#encoding:utf-8
#==============================================================================
# ■ Rand Formulas
#------------------------------------------------------------------------------
# Provides additional random methods, mainly for battle formulas
#==============================================================================
# ● Rd.gauss(mean : Number, stddev : Number)
# 生成高斯分布的一个随机数（貌似是正态分布或者类似），第一个参数是平均值，第二个参数是方差
# Generates a random gaussian distributed number.
# Eg. Rd.gauss(1,0.1)
#==============================================================================
# ● Rd.percentage
# 返回一个1~100的数值
# Returns a value between 1 and 100
#==============================================================================
# ● Rd.between(min : Number, max : Number)
# 平均分布的随机数，位于min与max之间。
# Generates a equally distributed random number between min and max.
#==============================================================================
# ● Rd.betweenP(min : Number, max : Number)
# 平均分布的随机数，位于min/100与max/100之间
# Generates a equally distributed random number between min/100 and max/100
#==============================================================================
=begin
This is free and unencumbered software released into the public domain.
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In jurisdictions that recognize copyright laws, the author or authors
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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For more information, please refer to <[url]http://unlicense.org/[/url]>
=end
class RandomGaussian
def initialize(mean, stddev, rand_helper = lambda { Kernel.rand })
@rand_helper = rand_helper
@mean = mean
@stddev = stddev
@valid = false
@next = 0
end
def rand
if @valid then
@valid = false
return @next
else
@valid = true
x, y = self.class.gaussian(@mean, @stddev, @rand_helper)
@next = y
return x
end
end
private
def self.gaussian(mean, stddev, rand)
theta = 2 * Math::PI * rand.call
rho = Math.sqrt(-2 * Math.log(1 - rand.call))
scale = stddev * rho
x = mean + scale * Math.cos(theta)
y = mean + scale * Math.sin(theta)
return x, y
end
end
#[url]http://stackoverflow.com/questions/5825680/code-to-generate-gaussian-normally-distributed-random-numbers-in-ruby[/url]
module Rd
class << self
# Number -> Number -> Number
def gauss mean, stddev
g = RandomGaussian.new(mean, stddev)
return g.rand
end
# Unit -> Number
def percentage
return Random.new.rand(1..100)
end
# Number -> Number -> Number
def between a, b
return Random.new.rand(a..b)
end
# Number -> Number -> Number
def betweenP a, b
return between(a,b) / 100.0
end
end
end