random | 易学教程

Scaling Int uniform random range into Double one

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问题 Actually, I have several interweaving questions. (If it matters I use C#.) First. I have a prng that generates random numbers in UInt32 range, from 0 to UInt32.Max inclusive. I want to preserve the uniformity as much as possible. What is the main idea to get [a,b], (a,b) double ranges (such as [0,1], [0,1), (0,1), [-2,4], (-10,10))? I'm concerned about the following. I have 4 294 967 296 prng outcomes. It is less than numbers in [0,1] double range — 2^53. So I construct 4 294 967 296-ary

属性动画补间动画帧动画基本使用案例 MD

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Markdown版本笔记我的GitHub首页我的博客我的微信我的邮箱 MyAndroidBlogs baiqiantao baiqiantao bqt20094 baiqiantao@sina.com 目录目录属性动画属性动画基本使用演示 MainActivity View包装类构建动画的工具类自定义 TypeEvaluator 实现抛物线动画效果使用 LayoutTransition 为布局容器中子View的显示与消失设置过渡动画使用 LayoutAnimationController 为布局容器中的控件播放同样的动画几十种 Interpolator 演示 SecondActivity InterpolatorActivityInterpolatorActivity 补间动画补间动画基本使用演示 MainActivity AnimHelper 几十种 Interpolator 演示自定义 Activity 转场动画系统定义的几个补间动画常用的窗口显示、消失动画帧动画基本使用案例帧动画简介 AnimationDrawable 类简介补充清单文件中注册Activity 属性动画属性动画基本使用演示 MainActivity // 可操控的属性有：alpha；x/y；scaleX/scaleY；rotation/rotationX

Generating Uniform Random Deviates within a given range

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问题 I'd like to generate uniformly distributed random integers over a given range. The interpreted language I'm using has a builtin fast random number generator that returns a floating point number in the range 0 (inclusive) to 1 (inclusive). Unfortunately this means that I can't use the standard solution seen in another SO question (when the RNG returns numbers between 0 (inclusive) to 1 (exclusive) ) for generating uniformly distributed random integers in a given range: result=Int((highest -

Random hex colour

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问题 I am using the following code to generate a random hex colour on certain elements on my page. CSS /**** Random hex values ****/ .isotope-brick.color0 .brick-overlay { background-color: #E1A2AC; } .isotope-brick.color0 .brick-info { color: #E1A2AC; } .isotope-brick.color1 .brick-overlay { background-color: #FDC300; } .isotope-brick.color1 .brick-info { color: #FDC300; } .isotope-brick.color2 .brick-overlay { background-color: #56AF31; } .isotope-brick.color2 .brick-info { color: #56AF31; }

Sometimes my set comes out ordered and sometimes not (Python)

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问题 So I know that a set is supposed to be an unordered list. I am trying to do some coding of my own and ended up with a weird happening. My set will sometimes go in order from 1 - 100 (when using a larger number) and when I use a smaller number it will stay unordered. Why is that? #Steps: #1) Take a number value for total random numbers in 1-100 #2) Put those numbers into a set (which will remove duplicates) #3) Print that set and the total number of random numbers import random randomnums = 0

Having problems keeping a simulation deterministic with random.Random(0) in python

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问题 I have a very large simulation in python with lots of modules. I call a lot of random functions. To keep the same random results I have a variable keep_seed_random. As so: import random keep_seed_random = True if keep_seed_random is False: fixed_seed = random.Random(0) else: fixed_seed = random Then I use fixed_seed all over the program, such as fixed_seed.choice(['male', 'female']) fixed_seed.randint() fixed_seed.gammavariate(3, 3) fixed_seed.random() fixed_seed.randrange(20, 40) and so on..

SQL Random number not working

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问题 declare @fieldForceCounter as int declare @SaleDate as dateTime declare @RandomNoSeed as decimal set @fieldForceCounter = 1 set @SaleDate = '1 Jan 2009' set @RandomNoSeed = 0.0 WHILE @fieldForceCounter <= 3 BEGIN while @SaleDate <= '1 Dec 2009' begin INSERT INTO MonthlySales(FFCode, SaleDate, SaleValue) VALUES(@fieldForceCounter, @SaleDate, RAND(@RandomNoSeed)) set @saleDate = @saleDate + 1 set @RandomNoSeed = Rand(@RandomNoSeed) + 1 end set @SaleDate = '1 Jan 2009' set @fieldForceCounter =

Choose unique random number from an array

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问题 b is the maximum winner that I want. b.times do winner = participant[rand(participant.count)] end I need to generate a unique winner every time. How can I achieve this without making too many changes to this code? 回答1: There is already a method for that. Just use Array#sample: winners = participants.sample(b) 回答2: You can use Array#delete_at which deletes an item at specified index and returns the deleted item. We can now ensure that item once picked as winner will never be picked again #

Generate N quasi random numbers in less than O(N)

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问题 This was inspired by a question at a job interview: how do you efficiently generate N unique random numbers? Their security and distribution/bias don't matter. I proposed a naive way of calling rand() N times and eliminating dupes by trial and error, thus getting inefficient and flawed solution. Then I've read this SO question, these algorithms are great for getting quality unique numbers and they are O(N). But I suspect there are ways to get low-quality unique random numbers for dummy tasks

Generate N quasi random numbers in less than O(N)

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