benchmark preparations

app/src/jmh/java/de/uni_marburg/powersort/benchmark/BenchmarkJmh.java

@@ -1,11 +1,10 @@
 package de.uni_marburg.powersort.benchmark;
 
 import de.uni_marburg.powersort.TimSort;
-import de.uni_marburg.powersort.data.Data1;
+import de.uni_marburg.powersort.data.RandomIntegers;
 import org.openjdk.jmh.annotations.*;
 import org.openjdk.jmh.infra.Blackhole;
 
-import java.util.Arrays;
 import java.util.concurrent.TimeUnit;
 
 // TODO: The parameters are way too low. Use for debugging only!
@@ -15,9 +14,11 @@ import java.util.concurrent.TimeUnit;
 public class BenchmarkJmh {
     @State(Scope.Benchmark)
     public static class State1 {
-        Data1 d = new Data1();
+        RandomIntegers d = new RandomIntegers();
         Integer[] a;
 
+        // TODO: This is inaccurate.
+        // How to create and use separate arrays for each warmup x iteration x sortAlgorithm ?
         @Setup(Level.Invocation)
         public void setup() {
             a = d.get();

app/src/main/java/de/uni_marburg/powersort/benchmark/IntegerArray.java

@@ -15,4 +15,21 @@ public class IntegerArray {
         }
         return list;
     }
+
+    /**
+     * @return [start, start-1, ..., end+1, end]
+     */
+    public static Integer[] descending(final int start, final int end) {
+        assert start > end;
+
+        Integer[] list = new Integer[start - end + 1];
+        for (int i = 0; i < list.length; i++) {
+            int value = start - i;
+            list[i] = value;
+        }
+
+        assert list[0] == start;
+        assert list[list.length - 1] == end;
+        return list;
+    }
 }

app/src/main/java/de/uni_marburg/powersort/benchmark/Main.java

@@ -1,7 +1,8 @@
 package de.uni_marburg.powersort.benchmark;
 
 import de.uni_marburg.powersort.TimSort;
-import de.uni_marburg.powersort.data.Data1;
+import de.uni_marburg.powersort.data.DescendingIntegers;
+import de.uni_marburg.powersort.data.RandomIntegers;
 import de.uni_marburg.powersort.data.ObjectSupplier;
 
 import java.util.Arrays;
@@ -56,12 +57,19 @@ public class Main {
         };
     }
 
+    /**
+     * The returned ObjectSupplier objects are wrapped by Supplier objects.
+     * This way they are lazily created on their first access.
+     * This saves memory if we work with large lists.
+     */
     static List<Supplier<ObjectSupplier>> getSortInputSuppliers() {
         return Arrays.asList(
                 // Three different random lists.
-                Data1::new,
-                Data1::new,
-                Data1::new
+                RandomIntegers::new,
+                RandomIntegers::new,
+                RandomIntegers::new,
+                // One descending list.
+                DescendingIntegers::new
         );
     }
 }

app/src/main/java/de/uni_marburg/powersort/data/Data1.java

@@ -1,20 +0,0 @@
-package de.uni_marburg.powersort.data;
-
-import de.uni_marburg.powersort.benchmark.IntegerArray;
-
-import java.util.Arrays;
-
-public class Data1 implements IntegerSupplier {
-    private static final int SIZE = 500_000;
-    private final Integer[] readOnly = IntegerArray.random(SIZE);
-
-    @Override
-    public String title() {
-        return "Array of random Integers of size " + SIZE;
-    }
-
-    @Override
-    public Integer[] get() {
-        return Arrays.copyOf(readOnly, readOnly.length);
-    }
-}

app/src/main/java/de/uni_marburg/powersort/data/DescendingIntegers.java

@@ -0,0 +1,16 @@
+package de.uni_marburg.powersort.data;
+
+import de.uni_marburg.powersort.benchmark.IntegerArray;
+
+public class DescendingIntegers extends IntegerSupplier {
+    private static final int SIZE = 50_000_000;
+
+    public DescendingIntegers() {
+        super(IntegerArray.descending(SIZE, 0));
+    }
+
+    @Override
+    public String title() {
+        return "Array of " + SIZE + " descending Integer objects.";
+    }
+}

app/src/main/java/de/uni_marburg/powersort/data/IntegerSupplier.java

@@ -1,8 +1,12 @@
 package de.uni_marburg.powersort.data;
 
-import java.util.function.Supplier;
+public abstract class IntegerSupplier extends ObjectSupplier {
+    IntegerSupplier(Object[] readOnly) {
+        super(readOnly);
+    }
 
-public interface IntegerSupplier extends ObjectSupplier {
-    String title();
-    Integer[] get();
+    @Override
+    public Integer[] get() {
+        return (Integer[]) super.get();
+    }
 }

app/src/main/java/de/uni_marburg/powersort/data/ObjectSupplier.java

@@ -1,8 +1,23 @@
 package de.uni_marburg.powersort.data;
 
-import java.util.function.Supplier;
+import java.util.Arrays;
 
-public interface ObjectSupplier extends Supplier<Object[]> {
-    String title();
-    Object[] get();
+public abstract class  ObjectSupplier {
+    final Object[] readOnly;
+
+    ObjectSupplier(Object[] readOnly) {
+        this.readOnly = readOnly;
+    }
+
+    /**
+     * Descriptive title for the array of objects represented by this object.
+     */
+    public abstract String title();
+
+    /**
+     * @return A fresh copy of the array of objects represented by this object.
+     */
+    public Object[] get(){
+        return Arrays.copyOf(readOnly, readOnly.length);
+    }
 }

app/src/main/java/de/uni_marburg/powersort/data/RandomIntegers.java

@@ -0,0 +1,16 @@
+package de.uni_marburg.powersort.data;
+
+import de.uni_marburg.powersort.benchmark.IntegerArray;
+
+public class RandomIntegers extends IntegerSupplier {
+    private static final int SIZE = 50_000_000;
+
+    public RandomIntegers() {
+        super(IntegerArray.random(SIZE));
+    }
+
+    @Override
+    public String title() {
+        return "Array of " + SIZE + " random Integer objects.";
+    }
+}