[jira] [Resolved] (KYLIN-3306) Fix the rarely happened unit test exception of generic algorithm

["Shaofeng SHI (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/KYLIN-3306?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Shaofeng SHI resolved KYLIN-3306.
---------------------------------
    Resolution: Fixed

> Fix the rarely happened unit test exception of generic algorithm
> ----------------------------------------------------------------
>
>                 Key: KYLIN-3306
>                 URL: https://issues.apache.org/jira/browse/KYLIN-3306
>             Project: Kylin
>          Issue Type: Bug
>            Reporter: Zhong Yanghong
>            Assignee: Zhong Yanghong
>            Priority: Major
>             Fix For: v2.3.1
>
>         Attachments: APACHE-KYLIN-3306.patch
>
>
> There's a bug in the following code:
> {code}
> private Chromosome rouletteWheel(final List<Chromosome> chromosomes, final double totalFitness) {
>         float rnd = (float) (GeneticAlgorithm.getRandomGenerator().nextDouble() * totalFitness);
>         float runningScore = 0;
>         for (Chromosome o : chromosomes) {
>             if (rnd >= runningScore && rnd <= runningScore + o.getFitness()) {
>                 return o;
>             }
>             runningScore += o.getFitness();
>         }
>         return null;
>     }
> {code}
> We should use double instead of float.
> For example, (float) (0.9999999988948809 * 40.510999999999996) = 40.511 > 40.510999999999996



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