package com.imsl.test.example.stat;

import com.imsl.stat.*;
import com.imsl.math.*;

/**
 * <p>Computes the survival curve for units under life-testing.
 * </p>
 * <p>
 * This example illustrates the K-M procedure. Assume 20 units are on life test
 * and 6 failures occur at the following times: 10, 32, 56, 98, 122, and 181
 * hours. There were 4 working units removed from the test for other experiments
 * at the following times: 50, 100, 125, and 150 hours. The remaining 10 working
 * units were removed from the test at 200 hours. The K-M estimates for this
 * life test are: </p>
 *
<p>
 * R(10) = 19/20
 * <br/>R(32) = 19/20 x 18/19
 * <br/>R(56) = 19/20 x 18/19 x 16/17
 * <br/>R(98) = 19/20 x 18/19 x 16/17 x 15/16
 * <br/>R(122) = 19/20 x 18/19 x 16/17 x 15/16 x 13/14
 * <br/>R(181) = 19/20 x 18/19 x 16/17 x 15/16 x 13/14 x 10/11
 * </p>
 *
 *
 * @see <a href="KaplanMeierECDFEx1.java">Code</a>
 * @see <a href="doc-files/KaplanMeierECDFEx1.out">Output</a>
 */

public class KaplanMeierECDFEx1 {

    public static void main(String args[]) {
        double y[] = {
            10.0, 32.0, 56.0, 98.0, 122.0, 181.0, 50.0,
            100.0, 125.0, 150.0, 200.0
        };
        int freq[] = {1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 10};
        int censor[] = {0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1};

        KaplanMeierECDF km = new KaplanMeierECDF(y);
        km.setFrequency(freq);
        km.setCensor(censor);
        double[] fx = km.evaluateCDF();

        int ntimes = km.getNumberOfPoints();
        System.out.println("Number of points = " + ntimes);

        double[] x = km.getTimes();
        PrintMatrix p
                = new PrintMatrix("CDF = 1 - survival of life test subjects");
        p.print(fx);
        p.setTitle("Times of change in CDF");
        p.print(x);
    }
}