Merge pull request #1523 from nosqlbench/nosqlbench-1522-moremath

Nosqlbench 1522 moremath

engine-extensions/src/main/java/io/nosqlbench/engine/extensions/computefunctions/ComputeFunctions.java

@@ -40,8 +40,11 @@ public class ComputeFunctions {
 
     /**
      * Compute the recall as the proportion of matching indices divided by the expected indices
-     * @param referenceIndexes long array of indices
+     *
-     * @param sampleIndexes long array of indices
+     * @param referenceIndexes
+     *     long array of indices
+     * @param sampleIndexes
+     *     long array of indices
      * @return a fractional measure of matching vs expected indices
      */
     public static double recall(long[] referenceIndexes, long[] sampleIndexes) {
@@ -50,6 +53,7 @@ public class ComputeFunctions {
         long[] intersection = Intersections.find(referenceIndexes, sampleIndexes);
         return (double) intersection.length / (double) referenceIndexes.length;
     }
+
     public static double recall(long[] referenceIndexes, long[] sampleIndexes, int limit) {
         if (sampleIndexes.length < limit) {
             throw new RuntimeException("indices fewer than limit, invalid precision computation: index count=" + sampleIndexes.length + ", limit=" + limit);
@@ -81,8 +85,11 @@ public class ComputeFunctions {
 
     /**
      * Compute the recall as the proportion of matching indices divided by the expected indices
-     * @param referenceIndexes int array of indices
+     *
-     * @param sampleIndexes int array of indices
+     * @param referenceIndexes
+     *     int array of indices
+     * @param sampleIndexes
+     *     int array of indices
      * @return a fractional measure of matching vs expected indices
      */
     public static double recall(int[] referenceIndexes, int[] sampleIndexes) {
@@ -91,6 +98,7 @@ public class ComputeFunctions {
         int intersection = Intersections.count(referenceIndexes, sampleIndexes, referenceIndexes.length);
         return (double) intersection / (double) referenceIndexes.length;
     }
+
     public static double recall(int[] referenceIndexes, int[] sampleIndexes, int limit) {
         if (sampleIndexes.length < limit) {
             throw new RuntimeException("indices fewer than limit, invalid precision computation: index count=" + sampleIndexes.length + ", limit=" + limit);
@@ -108,6 +116,7 @@ public class ComputeFunctions {
         int intersection = Intersections.count(referenceIndexes, sampleIndexes);
         return (double) intersection / (double) sampleIndexes.length;
     }
+
     public static double precision(int[] referenceIndexes, int[] sampleIndexes, int limit) {
         if (sampleIndexes.length < limit) {
             throw new RuntimeException("indices fewer than limit, invalid precision computation: index count=" + sampleIndexes.length + ", limit=" + limit);
@@ -125,6 +134,7 @@ public class ComputeFunctions {
     public static long[] intersection(long[] a, long[] b) {
         return Intersections.find(a, b);
     }
+
     public static long[] intersection(long[] a, long[] b, int limit) {
         return Intersections.find(a, b, limit);
     }
@@ -146,14 +156,66 @@ public class ComputeFunctions {
     public static int intersectionSize(int[] reference, int[] sample) {
         return Intersections.count(reference, sample);
     }
+
     public static int intersectionSize(int[] reference, int[] sample, int limit) {
         return Intersections.count(reference, sample, limit);
     }
+
     public static int intersectionSize(long[] reference, long[] sample) {
         return Intersections.count(reference, sample);
     }
+
     public static int intersectionSize(long[] reference, long[] sample, int limit) {
         return Intersections.count(reference, sample, limit);
     }
 
+    public static double F1(int[] reference, int[] sample) {
+        return F1(reference, sample, reference.length);
+    }
+
+    public static double F1(int[] reference, int[] sample, int limit) {
+        double recallAtK = recall(reference, sample, limit);
+        double precisionAtK = precision(reference, sample, limit);
+        return 2.0d * ((recallAtK * precisionAtK) / (recallAtK + precisionAtK));
+    }
+
+    public static double F1(long[] reference, long[] sample) {
+        return F1(reference, sample, reference.length);
+    }
+
+    public static double F1(long[] reference, long[] sample, int limit) {
+        double recallAtK = recall(reference, sample, limit);
+        double precisionAtK = precision(reference, sample, limit);
+        return 2.0d * ((recallAtK * precisionAtK) / (recallAtK + precisionAtK));
+    }
+
+    /**
+     * Reciprocal Rank - The multiplicative inverse of the first rank which is relevant.
+     */
+    public static double RR(long[] reference, long[] sample, int limit) {
+        int firstRank = Intersections.firstMatchingIndex(reference, sample, limit);
+        if (firstRank >= 0) {
+            return 1.0d / (firstRank+1);
+        } else {
+            return 0.0;
+        }
+    }
+
+    public static double RR(long[] reference, long[] sample) {
+        return RR(reference, sample, reference.length);
+    }
+
+    public static double RR(int[] reference, int[] sample, int limit) {
+        int firstRank = Intersections.firstMatchingIndex(reference, sample, limit);
+        if (firstRank >= 0) {
+            return 1.0d / (firstRank+1);
+        } else {
+            return 0.0;
+        }
+    }
+
+    public static double RR(int[] reference, int[] sample) {
+        return RR(reference, sample, reference.length);
+    }
+
 }

engine-extensions/src/main/java/io/nosqlbench/engine/extensions/computefunctions/Intersections.java

@@ -20,6 +20,32 @@ import java.util.Arrays;
 
 public class Intersections {
 
+    /**
+     * Return a non-negative index of the first value in the sample array which is present in the reference array,
+     * OR, return a negative number. This returns array index which start at 0, not rank, which is starts at 1.
+     */
+    public static int firstMatchingIndex(long[] reference, long[] sample, int limit) {
+        Arrays.sort(reference);
+        int maxIndex = Math.min(sample.length, limit);
+        int foundAt=-1;
+        for (int index = 0; index < maxIndex; index++) {
+            foundAt = Arrays.binarySearch(reference, sample[index]);
+            if (foundAt>=0) break;
+        }
+        return foundAt;
+    }
+
+    public static int firstMatchingIndex(int[] reference, int[] sample, int limit) {
+        Arrays.sort(reference);
+        int maxIndex = Math.min(sample.length, limit);
+        int foundAt=-1;
+        for (int index = 0; index < maxIndex; index++) {
+            foundAt = Arrays.binarySearch(reference, sample[index]);
+            if (foundAt>=0) break;
+        }
+        return foundAt;
+    }
+
     public static int count(int[] reference, int[] sample) {
         return count(reference,sample,reference.length);
     }

engine-extensions/src/test/java/io/nosqlbench/engine/extensions/computefunctions/ComputeFunctionsTest.java

@@ -78,4 +78,15 @@ class ComputeFunctionsTest {
         }
 
     }
+
+    @Test
+    public void testReciprocalRank() {
+        assertThat(ComputeFunctions.RR(intsBy3_369,highInts56789))
+            .as("relevant results in rank 2 should yield RR=0.5")
+            .isCloseTo(0.5d,offset);
+
+        assertThat(ComputeFunctions.RR(highInts56789,lowInts01234))
+            .as("no relevant results should yield RR=0.0")
+            .isCloseTo(0.0d,offset);
+    }
 }