Example usage for java.util Random nextFloat

Introduction

In this page you can find the example usage for java.util Random nextFloat.

Prototype

public float nextFloat() 

Source Link

Document

Returns the next pseudorandom, uniformly distributed float value between 0.0 and 1.0 from this random number generator's sequence.

Usage

From source file:Main.java

/**
 * Fills the array with random floats.  Values will be between min (inclusive) and
 * max (inclusive).//from ww  w . j a  va2  s. co  m
 */
public static void genRandomFloats(long seed, float min, float max, float array[], boolean includeExtremes) {
    Random r = new Random(seed);
    int minExponent = Math.min(Math.getExponent(min), 0);
    int maxExponent = Math.max(Math.getExponent(max), 0);
    if (minExponent < -6 || maxExponent > 6) {
        // Use an exponential distribution
        int exponentDiff = maxExponent - minExponent;
        for (int i = 0; i < array.length; i++) {
            float mantissa = r.nextFloat();
            int exponent = minExponent + r.nextInt(maxExponent - minExponent);
            int sign = (min >= 0) ? 1 : 1 - r.nextInt(2) * 2; // -1 or 1
            float rand = sign * mantissa * (float) Math.pow(2.0, exponent);
            if (rand < min || rand > max) {
                continue;
            }
            array[i] = rand;
        }
    } else {
        // Use a linear distribution
        for (int i = 0; i < array.length; i++) {
            float rand = r.nextFloat();
            array[i] = min + rand * (max - min);
        }
    }
    // Seed a few special numbers we want to be sure to test.
    for (int i = 0; i < sInterestingDoubles.length; i++) {
        float f = (float) sInterestingDoubles[i];
        if (min <= f && f <= max) {
            array[r.nextInt(array.length)] = f;
        }
    }
    array[r.nextInt(array.length)] = min;
    array[r.nextInt(array.length)] = max;
    if (includeExtremes) {
        array[r.nextInt(array.length)] = Float.NaN;
        array[r.nextInt(array.length)] = Float.POSITIVE_INFINITY;
        array[r.nextInt(array.length)] = Float.NEGATIVE_INFINITY;
        array[r.nextInt(array.length)] = Float.MIN_VALUE;
        array[r.nextInt(array.length)] = Float.MIN_NORMAL;
        array[r.nextInt(array.length)] = Float.MAX_VALUE;
        array[r.nextInt(array.length)] = -Float.MIN_VALUE;
        array[r.nextInt(array.length)] = -Float.MIN_NORMAL;
        array[r.nextInt(array.length)] = -Float.MAX_VALUE;
    }
}

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From source file:edu.berkeley.sparrow.examples.ProtoBackend.java

/**
 * Benchmark that runs random floating point multiplications for the specified amount of
 * "iterations", where each iteration is one millisecond.
 *///  w ww .  j  a va2  s  .  c  o  m
public static void runFloatingPointBenchmark(int iterations, Random r) {
    int runtimeMillis = iterations;
    long startTime = System.nanoTime();
    int opsPerIteration = 1000;
    /* We keep a running result here and print it out so that the JVM doesn't
     * optimize all this computation away. */
    float result = r.nextFloat();
    while ((System.nanoTime() - startTime) / (1000.0 * 1000.0) < runtimeMillis) {
        for (int j = 0; j < opsPerIteration; j++) {
            // On each iteration, perform a floating point multiplication
            float x = r.nextFloat();
            float y = r.nextFloat();
            result += (x * y);
        }
    }
    LOG.debug("Benchmark result " + result);
}

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From source file:org.wso2.carbon.sample.performance.Client.java

private static void sendWarmUpEvents(DataPublisher dataPublisher, long warmUpCount) {
    long counter = 0;
    Random randomGenerator = new Random();
    String streamId = "org.wso2.event.sensor.stream:1.0.0";

    while (counter < warmUpCount) {
        boolean isPowerSaveEnabled = randomGenerator.nextBoolean();
        int sensorId = randomGenerator.nextInt();
        double longitude = randomGenerator.nextDouble();
        double latitude = randomGenerator.nextDouble();
        float humidity = randomGenerator.nextFloat();
        double sensorValue = randomGenerator.nextDouble();
        Event event = new Event(streamId, System.currentTimeMillis(),
                new Object[] { System.currentTimeMillis(), isPowerSaveEnabled, sensorId, "warmup-" + counter },
                new Object[] { longitude, latitude }, new Object[] { humidity, sensorValue });

        dataPublisher.publish(event);/*from   w w  w . j  a  v a2  s .  c  o m*/
        counter++;
    }
}

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From source file:hivemall.mix.server.MixServerTest.java

private static void invokeClient01(String groupId, int serverPort, boolean denseModel, boolean cancelMix)
        throws InterruptedException {
    PredictionModel model = denseModel ? new DenseModel(100, false) : new SparseModel(100, false);
    model.configureClock();//  w  ww .  ja v  a  2  s .  c  o m
    MixClient client = null;
    try {
        client = new MixClient(MixEventName.average, groupId, "localhost:" + serverPort, false, 3, model);
        model.configureMix(client, cancelMix);

        final Random rand = new Random(43);
        for (int i = 0; i < 1000000; i++) {
            Integer feature = Integer.valueOf(rand.nextInt(100));
            float weight = rand.nextFloat() >= 0.5f ? 1.f : 0.f;
            model.set(feature, new WeightValue(weight));
        }

        waitForMixed(model, 100000L, 10000L);

        long numMixed = model.getNumMixed();
        Assert.assertTrue("number of mix events: " + numMixed, numMixed > 0);

        for (int i = 0; i < 100; i++) {
            float w = model.getWeight(i);
            Assert.assertEquals(0.5f, w, 0.1f);
        }
    } finally {
        IOUtils.closeQuietly(client);
    }
}

---

From source file:org.wso2.carbon.sample.performance.Client.java

private static void publishEventsForLatency(DataPublisher dataPublisher, long eventCount, long elapsedCount,
        long warmUpCount) {
    sendWarmUpEvents(dataPublisher, warmUpCount);
    long counter = 0;
    Random randomGenerator = new Random();
    String streamId = "org.wso2.event.sensor.stream:1.0.0";

    while (counter < eventCount) {
        boolean isPowerSaveEnabled = randomGenerator.nextBoolean();
        int sensorId = randomGenerator.nextInt();
        double longitude = randomGenerator.nextDouble();
        double latitude = randomGenerator.nextDouble();
        float humidity = randomGenerator.nextFloat();
        double sensorValue = randomGenerator.nextDouble();
        Event event = new Event(streamId, System.currentTimeMillis(),
                new Object[] { System.currentTimeMillis(), isPowerSaveEnabled, sensorId,
                        "temperature-" + counter },
                new Object[] { longitude, latitude }, new Object[] { humidity, sensorValue });

        dataPublisher.publish(event);//  www .ja  va  2 s .  co  m
        log.info("Sent event " + counter + " at " + System.currentTimeMillis());

        if (elapsedCount > 0) {
            try {
                Thread.sleep(elapsedCount);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        counter++;
    }
}

---

From source file:com.linkedin.pinot.core.segment.index.creator.RawIndexCreatorTest.java

/**
 * Helper method that generates a random value for a given data type
 *
 * @param dataType Data type for which to generate the random value
 * @return Random value for the data type.
 */// w  w  w .  j a va  2  s.co m
public static Object getRandomValue(Random random, FieldSpec.DataType dataType) {
    Object value;
    switch (dataType) {
    case INT:
        value = random.nextInt();
        break;

    case LONG:
        value = random.nextLong();
        break;

    case FLOAT:
        value = random.nextFloat();
        break;

    case DOUBLE:
        value = random.nextDouble();
        break;

    case STRING:
        value = StringUtil
                .trimTrailingNulls(RandomStringUtils.random(random.nextInt(MAX_STRING_LENGTH_IN_BYTES)));
        break;

    default:
        throw new IllegalArgumentException("Illegal data type for random value generator: " + dataType);
    }
    return value;
}

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From source file:com.esri.arcgis.android.samples.nearby.Nearby.java

private static String getRating() {
    // Randomized ratings could be replaced by a ratings service from a third
    // party./*from   w ww . j  av a  2s  .c  o m*/
    Random r = new Random();
    return String.valueOf(1 + (r.nextFloat() * 4));
}

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From source file:com.rbsoftware.pfm.personalfinancemanager.utils.Utils.java

/**
 * Generates random alphanumeric string//from  ww  w. ja v a2  s .  c  o  m
 *
 * @param length of string
 * @return random string
 */
public static String generateRandomString(int length) {
    String SALTCHARS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvmxyz1234567890";
    StringBuilder salt = new StringBuilder();
    Random rnd = new Random();
    while (salt.length() < length) {
        int index = (int) (rnd.nextFloat() * SALTCHARS.length());
        salt.append(SALTCHARS.charAt(index));
    }
    return salt.toString();

}

---

From source file:org.wso2.carbon.sample.performance.Client.java

private static void publishEvents(DataPublisher dataPublisher, long eventCount, long elapsedCount,
        long warmUpCount) {
    long counter = 0;
    Random randomGenerator = new Random();
    String streamId = "org.wso2.event.sensor.stream:1.0.0";
    long lastTime = System.currentTimeMillis();
    DecimalFormat decimalFormat = new DecimalFormat("#");

    while (counter < eventCount) {
        boolean isPowerSaveEnabled = randomGenerator.nextBoolean();
        int sensorId = randomGenerator.nextInt();
        double longitude = randomGenerator.nextDouble();
        double latitude = randomGenerator.nextDouble();
        float humidity = randomGenerator.nextFloat();
        double sensorValue = randomGenerator.nextDouble();
        Event event = new Event(streamId, System.currentTimeMillis(),
                new Object[] { System.currentTimeMillis(), isPowerSaveEnabled, sensorId,
                        "temperature-" + counter },
                new Object[] { longitude, latitude }, new Object[] { humidity, sensorValue });

        dataPublisher.publish(event);//www. j av  a 2s .  c  om

        if ((counter > warmUpCount) && ((counter + 1) % elapsedCount == 0)) {

            long currentTime = System.currentTimeMillis();
            long elapsedTime = currentTime - lastTime;
            double throughputPerSecond = (((double) elapsedCount) / elapsedTime) * 1000;
            lastTime = currentTime;
            log.info("Sent " + elapsedCount + " sensor events in " + elapsedTime
                    + " milliseconds with total throughput of " + decimalFormat.format(throughputPerSecond)
                    + " events per second.");
        }

        counter++;
    }
}

---

From source file:org.apache.druid.segment.IndexMergerV9WithSpatialIndexTest.java

private static IncrementalIndex makeIncrementalIndex() throws IOException {
    IncrementalIndex theIndex = new IncrementalIndex.Builder()
            .setIndexSchema(/*  w  w  w. j a va2s.  c  o  m*/
                    new IncrementalIndexSchema.Builder().withMinTimestamp(DATA_INTERVAL.getStartMillis())
                            .withQueryGranularity(Granularities.DAY).withMetrics(METRIC_AGGS)
                            .withDimensionsSpec(new DimensionsSpec(null, null, Arrays.asList(
                                    new SpatialDimensionSchema("dim.geo", Arrays.asList("lat", "long")),
                                    new SpatialDimensionSchema("spatialIsRad", Arrays.asList("lat2", "long2"))

                            ))).build()).setReportParseExceptions(false).setMaxRowCount(NUM_POINTS)
            .buildOnheap();

    theIndex.add(new MapBasedInputRow(DateTimes.of("2013-01-01").getMillis(), DIMS, ImmutableMap.of("timestamp",
            DateTimes.of("2013-01-01").toString(), "dim", "foo", "lat", 0.0f, "long", 0.0f, "val", 17L)));
    theIndex.add(new MapBasedInputRow(DateTimes.of("2013-01-02").getMillis(), DIMS, ImmutableMap.of("timestamp",
            DateTimes.of("2013-01-02").toString(), "dim", "foo", "lat", 1.0f, "long", 3.0f, "val", 29L)));
    theIndex.add(new MapBasedInputRow(DateTimes.of("2013-01-03").getMillis(), DIMS, ImmutableMap.of("timestamp",
            DateTimes.of("2013-01-03").toString(), "dim", "foo", "lat", 4.0f, "long", 2.0f, "val", 13L)));
    theIndex.add(new MapBasedInputRow(DateTimes.of("2013-01-04").getMillis(), DIMS, ImmutableMap.of("timestamp",
            DateTimes.of("2013-01-04").toString(), "dim", "foo", "lat", 7.0f, "long", 3.0f, "val", 91L)));
    theIndex.add(new MapBasedInputRow(DateTimes.of("2013-01-05").getMillis(), DIMS, ImmutableMap.of("timestamp",
            DateTimes.of("2013-01-05").toString(), "dim", "foo", "lat", 8.0f, "long", 6.0f, "val", 47L)));
    theIndex.add(new MapBasedInputRow(DateTimes.of("2013-01-05").getMillis(), DIMS,
            ImmutableMap.of("timestamp", DateTimes.of("2013-01-05").toString(), "dim", "foo", "lat",
                    "_mmx.unknown", "long", "_mmx.unknown", "val", 101L)));
    theIndex.add(new MapBasedInputRow(DateTimes.of("2013-01-05").getMillis(), DIMS, ImmutableMap.of("timestamp",
            DateTimes.of("2013-01-05").toString(), "dim", "foo", "dim.geo", "_mmx.unknown", "val", 501L)));
    theIndex.add(new MapBasedInputRow(DateTimes.of("2013-01-05").getMillis(), DIMS, ImmutableMap.of("timestamp",
            DateTimes.of("2013-01-05").toString(), "lat2", 0.0f, "long2", 0.0f, "val", 13L)));

    // Add a bunch of random points
    Random rand = ThreadLocalRandom.current();
    for (int i = 8; i < NUM_POINTS; i++) {
        theIndex.add(new MapBasedInputRow(DateTimes.of("2013-01-01").getMillis(), DIMS,
                ImmutableMap.of("timestamp", DateTimes.of("2013-01-01").toString(), "dim", "boo", "lat",
                        (float) (rand.nextFloat() * 10 + 10.0), "long", (float) (rand.nextFloat() * 10 + 10.0),
                        "val", i)));
    }

    return theIndex;
}

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