Fixed merge order of FinnSort and added some testing methods

app/src/main/java/de/uni_marburg/powersort/FinnSort/FasterFinnSort.java

@@ -26,6 +26,7 @@ package de.uni_marburg.powersort.FinnSort;
  */
 
 
+import java.util.Arrays;
 import java.util.Comparator;
 
 import static java.lang.Math.pow;
@@ -68,13 +69,13 @@ public class FasterFinnSort<T> {
      * This is the minimum sized sequence that will be merged.  Shorter
      * sequences will be lengthened by calling binarySort.  If the entire
      * array is less than this length, no merges will be performed.
-     *
+     * <p>
      * This constant should be a power of two.  It was 64 in Tim Peter's C
      * implementation, but 32 was empirically determined to work better in
      * this implementation.  In the unlikely event that you set this constant
      * to be a number that's not a power of two, you'll need to change the
      * {@link #minRunLength} computation.
-     *
+     * <p>
      * If you decrease this constant, you must change the stackLen
      * computation in the TimSort constructor, or you risk an
      * ArrayOutOfBounds exception.  See listsort.txt for a discussion
@@ -87,6 +88,7 @@ public class FasterFinnSort<T> {
      * The array being sorted.
      */
     private final T[] a;
+    private final int rangeSize;
 
     /**
      * The comparator for this sort.
@@ -128,9 +130,9 @@ public class FasterFinnSort<T> {
      * A stack of pending runs yet to be merged.  Run i starts at
      * address base[i] and extends for len[i] elements.  It's always
      * true (so long as the indices are in bounds) that:
-     *
+     * <p>
      * runBase[i] + runLen[i] == runBase[i + 1]
-     *
+     * <p>
      * so we could cut the storage for this, but it's a minor amount,
      * and keeping all the info explicit simplifies the code.
      */
@@ -148,23 +150,22 @@ public class FasterFinnSort<T> {
      * @param workBase origin of usable space in work array
      * @param workLen  usable size of work array
      */
-    private FasterFinnSort(T[] a, Comparator<? super T> c, T[] work, int workBase, int workLen) {
+    private FasterFinnSort(T[] a, Comparator<? super T> c, T[] work, int workBase, int workLen, int rangeSize) {
         this.a = a;
         this.c = c;
-
+        this.rangeSize = rangeSize;
         // Allocate temp storage (which may be increased later if necessary)
         int len = a.length;
         int tlen = (len < 2 * INITIAL_TMP_STORAGE_LENGTH) ?
                 len >>> 1 : INITIAL_TMP_STORAGE_LENGTH;
         if (work == null || workLen < tlen || workBase + tlen > work.length) {
             @SuppressWarnings({"unchecked", "UnnecessaryLocalVariable"})
-            T[] newArray = (T[])java.lang.reflect.Array.newInstance
+            T[] newArray = (T[]) java.lang.reflect.Array.newInstance
                     (a.getClass().getComponentType(), tlen);
             tmp = newArray;
             tmpBase = 0;
             tmpLen = tlen;
-        }
+        } else {
-        else {
             tmp = work;
             tmpBase = workBase;
             tmpLen = workLen;
@@ -216,12 +217,12 @@ public class FasterFinnSort<T> {
     public static <T> void sort(T[] a, int lo, int hi, Comparator<? super T> c,
                                 T[] work, int workBase, int workLen) {
         assert c != null && a != null && lo >= 0 && lo <= hi && hi <= a.length;
-
         int nRemaining = hi - lo;
         if (nRemaining < 2)
             return;  // Arrays of size 0 and 1 are always sorted
 
         // If array is small, do a "mini-TimSort" with no merges
+
         if (nRemaining < MIN_MERGE) {
             int initRunLen = countRunAndMakeAscending(a, lo, hi, c);
             binarySort(a, lo, hi, lo + initRunLen, c);
@@ -233,7 +234,7 @@ public class FasterFinnSort<T> {
          * extending short natural runs to minRun elements, and merging runs
          * to maintain stack invariant.
          */
-        FasterFinnSort<T> ts = new FasterFinnSort<>(a, c, work, workBase, workLen);
+        FasterFinnSort<T> fs = new FasterFinnSort<>(a, c, work, workBase, workLen, hi - lo);
         int minRun = minRunLength(nRemaining);
         do {
             // Identify next run
@@ -247,8 +248,8 @@ public class FasterFinnSort<T> {
             }
 
             // Push run onto pending-run stack, and maybe merge
-            ts.pushRun(lo, runLen, hi - lo);
+            fs.pushRun(lo, runLen);
-            ts.mergeCollapse();
+            fs.mergeCollapse();
 
             // Advance to find next run
             lo += runLen;
@@ -257,8 +258,8 @@ public class FasterFinnSort<T> {
 
         // Merge all remaining runs to complete sort
         assert lo == hi;
-        ts.mergeForceCollapse();
+        fs.mergeForceCollapse();
-        assert ts.stackSize == 1;
+        assert fs.stackSize == 1;
     }
 
     /**
@@ -266,7 +267,7 @@ public class FasterFinnSort<T> {
      * insertion sort.  This is the best method for sorting small numbers
      * of elements.  It requires O(n log n) compares, but O(n^2) data
      * movement (worst case).
-     *
+     * <p>
      * If the initial part of the specified range is already sorted,
      * this method can take advantage of it: the method assumes that the
      * elements from index {@code lo}, inclusive, to {@code start},
@@ -285,7 +286,7 @@ public class FasterFinnSort<T> {
         assert lo <= start && start <= hi;
         if (start == lo)
             start++;
-        for ( ; start < hi; start++) {
+        for (; start < hi; start++) {
             T pivot = a[start];
 
             // Set left (and right) to the index where a[start] (pivot) belongs
@@ -329,15 +330,15 @@ public class FasterFinnSort<T> {
      * Returns the length of the run beginning at the specified position in
      * the specified array and reverses the run if it is descending (ensuring
      * that the run will always be ascending when the method returns).
-     *
+     * <p>
      * A run is the longest ascending sequence with:
-     *
+     * <p>
      * a[lo] <= a[lo + 1] <= a[lo + 2] <= ...
-     *
+     * <p>
      * or the longest descending sequence with:
-     *
+     * <p>
      * a[lo] >  a[lo + 1] >  a[lo + 2] >  ...
-     *
+     * <p>
      * For its intended use in a stable mergesort, the strictness of the
      * definition of "descending" is needed so that the call can safely
      * reverse a descending sequence without violating stability.
@@ -390,14 +391,14 @@ public class FasterFinnSort<T> {
      * Returns the minimum acceptable run length for an array of the specified
      * length. Natural runs shorter than this will be extended with
      * {@link #binarySort}.
-     *
+     * <p>
      * Roughly speaking, the computation is:
-     *
+     * <p>
      * If n < MIN_MERGE, return n (it's too small to bother with fancy stuff).
      * Else if n is an exact power of 2, return MIN_MERGE/2.
      * Else return an int k, MIN_MERGE/2 <= k <= MIN_MERGE, such that n/k
      * is close to, but strictly less than, an exact power of 2.
-     *
+     * <p>
      * For the rationale, see listsort.txt.
      *
      * @param n the length of the array to be sorted
@@ -419,24 +420,24 @@ public class FasterFinnSort<T> {
      * @param runBase index of the first element in the run
      * @param runLen  the number of elements in the run
      */
-    private void pushRun(int runBase, int runLen, int rangeSize) {
+    private void pushRun(int runBase, int runLen) {
         this.runBase[stackSize] = runBase;
         this.runLen[stackSize] = runLen;
-        this.runPower[stackSize] = power(stackSize, rangeSize);
+        this.runPower[stackSize] = power(stackSize);
         stackSize++;
     }
 
     /**
      * Examines the stack of runs waiting to be merged and merges adjacent runs
      * until the stack invariants are reestablished:
-     *
+     * <p>
      * 1. runLen[i - 3] > runLen[i - 2] + runLen[i - 1]
      * 2. runLen[i - 2] > runLen[i - 1]
-     *
+     * <p>
      * This method is called each time a new run is pushed onto the stack,
      * so the invariants are guaranteed to hold for i < stackSize upon
      * entry to the method.
-     *
+     * <p>
      * Thanks to Stijn de Gouw, Jurriaan Rot, Frank S. de Boer,
      * Richard Bubel and Reiner Hahnle, this is fixed with respect to
      * the analysis in "On the Worst-Case Complexity of TimSort" by
@@ -444,16 +445,35 @@ public class FasterFinnSort<T> {
      */
     private void mergeCollapse() {
         while (stackSize > 1) {
-            int n = stackSize - 2;
+            if (runPower[stackSize - 1] < runPower[stackSize - 2]) {
-            if (n > 0 && runPower[n + 1] < runPower[n]) {
+                mergeAt(stackSize - 3);
-                mergeAt(n);
             } else {
                 break; // Invariant is established
             }
         }
     }
-
+/*
-    private int power(int stackSize, int rangeSize) {
+    private int power(int stackSize) {
+        if (stackSize == 0) {
+            return 0;
+        }
+        // int = (right - left + 1); = RangeSize
+        long l = runLen[stackSize - 1]; // + (long) runBase[stackSize]; // - ((long) left << 1); // 2*middleA
+        long r = runLen[stackSize]; // - ((long) left << 1); // 2*middleB
+        int a = (int) ((l << 30) / rangeSize); // middleA / 2n
+        int b = (int) ((r << 30) / rangeSize); // middleB / 2n
+        return Integer.numberOfLeadingZeros(a ^ b);
+    }
+*/
+    private int power(int stackSize) {
+        /*
+        System.out.println(Arrays.toString(runBase));
+        System.out.println(Arrays.toString(runLen));
+        System.out.println(Arrays.toString(runPower));
+        System.out.println(stackSize);
+        System.out.println(rangeSize);
+        System.out.println();
+        */
         if (stackSize == 0)
             return 0;
 
@@ -465,18 +485,50 @@ public class FasterFinnSort<T> {
 
         int result = 0;
 
-        while (b < rangeSize) {
+        while (true) {
             ++result;
             if (a >= rangeSize) {
                 a -= rangeSize;
                 b -= rangeSize;
             }
+            if (b >= rangeSize) {
+                break;
+            }
             a <<= 1;
             b <<= 1;
         }
         return result;
     }
 
+/*
+    public int power(int stackSize) {
+
+        System.out.println(Arrays.toString(runBase));
+        System.out.println(Arrays.toString(runLen));
+        System.out.println(Arrays.toString(runPower));
+        System.out.println(stackSize);
+        System.out.println(rangeSize);
+        System.out.println();
+
+
+        if (stackSize == 0)
+            return 0;
+
+        int n_1 = this.runLen[stackSize - 1];
+        int n_2 = this.runLen[stackSize];
+
+        double a = ((double) this.runBase[stackSize - 1] + 0.5d * n_1 - 1d) / this.rangeSize;
+        double b = ((double) this.runBase[stackSize] + 0.5d * n_2 - 1d) / this.rangeSize;
+        int l = 0;
+        while ((int) (a * pow(2, l)) == (int) (b * pow(2 ,l))) {
+
+            l++;
+        }
+        return l;
+    }
+    */
+
+
     /*
     Backup mergeCollapse() von TimSort:
 
@@ -519,7 +571,7 @@ public class FasterFinnSort<T> {
     private void mergeAt(int i) {
         assert stackSize >= 2;
         assert i >= 0;
-        assert i == stackSize - 2 || i == stackSize - 3;
+        //assert i == stackSize - 3;
 
         int base1 = runBase[i];
         int len1 = runLen[i];
@@ -533,12 +585,14 @@ public class FasterFinnSort<T> {
          * run now, also slide over the last run (which isn't involved
          * in this merge).  The current run (i+1) goes away in any case.
          */
-        runLen[i] = len1 + len2;
-        if (i == stackSize - 3) {
-            runBase[i + 1] = runBase[i + 2];
-            runLen[i + 1] = runLen[i + 2];
-        }
         stackSize--;
+        runLen[i] = len1 + len2;
+
+        // @TODO: Check power before pushing the run
+        runLen[i + 1] = runLen[i + 2];
+        runBase[i + 1] = runBase[i + 2];
+        runPower[i + 1] = runPower[i + 2];
+        //runPower[i] = power(i);
 
         /*
          * Find where the first element of run2 goes in run1. Prior elements

app/src/main/java/de/uni_marburg/powersort/FinnSort/Run.java

@@ -1,14 +1,16 @@
 package de.uni_marburg.powersort.FinnSort;
 
-class Run {
+public class Run {
-    int start;
+    public int start;
-    int end;
+    public int end;
     int power;
+    public int len;
 
     public Run(int i, int j, int p) {
         start = i;
         end = j;
         power = p;
+        len = end - start;
     }
 
 }

app/src/test/java/de/uni_marburg/powersort/sort/FasterFinnSortTest.java

@@ -1,8 +1,77 @@
 package de.uni_marburg.powersort.sort;
 
+import de.uni_marburg.powersort.FinnSort.FasterFinnSort;
+import de.uni_marburg.powersort.FinnSort.Run;
+import de.uni_marburg.powersort.benchmark.NaturalOrder;
+import org.junit.jupiter.api.Test;
+
+import java.lang.reflect.Method;
+
+import static java.lang.Math.pow;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
 public class FasterFinnSortTest extends AbstractSortTest {
     FasterFinnSortTest() {
         sortAlg = SortEnum.FASTER_FINN_SORT;
     }
 
+    @Test
+    public void testMergeOrder() {
+        Integer[] input = {24,25,26,27,28,21,22,23,18,19,20,4,5,6,7,8,9,10,11,12,13,14,15,16,17,3,1,2};
+        FasterFinnSort.sort(input, 0, input.length, NaturalOrder.INSTANCE,null, 0, 0);
+    }
+    @Test
+    public void powerTest() {
+        Run run1 = new Run(0, 10, 0);
+        Run run2 = new Run(10, 20, 0);
+
+        for (int i = 20; i < 10100; i++) {
+            System.out.println(i);
+            //assertEquals(integerPower(run1, run2, i), power(run1, run2, i));
+            assertEquals(power(run1, run2, i),
+                    power2(run1, run2, i));
+        }
+
+    }
+    private static int integerPower(Run run1, Run run2, int n) {
+
+        int n_1 = run1.len;
+        int n_2 = run2.len;
+
+        int a = 2 * run1.start + n_1 - 1;
+        int b = a + n_1 + n_2;
+
+        int result = 0;
+
+        while (a * pow(2, result) == b * pow(2, result)) {
+            result++;
+        }
+
+        return result;
+    }
+    private static int power(Run run1, Run run2, int n) {
+        /*
+        if (run1.start == 0) {
+            return 0;
+        }
+
+         */
+        int n_1 = run1.end - run1.start;
+        int n_2 = run2.end - run2.start;
+        double a = ((double) run1.start + 0.5d * n_1) / n;
+        double b = ((double) run2.start + 0.5d * n_2) / n;
+        int l = 1;
+        while ((int) (a * pow(2, l)) == (int) (b * pow(2 ,l))) {
+            l++;
+        }
+        return l;
+    }
+
+    private int power2(Run run1, Run run2, int n) {
+        long l = (long) run1.start + (long) run2.start; // 2*middleA
+        long r = (long) run2.start + (long) run2.end + 1; // 2*middleB
+        int a = (int) ((l << 30) / n); // middleA / 2n
+        int b = (int) ((r << 30) / n); // middleB / 2n
+        return Integer.numberOfLeadingZeros(a ^ b);
+    }
 }