Examples of java.util.Random

java.util.Random
An instance of this class is used to generate a stream of pseudorandom numbers. The class uses a 48-bit seed, which is modified using a linear congruential formula. (See Donald Knuth, The Art of Computer Programming, Volume 3, Section 3.2.1.)
If two instances of {@code Random} are created with the sameseed, and the same sequence of method calls is made for each, they will generate and return identical sequences of numbers. In order to guarantee this property, particular algorithms are specified for the class {@code Random}. Java implementations must use all the algorithms shown here for the class {@code Random}, for the sake of absolute portability of Java code. However, subclasses of class {@code Random}are permitted to use other algorithms, so long as they adhere to the general contracts for all the methods.
The algorithms implemented by class {@code Random} use a{@code protected} utility method that on each invocation can supplyup to 32 pseudorandomly generated bits.
Many applications will find the method {@link Math#random} simpler to use. @author Frank Yellin @version 1.47, 02/07/06 @since 1.0

        testSetFast(used, true);
    }


    private void testSetFast(BitField used, boolean init) {
        int len = 10000;
        Random random = new Random(1);
        for (int i = 0, x = 0; i < len / 8; i++) {
            int mask = random.nextInt() & 255;
            if (init) {
                assertEquals(mask, used.getByte(x));
                x += 8;
                // for (int j = 0; j < 8; j++, x++) {
                // if (used.get(x) != ((mask & (1 << j)) != 0)) {

View Full Code Here

    private void testRandom() {
        BitField bits = new BitField();
        BitSet set = new BitSet();
        int max = 300;
        int count = 100000;
        Random random = new Random(1);
        for (int i = 0; i < count; i++) {
            int idx = random.nextInt(max);
            if (random.nextBoolean()) {
                if (random.nextBoolean()) {
                    bits.set(idx);
                    set.set(idx);
                } else {
                    bits.clear(idx);
                    set.clear(idx);

View Full Code Here

    }


    private void testRandomSetRange() {
        BitField bits = new BitField();
        BitSet set = new BitSet();
        Random random = new Random(1);
        int maxOffset = 500;
        int maxLen = 500;
        int total = maxOffset + maxLen;
        int count = 10000;
        for (int i = 0; i < count; i++) {
            int offset = random.nextInt(maxOffset);
            int len = random.nextInt(maxLen);
            boolean val = random.nextBoolean();
            set.set(offset, offset + len, val);
            bits.set(offset, offset + len, val);
            for (int j = 0; j < total; j++) {
                assertEquals(set.get(j), bits.get(j));
            }

View Full Code Here

        prep.execute();
    }


    private static String getString(int id) {
        StringBuilder buff = new StringBuilder();
        Random rnd = new Random(id);
        int len = rnd.nextInt(40);
        for (int i = 0; i < len; i++) {
            String s = "bcdfghklmnprstwz";
            char c = s.charAt(rnd.nextInt(s.length()));
            buff.append(i == 0 ? Character.toUpperCase(c) : c);
            s = "aeiou  ";


            buff.append(s.charAt(rnd.nextInt(s.length())));
        }
        return buff.toString();
    }

View Full Code Here

        testRandom();
    }


    private void testRandom() {
        int len = getSize(1000, 10000);
        Random random = new Random(10);
        for (int i = 0; i < len; i++) {
            int l = random.nextInt(10);
            String[] sql = new String[l];
            StringBuilder buff = new StringBuilder();
            for (int j = 0; j < l; j++) {
                sql[j] = randomStatement(random);
                buff.append(sql[j]);

View Full Code Here

        assertEquals(10, m.interleave(0, 3));
        assertEquals(10, m.interleave(new int[] { 0, 3 }));
        long v = Integer.MAX_VALUE | ((long) Integer.MAX_VALUE << 31L);
        assertEquals(v, m.interleave(Integer.MAX_VALUE, Integer.MAX_VALUE));
        assertEquals(v, m.interleave(new int[] { Integer.MAX_VALUE, Integer.MAX_VALUE }));
        Random random = new Random(1);
        for (int i = 0; i < 1000; i++) {
            int x = random.nextInt(Integer.MAX_VALUE), y = random.nextInt(Integer.MAX_VALUE);
            v = m.interleave(new int[] {x, y});
            long v2 = m.interleave(x, y);
            assertEquals(v, v2);
            int x1 = m.deinterleave(2, v, 0);
            int y1 = m.deinterleave(2, v, 1);
            assertEquals(x, x1);
            assertEquals(y, y1);
        }
        for (int i = 0; i < 1000; i++) {
            int x = random.nextInt(1000), y = random.nextInt(1000), z = random.nextInt(1000);
            MultiDimension tool = MultiDimension.getInstance();
            long xyz = tool.interleave(new int[] { x, y, z });
            assertEquals(x, tool.deinterleave(3, xyz, 0));
            assertEquals(y, tool.deinterleave(3, xyz, 1));
            assertEquals(z, tool.deinterleave(3, xyz, 2));

View Full Code Here

        String sql = multi.generatePreparedQuery("TEST", "XY", new String[] { "X", "Y" });
        sql += " ORDER BY X, Y";
        PreparedStatement prepMulti = conn.prepareStatement(sql);
        long timeMulti = 0, timeRegular = 0;
        int timeMax = getSize(500, 2000);
        Random rand = new Random(1);
        for (int i = 0; timeMulti < timeMax; i++) {
            int size = rand.nextInt(max / 10);
            int minX = rand.nextInt(max - size);
            int minY = rand.nextInt(max - size);
            int maxX = minX + size, maxY = minY + size;
            time = System.currentTimeMillis();
            ResultSet rs1 = multi.getResult(prepMulti, new int[] { minX, minY }, new int[] { maxX, maxY });
            timeMulti += System.currentTimeMillis() - time;
            time = System.currentTimeMillis();

View Full Code Here

        String sql = multi.generatePreparedQuery("TEST", "XYZ", new String[] { "X", "Y", "Z" });
        sql += " ORDER BY X, Y, Z";
        PreparedStatement prepMulti = conn.prepareStatement(sql);
        long timeMulti = 0, timeRegular = 0;
        int timeMax = getSize(500, 2000);
        Random rand = new Random(1);
        for (int i = 0; timeMulti < timeMax; i++) {
            int size = rand.nextInt(max / 10);
            int minX = rand.nextInt(max - size);
            int minY = rand.nextInt(max - size);
            int minZ = rand.nextInt(max - size);
            int maxX = minX + size, maxY = minY + size, maxZ = minZ + size;
            time = System.currentTimeMillis();
            ResultSet rs1 = multi.getResult(prepMulti, new int[] { minX, minY, minZ }, new int[] { maxX, maxY, maxZ });
            timeMulti += System.currentTimeMillis() - time;
            time = System.currentTimeMillis();

View Full Code Here


    private static void runBenchmarkWithZipfDistributionLock(Status stat, ILock lock, FixedSegments pager, ConcurrentPluggableCache<Long, byte[]> cache, int capacity, int round, double percent, int scanLength, long[] dist) {
        boolean scanning = false;
        long scanCount = 0L;


        final Random rand = new Random();


        int scanned = 0, zipf = 0;
        long base = 0L;


        long mills1 = System.currentTimeMillis();
        long ops = 0L;
        long miss = 0L;


        long totalExecInterval = 0L, totalDurationHold = 0L;
        long prelock = System.currentTimeMillis();


        final int limit = round - 1;
        for(int nth = 0, i = 0; !_stop; nth = (nth >= limit) ? 0 : nth + 1, i++) {
            final long key;
            if(scanning || scanLength != 0 && (i == scanLength && rand.nextDouble() < percent)) {
                if(++scanCount <= scanLength) {
                    if(!scanning) {
                        base = dist[nth];
                    }
                    key = base + scanCount;

View Full Code Here


    private static void runBenchmarkWithZipfDistributionReadWriteLock(ReadWriteLock rwlock, Status stat, FixedSegments pager, ConcurrentPluggableCache<Long, byte[]> cache, int capacity, int round, double percent, int scanLength, long[] dist) {
        boolean scanning = false;
        long scanCount = 0L;


        final Random rand = new Random();


        int scanned = 0, zipf = 0;
        long base = 0L;


        long mills1 = System.currentTimeMillis();
        long ops = 0L;
        long miss = 0L;


        final Lock readLock = rwlock.readLock();
        final Lock writeLock = rwlock.writeLock();


        final int limit = round - 1;
        for(int nth = 0, i = 0; !_stop; nth = (nth >= limit) ? 0 : nth + 1, i++) {
            final long key;
            if(scanning || scanLength != 0 && (i == scanLength && rand.nextDouble() < percent)) {
                if(++scanCount <= scanLength) {
                    if(!scanning) {
                        base = dist[nth];
                    }
                    key = base + scanCount;

View Full Code Here

0 1 2 3 4 5 6 7 8 9

TOP

Related Classes of java.util.Random

cc.mallet.fst.CRFTrainerByLabelLikelihood

cc.mallet.fst.tests.TestCRF

cc.mallet.grmm.test.TestInference

cc.mallet.grmm.test.TestRandomGraphs

ch.akuhn.util.Get

com.bericotech.clavin.util.DamerauLevenshteinTest

com.browseengine.bobo.util.test.MutableSparseFloatArrayTest

com.codetutr.service.PersonServiceImpl

com.esotericsoftware.kryo.InputOutputTest

com.esotericsoftware.kryo.UnsafeInputOutputTest

All source code are property of their respective owners. Java is a trademark of Sun Microsystems, Inc and owned by ORACLE Inc. Contact coftware#gmail.com.