Example usage for org.apache.commons.math.distribution ZipfDistributionImpl inverseCumulativeProbability

Introduction

In this page you can find the example usage for org.apache.commons.math.distribution ZipfDistributionImpl inverseCumulativeProbability.

Prototype

public int inverseCumulativeProbability(final double p) throws MathException 

Source Link

Document

For a random variable X whose values are distributed according to this distribution, this method returns the largest x, such that P(X ≤ x) ≤ p.

Usage

From source file:org.apache.accumulo.test.randomwalk.conditional.Transfer.java

@Override
public void visit(State state, Environment env, Properties props) throws Exception {
    String table = state.getString("tableName");
    Random rand = (Random) state.get("rand");
    Connector conn = env.getConnector();

    int numAccts = (Integer) state.get("numAccts");
    // note: non integer exponents are slow

    ZipfDistributionImpl zdiBanks = new ZipfDistributionImpl((Integer) state.get("numBanks"), 1);
    String bank = Utils.getBank(zdiBanks.inverseCumulativeProbability(rand.nextDouble()));
    ZipfDistributionImpl zdiAccts = new ZipfDistributionImpl(numAccts, 1);
    String acct1 = Utils.getAccount(zdiAccts.inverseCumulativeProbability(rand.nextDouble()));
    String acct2 = Utils.getAccount(zdiAccts.inverseCumulativeProbability(rand.nextDouble()));
    while (acct2.equals(acct1)) {
        // intentionally not using zipf distribution to pick on retry
        acct2 = Utils.getAccount(rand.nextInt(numAccts));
    }/*from   w  ww.  j a v  a  2s .  c o m*/

    // TODO document how data should be read when using ConditionalWriter
    Scanner scanner = new IsolatedScanner(conn.createScanner(table, Authorizations.EMPTY));

    scanner.setRange(new Range(bank));
    scanner.fetchColumnFamily(new Text(acct1));
    scanner.fetchColumnFamily(new Text(acct2));

    Account a1 = new Account();
    Account a2 = new Account();
    Account a;

    for (Entry<Key, Value> entry : scanner) {
        String cf = entry.getKey().getColumnFamilyData().toString();
        String cq = entry.getKey().getColumnQualifierData().toString();

        if (cf.equals(acct1))
            a = a1;
        else if (cf.equals(acct2))
            a = a2;
        else
            throw new Exception("Unexpected column fam: " + cf);

        if (cq.equals("bal"))
            a.setBal(entry.getValue().toString());
        else if (cq.equals("seq"))
            a.setSeq(entry.getValue().toString());
        else
            throw new Exception("Unexpected column qual: " + cq);
    }

    int amt = rand.nextInt(50);

    log.debug("transfer req " + bank + " " + amt + " " + acct1 + " " + a1 + " " + acct2 + " " + a2);

    if (a1.bal >= amt) {
        ConditionalMutation cm = new ConditionalMutation(bank,
                new Condition(acct1, "seq").setValue(Utils.getSeq(a1.seq)),
                new Condition(acct2, "seq").setValue(Utils.getSeq(a2.seq)));
        cm.put(acct1, "bal", (a1.bal - amt) + "");
        cm.put(acct2, "bal", (a2.bal + amt) + "");
        cm.put(acct1, "seq", Utils.getSeq(a1.seq + 1));
        cm.put(acct2, "seq", Utils.getSeq(a2.seq + 1));

        ConditionalWriter cw = (ConditionalWriter) state.get("cw");
        Status status = cw.write(cm).getStatus();
        while (status == Status.UNKNOWN) {
            log.debug("retrying transfer " + status);
            status = cw.write(cm).getStatus();
        }
        log.debug("transfer result " + bank + " " + status + " " + a1 + " " + a2);
    }

}

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