refactor: extract data analysis code into separate analysis module

analysis/pom.xml

@@ -0,0 +1,53 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>net.laprun.sustainability</groupId>
+        <artifactId>power-server-parent</artifactId>
+        <version>0.0.12-SNAPSHOT</version>
+    </parent>
+
+    <artifactId>power-server-analysis</artifactId>
+    <name>power-server : analysis</name>
+    <description>Classes that support analysis of recorded data</description>
+
+    <dependencies>
+        <dependency>
+            <groupId>net.laprun.sustainability</groupId>
+            <artifactId>power-server-measure</artifactId>
+            <version>${project.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.commons</groupId>
+            <artifactId>commons-math3</artifactId>
+            <version>3.6.1</version>
+        </dependency>
+        <dependency>
+            <groupId>org.hdrhistogram</groupId>
+            <artifactId>HdrHistogram</artifactId>
+            <version>2.2.2</version>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <pluginManagement>
+            <plugins>
+                <plugin>
+                    <groupId>net.revelc.code.formatter</groupId>
+                    <artifactId>formatter-maven-plugin</artifactId>
+                    <dependencies>
+                        <dependency>
+                            <groupId>net.laprun.sustainability</groupId>
+                            <artifactId>build-tools</artifactId>
+                            <version>0.0.12-SNAPSHOT</version>
+                        </dependency>
+                    </dependencies>
+                </plugin>
+            </plugins>
+        </pluginManagement>
+    </build>
+
+</project>

analysis/src/main/java/net/laprun/sustainability/power/analysis/Compute.java

@@ -0,0 +1,35 @@
+package net.laprun.sustainability.power.analysis;
+
+import org.apache.commons.math3.util.FastMath;
+
+import net.laprun.sustainability.power.measure.PowerMeasure;
+
+public enum Compute {
+    ;
+
+    public static double standardDeviation(PowerMeasure measure, int componentIndex) {
+        return measure.getMeasuresFor(componentIndex).map(values -> {
+            final var samples = values.length;
+            if (samples <= 1) {
+                return 0.0;
+            }
+            final double mean = average(measure, componentIndex);
+            double geometricDeviationTotal = 0.0;
+            for (double value : values) {
+                double deviation = value - mean;
+                geometricDeviationTotal += (deviation * deviation);
+            }
+            return FastMath.sqrt(geometricDeviationTotal / (samples - 1));
+        }).orElse(0.0);
+    }
+
+    public static double average(PowerMeasure measure, int componentIndex) {
+        return measure.getMeasuresFor(componentIndex).map(values -> {
+            double sum = 0.0;
+            for (double value : values) {
+                sum += value;
+            }
+            return sum / values.length;
+        }).orElse(0.0);
+    }
+}

measure/src/main/java/net/laprun/sustainability/power/measure/DescriptiveStatisticsAnalyzer.java → analysis/src/main/java/net/laprun/sustainability/power/analysis/DescriptiveStatisticsComponentProcessor.java

@@ -1,12 +1,12 @@
-package net.laprun.sustainability.power.measure;
+package net.laprun.sustainability.power.analysis;
 
 import org.apache.commons.math3.stat.descriptive.DescriptiveStatistics;
 
 @SuppressWarnings("unused")
-public class DescriptiveStatisticsAnalyzer implements Analyzer {
+public class DescriptiveStatisticsComponentProcessor implements ComponentProcessor {
     private final DescriptiveStatistics statistics;
 
-    public DescriptiveStatisticsAnalyzer() {
+    public DescriptiveStatisticsComponentProcessor() {
         statistics = new DescriptiveStatistics();
     }
 

measure/src/main/java/net/laprun/sustainability/power/measure/HdrHistogramAnalyzer.java → analysis/src/main/java/net/laprun/sustainability/power/analysis/HdrHistogramComponentProcessor.java

@@ -1,15 +1,15 @@
-package net.laprun.sustainability.power.measure;
+package net.laprun.sustainability.power.analysis;
 
 import org.HdrHistogram.IntCountsHistogram;
 
 @SuppressWarnings("unused")
-public class HdrHistogramAnalyzer implements Analyzer {
+public class HdrHistogramComponentProcessor implements ComponentProcessor {
     private static final int HIGHEST_TRACKABLE_VALUE = 1_000_000;
     private static final int NUMBER_OF_SIGNIFICANT_VALUE_DIGITS = 4;
     private static final int CONVERSION_FACTOR = 1000;
     private final IntCountsHistogram histogram;
 
-    public HdrHistogramAnalyzer() {
+    public HdrHistogramComponentProcessor() {
         histogram = new IntCountsHistogram(HIGHEST_TRACKABLE_VALUE, NUMBER_OF_SIGNIFICANT_VALUE_DIGITS);
     }
 

analysis/src/main/java/net/laprun/sustainability/power/analysis/MeanComponentProcessor.java

@@ -0,0 +1,13 @@
+package net.laprun.sustainability.power.analysis;
+
+public class MeanComponentProcessor implements ComponentProcessor {
+    private double mean;
+    private int count;
+
+    @Override
+    public void recordComponentValue(double value, long timestamp) {
+        final var previousSize = count;
+        count++;
+        mean = mean == 0 ? value : (previousSize * mean + value) / count;
+    }
+}

analysis/src/test/java/ComputeTest.java

@@ -0,0 +1,110 @@
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.util.Map;
+import java.util.Random;
+import java.util.random.RandomGenerator;
+
+import org.junit.jupiter.api.Test;
+
+import net.laprun.sustainability.power.SensorMetadata;
+import net.laprun.sustainability.power.analysis.Compute;
+import net.laprun.sustainability.power.measure.OngoingPowerMeasure;
+
+public class ComputeTest {
+    private final static SensorMetadata metadata = new SensorMetadata(Map.of(), null, new int[0]) {
+
+        @Override
+        public int componentCardinality() {
+            return 3;
+        }
+    };
+
+    @Test
+    void standardDeviationShouldWork() {
+        final var random = Random.from(RandomGenerator.getDefault());
+        final var m1c1 = random.nextDouble();
+        final var m1c2 = random.nextDouble();
+        final var m1c3 = 0.0;
+        final var m2c1 = random.nextDouble();
+        final var m2c2 = random.nextDouble();
+        final var m2c3 = 0.0;
+        final var m3c1 = random.nextDouble();
+        final var m3c2 = random.nextDouble();
+        final var m3c3 = 0.0;
+
+        final var measure = new OngoingPowerMeasure(metadata);
+
+        final var components = new double[metadata.componentCardinality()];
+        components[0] = m1c1;
+        components[1] = m1c2;
+        components[2] = m1c3;
+        measure.recordMeasure(components);
+
+        components[0] = m2c1;
+        components[1] = m2c2;
+        components[2] = m2c3;
+        measure.recordMeasure(components);
+
+        components[0] = m3c1;
+        components[1] = m3c2;
+        components[2] = m3c3;
+        measure.recordMeasure(components);
+
+        final var c1Avg = Compute.average(measure, 0);
+        final var c2Avg = Compute.average(measure, 1);
+        final var stdVarForC1 = Math
+                .sqrt((Math.pow(m1c1 - c1Avg, 2) + Math.pow(m2c1 - c1Avg, 2) + Math.pow(m3c1 - c1Avg, 2)) / (3 - 1));
+        final var stdVarForC2 = Math
+                .sqrt((Math.pow(m1c2 - c2Avg, 2) + Math.pow(m2c2 - c2Avg, 2) + Math.pow(m3c2 - c2Avg, 2)) / (3 - 1));
+
+        assertEquals(stdVarForC1, Compute.standardDeviation(measure, 0), 0.0001,
+                "Standard Deviation did not match the expected value");
+        assertEquals(stdVarForC2, Compute.standardDeviation(measure, 1), 0.0001,
+                "Standard Deviation did not match the expected value");
+        assertEquals(0, Compute.standardDeviation(measure, 2), 0.0001,
+                "Standard Deviation did not match the expected value");
+    }
+
+    @Test
+    void averageShouldWork() {
+        final var random = Random.from(RandomGenerator.getDefault());
+        final var m1c1 = random.nextDouble();
+        final var m1c2 = random.nextDouble();
+        final var m1c3 = 0.0;
+        final var m2c1 = random.nextDouble();
+        final var m2c2 = random.nextDouble();
+        final var m2c3 = 0.0;
+        final var m3c1 = random.nextDouble();
+        final var m3c2 = random.nextDouble();
+        final var m3c3 = 0.0;
+
+        final var measure = new OngoingPowerMeasure(metadata);
+
+        final var components = new double[metadata.componentCardinality()];
+        components[0] = m1c1;
+        components[1] = m1c2;
+        components[2] = m1c3;
+        measure.recordMeasure(components);
+
+        components[0] = m2c1;
+        components[1] = m2c2;
+        components[2] = m2c3;
+        measure.recordMeasure(components);
+
+        components[0] = m3c1;
+        components[1] = m3c2;
+        components[2] = m3c3;
+        measure.recordMeasure(components);
+
+        final var c1Avg = Compute.average(measure, 0);
+        final var c2Avg = Compute.average(measure, 1);
+        final var c3Avg = Compute.average(measure, 2);
+
+        assertEquals((m1c1 + m2c1 + m3c1) / 3, c1Avg, 0.0001,
+                "Average did not match the expected value");
+        assertEquals((m1c2 + m2c2 + m3c2) / 3, c2Avg, 0.0001,
+                "Average did not match the expected value");
+        assertEquals(0, c3Avg, 0.0001,
+                "Average did not match the expected value");
+    }
+}

measure/pom.xml

@@ -19,14 +19,10 @@
       <version>${project.version}</version>
     </dependency>
     <dependency>
-      <groupId>org.apache.commons</groupId>
-      <artifactId>commons-math3</artifactId>
-      <version>3.6.1</version>
-    </dependency>
-    <dependency>
-      <groupId>org.hdrhistogram</groupId>
-      <artifactId>HdrHistogram</artifactId>
-      <version>2.2.2</version>
+      <groupId>org.assertj</groupId>
+      <artifactId>assertj-core</artifactId>
+      <version>3.26.3</version>
+      <scope>test</scope>
     </dependency>
   </dependencies>
 

measure/src/main/java/net/laprun/sustainability/power/analysis/Analyzers.java

@@ -0,0 +1,4 @@
+package net.laprun.sustainability.power.analysis;
+
+public interface Analyzers {
+}

measure/src/main/java/net/laprun/sustainability/power/analysis/ComponentProcessor.java

@@ -0,0 +1,6 @@
+package net.laprun.sustainability.power.analysis;
+
+public interface ComponentProcessor {
+    default void recordComponentValue(double value, long timestamp) {
+    }
+}

measure/src/main/java/net/laprun/sustainability/power/measure/Compute.java

@@ -0,0 +1,24 @@
+package net.laprun.sustainability.power.measure;
+
+public enum Compute {
+    ;
+
+    public static double sumOfComponents(double[] recorded) {
+        var componentSum = 0.0;
+        for (double value : recorded) {
+            componentSum += value;
+        }
+        return componentSum;
+    }
+
+    public static double sumOfSelectedComponents(double[] recorded, int... indices) {
+        if (indices == null || indices.length == 0) {
+            return sumOfComponents(recorded);
+        }
+        var componentSum = 0.0;
+        for (int index : indices) {
+            componentSum += recorded[index];
+        }
+        return componentSum;
+    }
+}