test/loops/NavigableSetCheck.java

/**
 * @test
 * @synopsis Times and checks basic set operations
 */
import java.util.*;
import java.io.*;

public class NavigableSetCheck {

    static int absentSize;
    static int absentMask;
    static Integer[] absent;

    static final Integer MISSING = new Integer(Integer.MIN_VALUE);

    static TestTimer timer = new TestTimer();

    static void reallyAssert(boolean b) {
        if (!b) throw new Error("Failed Assertion");
    }

    public static void main(String[] args) throws Exception {
        Class setClass = null;
        int numTests = 50;
        int size = 50000;

        if (args.length > 0) {
            try {
                setClass = Class.forName(args[0]);
            } catch(ClassNotFoundException e) {
                throw new RuntimeException("Class " + args[0] + " not found.");
            }
        }


        if (args.length > 1) 
            numTests = Integer.parseInt(args[1]);

        if (args.length > 2) 
            size = Integer.parseInt(args[2]);

        System.out.println("Testing " + setClass.getName() + " trials: " + numTests + " size: " + size);


        absentSize = 8;
        while (absentSize < size) absentSize <<= 1;
        absentMask = absentSize - 1;
        absent = new Integer[absentSize];

        for (int i = 0; i < absentSize; ++i) 
            absent[i] = new Integer(i * 2);

        Integer[] key = new Integer[size];
        for (int i = 0; i < size; ++i) 
            key[i] = new Integer(i * 2 + 1);


        for (int rep = 0; rep < numTests; ++rep) {
            runTest(newSet(setClass), key);
        }

        TestTimer.printStats();

    }

    static NavigableSet newSet(Class cl) {
        try {
            NavigableSet m = (NavigableSet)cl.newInstance();
            return m;
        } catch(Exception e) {
            throw new RuntimeException("Can't instantiate " + cl + ": " + e);
        }
    }


    static void runTest(NavigableSet s, Integer[] key) {
        shuffle(key);
        int size = key.length;
        long startTime = System.currentTimeMillis();
        test(s, key);
        long time = System.currentTimeMillis() - startTime;
    }

    static void t1(String nm, int n, NavigableSet s, Integer[] key, int expect) {
        int sum = 0;
        int iters = 4;
        timer.start(nm, n * iters);
        for (int j = 0; j < iters; ++j) {
            for (int i = 0; i < n; i++) {
                if (s.contains(key[i])) ++sum;
            }
        }
        timer.finish(); 
        reallyAssert (sum == expect * iters);
    }

    static void t2(String nm, int n, NavigableSet s, Integer[] key, int expect) {
        int sum = 0;
        timer.start(nm, n);
        for (int i = 0; i < n; i++) {
            if (s.remove(key[i])) ++sum;
        }
        timer.finish(); 
        reallyAssert (sum == expect);
    }

    static void t3(String nm, int n, NavigableSet s, Integer[] key, int expect) {
        int sum = 0;
        timer.start(nm, n);
        for (int i = 0; i < n; i++) {
            if (s.add(key[i])) ++sum;
        }
        timer.finish(); 
        reallyAssert (sum == expect);
    }

    static void t4(String nm, int n, NavigableSet s, Integer[] key, int expect) {
        int sum = 0;
        timer.start(nm, n);
        for (int i = 0; i < n; i++) {
            if (s.contains(key[i])) ++sum;
        }
        timer.finish(); 
        reallyAssert (sum == expect);
    }

    static void t5(String nm, int n, NavigableSet s, Integer[] key, int expect) {
        int sum = 0;
        timer.start(nm, n/2);
        for (int i = n-2; i >= 0; i-=2) {
            if (s.remove(key[i])) ++sum;
        }
        timer.finish(); 
        reallyAssert (sum == expect);
    }

    static void t6(String nm, int n, NavigableSet s, Integer[] k1, Integer[] k2) {
        int sum = 0;
        timer.start(nm, n * 2);
        for (int i = 0; i < n; i++) {
            if (s.contains(k1[i])) ++sum;
            if (s.contains(k2[i & absentMask])) ++sum;
        }
        timer.finish(); 
        reallyAssert (sum == n);
    }

    static void t7(String nm, int n, NavigableSet s, Integer[] k1, Integer[] k2) {
        int sum = 0;
        timer.start(nm, n * 2);
        for (int i = 0; i < n; i++) {
            if (s.contains(k1[i])) ++sum;
            if (s.contains(k2[i & absentMask])) ++sum;
        }
        timer.finish(); 
        reallyAssert (sum == n);
    }

    static void t8(String nm, int n, NavigableSet s, Integer[] key, int expect) {
        int sum = 0;
        timer.start(nm, n);
        for (int i = 0; i < n; i++) {
            if (s.contains(key[i])) ++sum;
        }
        timer.finish(); 
        reallyAssert (sum == expect);
    }


    static void higherTest(NavigableSet s) {
        int sum = 0;
        int iters = s.size();
        timer.start("Higher                 ", iters);
        Object e = s.first();
        while (e != null) {
            ++sum;
            e = s.higher(e);
        }
        timer.finish(); 
        reallyAssert (sum == iters);
    }

    static void lowerTest(NavigableSet s) {
        int sum = 0;
        int iters = s.size();
        timer.start("Lower                  ", iters);
        Object e = s.first();
        while (e != null) {
            ++sum;
            e = s.higher(e);
        }
        timer.finish(); 
        reallyAssert (sum == iters);
    }

    static void ceilingTest(NavigableSet s) {
        int sum = 0;
        int iters = s.size();
        if (iters > absentSize) iters = absentSize;
        timer.start("Ceiling                ", iters);
        for (int i = 0; i < iters; ++i) {
            Object e = s.ceiling(absent[i]);
            if (e != null)
                ++sum;
        }
        timer.finish(); 
        reallyAssert (sum == iters);
    }

    static void floorTest(NavigableSet s) {
        int sum = 0;
        int iters = s.size();
        if (iters > absentSize) iters = absentSize;
        timer.start("Floor                  ", iters);
        for (int i = 1; i < iters; ++i) {
            Object e = s.floor(absent[i]);
            if (e != null)
                ++sum;
        }
        timer.finish(); 
        reallyAssert (sum == iters-1);
    }


    static void ktest(NavigableSet s, int size, Integer[] key) {
        timer.start("Contains               ", size);
        int sum = 0;
        for (int i = 0; i < size; i++) {
            if (s.contains(key[i])) ++sum;
        }
        timer.finish(); 
        reallyAssert (sum == size);
    }


    static void ittest1(NavigableSet s, int size) {
        int sum = 0;
        timer.start("Iter Key               ", size);
        for (Iterator it = s.iterator(); it.hasNext(); ) {
            if(it.next() != MISSING)
                ++sum;
        }
        timer.finish(); 
        reallyAssert (sum == size);
    }

    static void ittest(NavigableSet s, int size) {
        ittest1(s, size);
    }

    static void rittest1(NavigableSet s, int size) {
        int sum = 0;
        timer.start("Desc Iter Key          ", size);
        for (Iterator it = s.descendingIterator(); it.hasNext(); ) {
            if(it.next() != MISSING)
                ++sum;
        }
        timer.finish(); 
        reallyAssert (sum == size);
    }

    static void rittest(NavigableSet s, int size) {
        rittest1(s, size);
    }


    static void rtest(NavigableSet s, int size) {
        timer.start("Remove (iterator)      ", size);
        for (Iterator it = s.iterator(); it.hasNext(); ) {
            it.next();
            it.remove();
        }
        timer.finish(); 
    }


    static void dtest(NavigableSet s, int size, Integer[] key) {
        timer.start("Add (addAll)           ", size * 2);
        NavigableSet s2 = null;
        try {
            s2 = (NavigableSet) (s.getClass().newInstance());
            s2.addAll(s);
        }
        catch (Exception e) { e.printStackTrace(); return; }
        timer.finish(); 
    
        timer.start("Iter Equals            ", size * 2);
        boolean eqt = s2.equals(s) && s.equals(s2);
        reallyAssert (eqt);
        timer.finish(); 

        timer.start("Iter HashCode          ", size * 2);
        int shc = s.hashCode();
        int s2hc = s2.hashCode();
        reallyAssert (shc == s2hc);
        timer.finish(); 

        timer.start("Add (present)          ", size);
        s2.addAll(s);
        timer.finish(); 

        t6("Contains               ", size, s2, key, absent);

        boolean as2 = s2.add(absent[absentSize-1]);
        reallyAssert(as2);
        timer.start("Iter Equals            ", size * 2);
        eqt = s2.equals(s) && s.equals(s2);
        if (as2)
            reallyAssert (!eqt);
        timer.finish(); 

        timer.start("Iter HashCode          ", size * 2);
        int s1h = s.hashCode();
        int s2h = s2.hashCode();
        if (as2)
            reallyAssert (s1h != s2h);
        timer.finish(); 

        timer.start("Clear                  ", size);
        s.clear();
        s2.clear();
        timer.finish(); 
        reallyAssert (s2.isEmpty() && s.isEmpty());
    }


    static void test(NavigableSet s, Integer[] key) {
        int size = key.length;

        t3("Add (absent)           ", size, s, key, size);
        t3("Add (present)          ", size, s, key, 0);
        t7("ContainsKey            ", size, s, key, absent);
        t4("ContainsKey            ", size, s, key, size);
        ktest(s, size, key);
        t4("Contains               ", absentSize, s, absent, 0);
        t6("Contains               ", size, s, key, absent);
        t1("Contains (present)     ", size, s, key, size);
        t1("Contains (absent)      ", absentSize, s, absent, 0);
        t2("Remove (absent)        ", absentSize, s, absent, 0);
        t5("Remove (present)       ", size, s, key, size / 2);
        t3("Add (half present)     ", size, s, key, size / 2);

        ittest(s, size);
        rittest(s, size);
        higherTest(s);
        ceilingTest(s);
        floorTest(s);
        lowerTest(s);
        rtest(s, size);

        t4("Contains               ", size, s, key, 0);
        t2("Remove (absent)        ", size, s, key, 0);
        t3("Add (presized)         ", size, s, key, size);
        dtest(s, size, key);
    }

    static class TestTimer {
        private String name;
        private long numOps;
        private long startTime;
        private String cname;

        static final java.util.TreeMap accum = new java.util.TreeMap();
    
        static void printStats() {
            for (Iterator it = accum.entrySet().iterator(); it.hasNext(); ) {
                Map.Entry e = (Map.Entry)(it.next());
                Stats stats = ((Stats)(e.getValue()));
                int n = stats.number;
                double t;
                if (n > 0) 
                    t = stats.sum / n;
                else
                    t = stats.least;
                long nano = Math.round(1000000.0 * t);
                System.out.println(e.getKey() + ": " + nano);
            }
        }
    
        void start(String name, long numOps) {
            this.name = name;
            this.cname = classify();
            this.numOps = numOps;
            startTime = System.currentTimeMillis();
        }
    

        String classify() {
            if (name.startsWith("Contains"))
                return "Contains               ";
            else if (name.startsWith("Add"))
                return "Add                    ";
            else if (name.startsWith("Remove"))
                return "Remove                 ";
            else if (name.startsWith("Iter"))
                return "Iter                   ";
            else 
                return null;
        }

        void finish() {
            long endTime = System.currentTimeMillis();
            long time = endTime - startTime;
            double timePerOp = ((double)time)/numOps;

            Object st = accum.get(name);
            if (st == null)
                accum.put(name, new Stats(timePerOp));
            else {
                Stats stats = (Stats) st;
                stats.sum += timePerOp;
                stats.number++;
                if (timePerOp < stats.least) stats.least = timePerOp;
            }

            if (cname != null) {
                st = accum.get(cname);
                if (st == null)
                    accum.put(cname, new Stats(timePerOp));
                else {
                    Stats stats = (Stats) st;
                    stats.sum += timePerOp;
                    stats.number++;
                    if (timePerOp < stats.least) stats.least = timePerOp;
                }
            }

        }

    }

    static class Stats {
        double sum = 0;
        double least;
        int number = 0;
        Stats(double t) { least = t; }
    }

    static Random rng = new Random();

    static void shuffle(Integer[] keys) {
        int size = keys.length;
        for (int i=size; i>1; i--) {
            int r = rng.nextInt(i);
            Integer t = keys[i-1];
            keys[i-1] = keys[r];
            keys[r] = t;
        }
    }

}

Revision:	1.1
Committed:	Mon May 2 19:19:38 2005 UTC (19 years ago) by dl
Branch:	MAIN
Log Message:	Put misc performance tests into CVS
#	User	Rev	Content
1	dl	1.1	/**
2			* @test
3			* @synopsis Times and checks basic set operations
4			*/
5			import java.util.*;
6			import java.io.*;
7
8			public class NavigableSetCheck {
9
10			static int absentSize;
11			static int absentMask;
12			static Integer[] absent;
13
14			static final Integer MISSING = new Integer(Integer.MIN_VALUE);
15
16			static TestTimer timer = new TestTimer();
17
18			static void reallyAssert(boolean b) {
19			if (!b) throw new Error("Failed Assertion");
20			}
21
22			public static void main(String[] args) throws Exception {
23			Class setClass = null;
24			int numTests = 50;
25			int size = 50000;
26
27			if (args.length > 0) {
28			try {
29			setClass = Class.forName(args[0]);
30			} catch(ClassNotFoundException e) {
31			throw new RuntimeException("Class " + args[0] + " not found.");
32			}
33			}
34
35
36			if (args.length > 1)
37			numTests = Integer.parseInt(args[1]);
38
39			if (args.length > 2)
40			size = Integer.parseInt(args[2]);
41
42			System.out.println("Testing " + setClass.getName() + " trials: " + numTests + " size: " + size);
43
44
45			absentSize = 8;
46			while (absentSize < size) absentSize <<= 1;
47			absentMask = absentSize - 1;
48			absent = new Integer[absentSize];
49
50			for (int i = 0; i < absentSize; ++i)
51			absent[i] = new Integer(i * 2);
52
53			Integer[] key = new Integer[size];
54			for (int i = 0; i < size; ++i)
55			key[i] = new Integer(i * 2 + 1);
56
57
58			for (int rep = 0; rep < numTests; ++rep) {
59			runTest(newSet(setClass), key);
60			}
61
62			TestTimer.printStats();
63
64			}
65
66			static NavigableSet newSet(Class cl) {
67			try {
68			NavigableSet m = (NavigableSet)cl.newInstance();
69			return m;
70			} catch(Exception e) {
71			throw new RuntimeException("Can't instantiate " + cl + ": " + e);
72			}
73			}
74
75
76			static void runTest(NavigableSet s, Integer[] key) {
77			shuffle(key);
78			int size = key.length;
79			long startTime = System.currentTimeMillis();
80			test(s, key);
81			long time = System.currentTimeMillis() - startTime;
82			}
83
84			static void t1(String nm, int n, NavigableSet s, Integer[] key, int expect) {
85			int sum = 0;
86			int iters = 4;
87			timer.start(nm, n * iters);
88			for (int j = 0; j < iters; ++j) {
89			for (int i = 0; i < n; i++) {
90			if (s.contains(key[i])) ++sum;
91			}
92			}
93			timer.finish();
94			reallyAssert (sum == expect * iters);
95			}
96
97			static void t2(String nm, int n, NavigableSet s, Integer[] key, int expect) {
98			int sum = 0;
99			timer.start(nm, n);
100			for (int i = 0; i < n; i++) {
101			if (s.remove(key[i])) ++sum;
102			}
103			timer.finish();
104			reallyAssert (sum == expect);
105			}
106
107			static void t3(String nm, int n, NavigableSet s, Integer[] key, int expect) {
108			int sum = 0;
109			timer.start(nm, n);
110			for (int i = 0; i < n; i++) {
111			if (s.add(key[i])) ++sum;
112			}
113			timer.finish();
114			reallyAssert (sum == expect);
115			}
116
117			static void t4(String nm, int n, NavigableSet s, Integer[] key, int expect) {
118			int sum = 0;
119			timer.start(nm, n);
120			for (int i = 0; i < n; i++) {
121			if (s.contains(key[i])) ++sum;
122			}
123			timer.finish();
124			reallyAssert (sum == expect);
125			}
126
127			static void t5(String nm, int n, NavigableSet s, Integer[] key, int expect) {
128			int sum = 0;
129			timer.start(nm, n/2);
130			for (int i = n-2; i >= 0; i-=2) {
131			if (s.remove(key[i])) ++sum;
132			}
133			timer.finish();
134			reallyAssert (sum == expect);
135			}
136
137			static void t6(String nm, int n, NavigableSet s, Integer[] k1, Integer[] k2) {
138			int sum = 0;
139			timer.start(nm, n * 2);
140			for (int i = 0; i < n; i++) {
141			if (s.contains(k1[i])) ++sum;
142			if (s.contains(k2[i & absentMask])) ++sum;
143			}
144			timer.finish();
145			reallyAssert (sum == n);
146			}
147
148			static void t7(String nm, int n, NavigableSet s, Integer[] k1, Integer[] k2) {
149			int sum = 0;
150			timer.start(nm, n * 2);
151			for (int i = 0; i < n; i++) {
152			if (s.contains(k1[i])) ++sum;
153			if (s.contains(k2[i & absentMask])) ++sum;
154			}
155			timer.finish();
156			reallyAssert (sum == n);
157			}
158
159			static void t8(String nm, int n, NavigableSet s, Integer[] key, int expect) {
160			int sum = 0;
161			timer.start(nm, n);
162			for (int i = 0; i < n; i++) {
163			if (s.contains(key[i])) ++sum;
164			}
165			timer.finish();
166			reallyAssert (sum == expect);
167			}
168
169
170			static void higherTest(NavigableSet s) {
171			int sum = 0;
172			int iters = s.size();
173			timer.start("Higher ", iters);
174			Object e = s.first();
175			while (e != null) {
176			++sum;
177			e = s.higher(e);
178			}
179			timer.finish();
180			reallyAssert (sum == iters);
181			}
182
183			static void lowerTest(NavigableSet s) {
184			int sum = 0;
185			int iters = s.size();
186			timer.start("Lower ", iters);
187			Object e = s.first();
188			while (e != null) {
189			++sum;
190			e = s.higher(e);
191			}
192			timer.finish();
193			reallyAssert (sum == iters);
194			}
195
196			static void ceilingTest(NavigableSet s) {
197			int sum = 0;
198			int iters = s.size();
199			if (iters > absentSize) iters = absentSize;
200			timer.start("Ceiling ", iters);
201			for (int i = 0; i < iters; ++i) {
202			Object e = s.ceiling(absent[i]);
203			if (e != null)
204			++sum;
205			}
206			timer.finish();
207			reallyAssert (sum == iters);
208			}
209
210			static void floorTest(NavigableSet s) {
211			int sum = 0;
212			int iters = s.size();
213			if (iters > absentSize) iters = absentSize;
214			timer.start("Floor ", iters);
215			for (int i = 1; i < iters; ++i) {
216			Object e = s.floor(absent[i]);
217			if (e != null)
218			++sum;
219			}
220			timer.finish();
221			reallyAssert (sum == iters-1);
222			}
223
224
225			static void ktest(NavigableSet s, int size, Integer[] key) {
226			timer.start("Contains ", size);
227			int sum = 0;
228			for (int i = 0; i < size; i++) {
229			if (s.contains(key[i])) ++sum;
230			}
231			timer.finish();
232			reallyAssert (sum == size);
233			}
234
235
236			static void ittest1(NavigableSet s, int size) {
237			int sum = 0;
238			timer.start("Iter Key ", size);
239			for (Iterator it = s.iterator(); it.hasNext(); ) {
240			if(it.next() != MISSING)
241			++sum;
242			}
243			timer.finish();
244			reallyAssert (sum == size);
245			}
246
247			static void ittest(NavigableSet s, int size) {
248			ittest1(s, size);
249			}
250
251			static void rittest1(NavigableSet s, int size) {
252			int sum = 0;
253			timer.start("Desc Iter Key ", size);
254			for (Iterator it = s.descendingIterator(); it.hasNext(); ) {
255			if(it.next() != MISSING)
256			++sum;
257			}
258			timer.finish();
259			reallyAssert (sum == size);
260			}
261
262			static void rittest(NavigableSet s, int size) {
263			rittest1(s, size);
264			}
265
266
267			static void rtest(NavigableSet s, int size) {
268			timer.start("Remove (iterator) ", size);
269			for (Iterator it = s.iterator(); it.hasNext(); ) {
270			it.next();
271			it.remove();
272			}
273			timer.finish();
274			}
275
276
277
278			static void dtest(NavigableSet s, int size, Integer[] key) {
279			timer.start("Add (addAll) ", size * 2);
280			NavigableSet s2 = null;
281			try {
282			s2 = (NavigableSet) (s.getClass().newInstance());
283			s2.addAll(s);
284			}
285			catch (Exception e) { e.printStackTrace(); return; }
286			timer.finish();
287
288			timer.start("Iter Equals ", size * 2);
289			boolean eqt = s2.equals(s) && s.equals(s2);
290			reallyAssert (eqt);
291			timer.finish();
292
293			timer.start("Iter HashCode ", size * 2);
294			int shc = s.hashCode();
295			int s2hc = s2.hashCode();
296			reallyAssert (shc == s2hc);
297			timer.finish();
298
299			timer.start("Add (present) ", size);
300			s2.addAll(s);
301			timer.finish();
302
303			t6("Contains ", size, s2, key, absent);
304
305			boolean as2 = s2.add(absent[absentSize-1]);
306			reallyAssert(as2);
307			timer.start("Iter Equals ", size * 2);
308			eqt = s2.equals(s) && s.equals(s2);
309			if (as2)
310			reallyAssert (!eqt);
311			timer.finish();
312
313			timer.start("Iter HashCode ", size * 2);
314			int s1h = s.hashCode();
315			int s2h = s2.hashCode();
316			if (as2)
317			reallyAssert (s1h != s2h);
318			timer.finish();
319
320			timer.start("Clear ", size);
321			s.clear();
322			s2.clear();
323			timer.finish();
324			reallyAssert (s2.isEmpty() && s.isEmpty());
325			}
326
327
328
329			static void test(NavigableSet s, Integer[] key) {
330			int size = key.length;
331
332			t3("Add (absent) ", size, s, key, size);
333			t3("Add (present) ", size, s, key, 0);
334			t7("ContainsKey ", size, s, key, absent);
335			t4("ContainsKey ", size, s, key, size);
336			ktest(s, size, key);
337			t4("Contains ", absentSize, s, absent, 0);
338			t6("Contains ", size, s, key, absent);
339			t1("Contains (present) ", size, s, key, size);
340			t1("Contains (absent) ", absentSize, s, absent, 0);
341			t2("Remove (absent) ", absentSize, s, absent, 0);
342			t5("Remove (present) ", size, s, key, size / 2);
343			t3("Add (half present) ", size, s, key, size / 2);
344
345			ittest(s, size);
346			rittest(s, size);
347			higherTest(s);
348			ceilingTest(s);
349			floorTest(s);
350			lowerTest(s);
351			rtest(s, size);
352
353			t4("Contains ", size, s, key, 0);
354			t2("Remove (absent) ", size, s, key, 0);
355			t3("Add (presized) ", size, s, key, size);
356			dtest(s, size, key);
357			}
358
359			static class TestTimer {
360			private String name;
361			private long numOps;
362			private long startTime;
363			private String cname;
364
365			static final java.util.TreeMap accum = new java.util.TreeMap();
366
367			static void printStats() {
368			for (Iterator it = accum.entrySet().iterator(); it.hasNext(); ) {
369			Map.Entry e = (Map.Entry)(it.next());
370			Stats stats = ((Stats)(e.getValue()));
371			int n = stats.number;
372			double t;
373			if (n > 0)
374			t = stats.sum / n;
375			else
376			t = stats.least;
377			long nano = Math.round(1000000.0 * t);
378			System.out.println(e.getKey() + ": " + nano);
379			}
380			}
381
382			void start(String name, long numOps) {
383			this.name = name;
384			this.cname = classify();
385			this.numOps = numOps;
386			startTime = System.currentTimeMillis();
387			}
388
389
390			String classify() {
391			if (name.startsWith("Contains"))
392			return "Contains ";
393			else if (name.startsWith("Add"))
394			return "Add ";
395			else if (name.startsWith("Remove"))
396			return "Remove ";
397			else if (name.startsWith("Iter"))
398			return "Iter ";
399			else
400			return null;
401			}
402
403			void finish() {
404			long endTime = System.currentTimeMillis();
405			long time = endTime - startTime;
406			double timePerOp = ((double)time)/numOps;
407
408			Object st = accum.get(name);
409			if (st == null)
410			accum.put(name, new Stats(timePerOp));
411			else {
412			Stats stats = (Stats) st;
413			stats.sum += timePerOp;
414			stats.number++;
415			if (timePerOp < stats.least) stats.least = timePerOp;
416			}
417
418			if (cname != null) {
419			st = accum.get(cname);
420			if (st == null)
421			accum.put(cname, new Stats(timePerOp));
422			else {
423			Stats stats = (Stats) st;
424			stats.sum += timePerOp;
425			stats.number++;
426			if (timePerOp < stats.least) stats.least = timePerOp;
427			}
428			}
429
430			}
431
432			}
433
434			static class Stats {
435			double sum = 0;
436			double least;
437			int number = 0;
438			Stats(double t) { least = t; }
439			}
440
441			static Random rng = new Random();
442
443			static void shuffle(Integer[] keys) {
444			int size = keys.length;
445			for (int i=size; i>1; i--) {
446			int r = rng.nextInt(i);
447			Integer t = keys[i-1];
448			keys[i-1] = keys[r];
449			keys[r] = t;
450			}
451			}
452
453			}
454