Examples with ChiSquare cern.jet.random.ChiSquare used on opensource projects

Example 1 with ChiSquare

use of cern.jet.random.ChiSquare in project voldemort by voldemort.

the class ConsistentRoutingStrategyTest method assertWellBalanced.

private void assertWellBalanced(int numNodes, Multiset<Integer> ids) {
    // compute the chi-sq statistic
    double expected = ids.size() / (double) numNodes;
    double chiSq = 0.0;
    int df = numNodes - 1;
    NumberFormat prct = NumberFormat.getPercentInstance();
    prct.setMaximumFractionDigits(4);
    NumberFormat num = NumberFormat.getInstance();
    num.setMaximumFractionDigits(4);
    num.setMinimumFractionDigits(4);
    System.out.println("node\treqs\tX^2\tskew");
    for (Integer id : ids.elementSet()) {
        System.out.println(id + "\t" + ids.count(id) + "\t" + num.format(chiSq(ids.count(id), expected)) + "\t" + prct.format((ids.count(id) - expected) / expected));
        chiSq += chiSq(ids.count(id), expected);
    }
    System.out.println("X^2 = " + chiSq);
    ChiSquare dist = new ChiSquare(df, new MersenneTwister());
    // p-value is ~= prob of seeing this distribution from fair router
    double pValue = 1.0 - dist.cdf(chiSq);
    System.out.println("p-value = " + pValue);
    assertTrue("Non-uniform load distribution detected.", pValue >= 0.05);
}

Example 2 with ChiSquare

use of cern.jet.random.ChiSquare in project processdash by dtuma.

the class LognormalConfidenceInterval method generateBootstrapSamples.

private double[] generateBootstrapSamples() {
    RandomEngine u = new MersenneTwister();
    Normal normal = new Normal(0, 1, u);
    ChiSquare chisquare = new ChiSquare(numSamples - 1, u);
    int bootstrapSize = Settings.getInt("logCI.bootstrapSize", 2000);
    double[] samples = new double[bootstrapSize];
    for (int i = bootstrapSize; i-- > 0; ) samples[i] = generateBootstrapSample(normal, chisquare, numSamples, logstd);
    Arrays.sort(samples);
    return samples;
}