From: "Thomas A. Reilly" <w3gat@...>
Date: 2002-03-22T12:26:01+09:00
Subject: Re: ruby simulations

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When I had learned of ruby I had thought that it would be useful to create 
a quick and dirty simulation.  Living in Louisiana we have small towns 
almost everyone who has the same last name and I have also wondered about 
the growth of communities such as the Mayflower community and the lost 
colony in Virginia.

It was a great way to learn ruby.

Tom Reilly
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Content-Disposition: attachment; filename="FAMNAM.RB"

#----------------------------------------------------------------
#
#	famnam.rb - family name simulation
#
#----------------------------------------------------------------

$mar_rate = .11
$birth_rate = .21
$divorce_rate = .013
$pstart = 200		# of people at the start of simulation
$simyrs = 1000         # years of simulation


def lookup(arg,argt,argf)
	i = 0
	if argt.size == argf.size
		argt.each_index do |i|
			if argt[i] >= arg
				break
			end
		end
		if argt[i + 1] == argt[i]
			argf[i]
		else
			delta = (argf[i + 1] - argf[i])/(argt[i + 1] - argt[i])
			dd = (arg - argt[i]) / (argt[i + 1] - argt[i])
			argf[i] + (dd * delta)
		end
	else
		print "ARRAY SIZE ERROR ", argt.size, " ", argf.size, "\n"
		exit
	end
end

#----------------------------------------------------------------------
class Birth
	def initialize(father, mother)
		@sex = rand(2)
		if @sex == 1
			@dom = $yr + lookup(rand() * 100,$ixm,$ixa)
		else
			@dom = $yr + lookup(rand() * 100,$ixf,$ixa)
		end
		@dob = $yr
		@pid = getgene
		@name = ""
		@married = false
		@gene = Array.new
		if father == nil
			@gene[0] = getgene
			@gene[1] = getgene
			@gene[2] = getgene
			mkname
		else
			@name = father.name
			@gene[0] = father.pid
			@gene[1] = father.gene[0]
			@gene[2] = father.gene[1]
		end
		if mother == nil
			@gene[3] = getgene
			@gene[4] = getgene 
			@gene[5] = getgene 
		else
			@gene[3] = mother.pid
			@gene[4] = mother.gene[0]
			@gene[5] = mother.gene[1]
			mkname if father == nil
		end
	end	

	def view
		print "name ", @name, " pid ", @pid, " dob ", @dob, " mort ", @dom, " sex ", @sex, "\n"
		print "   parents "
		print gene.each {|i| print i, " "}		
		print "---\n"
	end

	def name
		@name
	end

	def pid
		@pid
	end

	def gene
		@gene
	end

	def dom
		@dom
	end

	def rip
		$yr > @dom
	end

	def married
		@married
	end

	def marry
		@married = true
	end

	def unmarry
		@married = false
	end

	def age
		$yr - @dob
	end

	def sex
		@sex
	end

	def dob
		@dob
	end

private
	def mkname
		@name = ""
		(1..5).each do |i|
			ch = rand(25)
			ch += "A".slice(0)
			@name = @name + ch.chr
		end
	end

	def getgene
		$pix += 1
	end
			
end

#--------------------------------------------------------------------------
public
class Population
	def initialize
		@plist = Array.new
		@marriages = Array.new
		@male_eligible = Array.new 
		@female_eligible = Array.new
		@birth_count = 0
		@marriage_count = 0
		@died = 0
		@name_count = 0
		$pstart.times do
			@plist.push(Birth.new(nil,nil))
		end
	end

	def birth(dad,mom)
		@plist.push(Birth.new(dad,mom))
	end

	def size
		@plist.size
	end

	def kill
		@died = 0
#|		@plist.each_index do |person|
#|			print @plist[person].dom, " ", @plist[person].dom.type, "\n"
#|		end
		@plist.each {|per| @died += 1 if per.rip}
		@plist.delete_if {|per| per.rip}
		@plist.compact
		@died
	end 

	def each
		for i in @plist
			yield(i)
		end
	end

		# - Count the number of names in the population
	def names
		names = Hash.new(0)
		@plist.each {|p| names[p.name] += 1}
		@name_count = names.size
	end


	def stats
		print "YEAR ", $yr, ", POPULATION ", @plist.size, ", MARRIAGES ", @marriage_count, ", BIRTHS ", @birth_count, ", DEATHS ", @died, ", NAMES ", @name_count, "\n" 
		exit if @plist.size == 0
	end		

	def marriage_end
		@marriages.each_index do |m|
			msw = false
			if $yr > @marriages[m].him.dom || $yr > @marriages[m].her.dom
				@marriages[m].unmarry
				@marriages[m].smend
			else
				if rand() < $divorce_rate
					@marriages[m].unmarry
					@marriages[m].smend
				end
			end
		end
		@marriages.delete_if {|mp| mp.mend == true}
		@marriages.compact
	end

	def year
		marry
		make_babies
		names
		marriage_end
		kill
		stats
		wstat
	end

	def make_babies
		@birth_count = 0
		@marriages.each do |m|
			if $yr - m.her.dob > 15 && $yr - m.her.dob < 45
				if rand() < $birth_rate
					@birth_count += 1
					@plist.push(Birth.new(m.him,m.her))
				end
			end
		end		 
		
	end 

	def marry
		@male_eligible.clear
		@female_eligible.clear
		@marriage_count = 0
		@plist.each do |p|
			if p.sex == 1 && p.age > 16 && p.married == false then @male_eligible.push(p)
			end
			if p.sex == 0 && p.age > 16 && p.married == false then @female_eligible.push(p)
			end
		end
		melig = @male_eligible.size
		felig = @female_eligible.size
		if melig < felig
			marmin = melig
		else
			marmin = felig
				marmin = felig
		end
		(1..marmin).each do |i|
			marsw = false
			malep = rand(melig)
			femp = rand(felig)
			man_elig = @male_eligible[malep]
			lady_elig = @female_eligible[femp]
			# insest prevention
			lady_elig.gene.each do |fi|
				man_elig.gene.each do |mi|
					if fi == mi
						marsw = true
					end
				end
			end
			marsw = true if rand() > $mar_rate
			if marsw == false
				@marriages.push(Marriage.new(@male_eligible[ malep ], @female_eligible[ femp]))
				@marriage_count += 1
#				@male_eligible[malep].delete
#				@female_eligible[femp].delete
				melig -= 1
				felig -= 1
			end
		end
	end
	
	def pop_dist
		pop_a = Array.new(15,0)
		pop_tot = 0
		@plist.each {|p| pop_a[(p.age / 10).to_i] += 1}
		pop_a.each {|i| pop_tot += i}
		pop_a.each_index do |i|
			pf = 1000.0 * pop_a[i].to_f / pop_tot.to_f
			printf("%d  %0.2d\n",i,pf)
		end
	end

	def wstat
		$stfile.write("#{$yr}\t#{size}\t#{@marriages.size}\t#{@male_eligible.size}\t#{@female_eligible.size}\t#{@birth_count}\t#{@marriage_count}\t#{@died}\t#{@name_count}\n")
	end

end			

#----------------------------------------------------------------------
class Marriage
	def initialize(him,her)
		@mend_flag = false
		@him = him
		@her = her
		@him.marry
		@her.marry
	end

	def unmarry
		@him.unmarry
		@her.unmarry
	end

	def her
		@her
	end

	def him
		@him
	end

	def mend
		@mend
	end

	def smend
		@mend = true
	end

end

#----------------------------------------------------------------------
$yr = 1
$pix = 0
$ixa = [1,2,3,4,5,10,20,30,40,50,60,70,80,90,100,110,120,120]
$ixm = [0,1.33,2,2,2.67,3.33,4,4.67,5.33,14,24,47.33,77.33,96,99.33,100,100,100]
$ixf = [0,1.33,2,2,2,2,2.67,2.67,4,8,5.33,22,50,88.67,98,99.33,100,100]
$stfile = File.open("stfile","w")
$stfile.write("year\tsize\tmarriages\tmale_eligible\tfemale_eligible\tbirth_count\tmarriage_count\tdied\tname_count\n")

population = Population.new


 (1..$simyrs).each do 
	population.year
	$yr += 1
end
population.pop_dist
names = Hash.new(0)
population.each {|p| names[p.name] += 1}
names.each {|n,c| $stfile.write "#{n}\t#{c}\n"}
$stfile.close

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