 0) {
score = 1.0d;
}
return score;
}
/**
* Compute the anomaly score as the percent of active columns not predicted.
*
* @param activeColumns array of active column indices
* @param predictedColumns array of columns indices predicted in this step
* (used for anomaly in step T+1)
* @param inputValue (optional) value of current input to encoders
* (eg "cat" for category encoder)
* (used in anomaly-likelihood)
* @param timestamp timestamp: (optional) date timestamp when the sample occurred
* (used in anomaly-likelihood)
* @return
*/
public abstract double compute(int[] activeColumns, int[] predictedColumns, double inputValue, long timestamp);
//////////////////////////////////////////////////////////////////////////////////////
// Inner Class Definitions //
//////////////////////////////////////////////////////////////////////////////////////
/**
* Container to hold interim {@link AnomalyLikelihood} calculations.
*
* @author David Ray
* @see AnomalyLikelihood
* @see MovingAverage
*/
public class AveragedAnomalyRecordList {
List averagedRecords;
TDoubleList historicalValues;
double total;
/**
* Constructs a new {@code AveragedAnomalyRecordList}
*
* @param averagedRecords List of samples which are { timestamp, average, value } at a data point
* @param historicalValues List of values of a given window size (moving average grouping)
* @param total Sum of all values in the series
*/
public AveragedAnomalyRecordList(List averagedRecords, TDoubleList historicalValues, double total) {
this.averagedRecords = averagedRecords;
this.historicalValues = historicalValues;
this.total = total;
}
/**
* Returns a list of the averages in the contained averaged record list.
* @return
*/
public TDoubleList getMetrics() {
TDoubleList retVal = new TDoubleArrayList();
for(Sample s : averagedRecords) {
retVal.add(s.score);
}
return retVal;
}
/**
* Returns a list of the sample values in the contained averaged record list.
* @return
*/
public TDoubleList getSamples() {
TDoubleList retVal = new TDoubleArrayList();
for(Sample s : averagedRecords) {
retVal.add(s.value);
}
return retVal;
}
/**
* Returns the size of the count of averaged records (i.e. {@link Sample}s)
* @return
*/
public int size() {
return averagedRecords.size(); //let fail if null
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((averagedRecords == null) ? 0 : averagedRecords.hashCode());
result = prime * result + ((historicalValues == null) ? 0 : historicalValues.hashCode());
long temp;
temp = Double.doubleToLongBits(total);
result = prime * result + (int)(temp ^ (temp >>> 32));
return result;
}
@Override
public boolean equals(Object obj) {
if(this == obj)
return true;
if(obj == null)
return false;
if(getClass() != obj.getClass())
return false;
AveragedAnomalyRecordList other = (AveragedAnomalyRecordList)obj;
if(averagedRecords == null) {
if(other.averagedRecords != null)
return false;
} else if(!averagedRecords.equals(other.averagedRecords))
return false;
if(historicalValues == null) {
if(other.historicalValues != null)
return false;
} else if(!historicalValues.equals(other.historicalValues))
return false;
if(Double.doubleToLongBits(total) != Double.doubleToLongBits(other.total))
return false;
return true;
}
}
}
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