zoukankan      html  css  js  c++  java
  • Biased Random Number Generator

    I am looking for a random number generator that is biased towards giving numbers "furthest away" from a set of already selected numbers. 
    For example, if my range is [1, 50] and I pass in a set of numbers such as (1, 20, 40),
    then I would want the generator to "prefer" producing numbers further away from 1, 20, and 40.
    Therefore, numbers such as 50 or 30 would be more likely to be drawn than 20 or 40.
    I suspect that this may already exist. Does anyone know of such an implementation that I can use for Java?

    Here is a way you can do it by hand. Basically the idea is we take in some numbers we don't want to generate, then we generate a random number and if that number is in the list of numbers we don't want we try again up to a maximum number of retries.

    public static void main(String[] args) {
    
            int times = 25;
            int[] listOfNumbers = {1, 2, 3};
            int max = 5, min = 1;
    
            while(times-- > 0)
            {   
                System.out.print(GeneratePreferredNumbers(listOfNumbers, max, min) + " ");
            }
    
    
        }//main method
    
        public static Integer GeneratePreferredNumbers(int[] listOfNotPreffered, int max, int min)
        {
            Random rand = new Random();
            int randomNum;
            int retry = 1; //increasing this lessons the likely of our non-preferred numbers to show up
            HashSet<Integer> notPrefer = new HashSet<>();
    
            //add all the numbers we don't want to generate into a HashSet for easy lookup
            for(int index = 0; index < listOfNotPreffered.length; index++)
                notPrefer.add(listOfNotPreffered[index]);
    
            do {
                randomNum = rand.nextInt((max - min) + 1) + min;
                if(notPrefer.contains(randomNum))
                {
                    retry--;
                }
                //we found a good value, let's return it
                else{
                    retry = 0;
                }
            } while (retry > 0);
    
            return randomNum;
        }
    

      NOTE: The more times we allow the algorithm to retry the more likely our output will consist of numbers we want. This allows you to control how likely you want those non-preferred numbers to show up. This makes sense because if we were to increase the retry to infinite, this would stop only when the number generated is not contained in our list non-preferred numbers.

  • 相关阅读:
    vaddin使用技巧
    数据库连接&数据库进程&数据库操作
    gcc编译器参数使用及解决
    smtp服务器搭建(实现本地通讯)
    jdk+tomcat+mysql搭建网站无法打开
    ie8此加载项无法恢复&网站还原错误问题解决=lr成功打开ie成功录制脚
    loadrunner打不开ie&ie默认浏览器设置方法
    判断iis是否已经安装
    loadrunner常见问题
    代码中字符串比较长时可以分行写
  • 原文地址:https://www.cnblogs.com/apanda009/p/7953008.html
Copyright © 2011-2022 走看看