construct185.rb

def f2(n)
	return n.odd? ? (n * 3 + 1) / 2 : n / 2

end

def adj(x, m, n, s2, p2, p, x3)
	s2.replace(p[0...x] + (x3 % 2).to_s)
	m = (s2[x, 1] == p[x, 1])
	n = p2.reverse.to_i(2)
	p2[x, 1] = m ? '11' : '01'
	return m, n, x3
end

def terras121(p)
	
	p2 = ['01', '11'][p[0, 1].to_i]
	n = 1
	n3 = 0
	m = p2 == '11'
	x3 = (p2.reverse.to_i(2)) >> 1

	(1...p.length).each \
	{
		|x|

		if (!m)
			ns = n.to_s(2)
			ns[0, 1] = ''
			m1 = x3 - 3**n3
			n1 = f2(m1)
		end

		n3 = p[0...x].split('').select { |z| z == '1' }.size
		
		s2 = ''
		m, n, x3 = adj(x, m, n, s2, p2, p, m ? (f2(x3) + 3**n3) : (n1 + 3**n3))
	}

	n = p2.reverse.to_i(2)

	return n
end

def seq(n)
	l = [n]
	
	while (n != 1)
		n = f2(n)
		
		l << n
		
	end
	return l
end



def dense(w, d)
	w2 = w - 1
	
	a = (0...w2).to_a
	s = '0' * w2
	(1..(d * w - 1)).map { a.delete_at(rand(a.size)) }.each { |x| s[x, 1] = '1' }
	return ('1' + s)
	
end

def d(s)
        c = s.split('').select { |x| x == '1' }.size
	d = c.to_f / s.length
        return d
        
end

def outd(f, l)
	f.puts('$dat << eof')
	k = l[0].keys
	
	f.puts(k.join("\t"))
	l.each { |x| f.puts(x.values.join("\t")) }

	f.puts('eof')
	return k
end

def plot(n, l2)
	l = seq(n)
	l.each_with_index \
	{
		|x, j|
		l2 << {'j' => j, 'w' => x.to_s(2).length, 'x3' => x % 3}
	}
	l2 << {}
end


l2 = []
plot(dense(100, 0.5).to_i(2), l2)
plot(terras121(dense(75, 0.85)), l2)

outd(f = File.open('gnuplot.cmd', 'w'), l2)
cs = l2[0].keys.map { |x| "(column('#{x}'))" }.join(':')
f.puts("plot $dat using #{cs} with point linecolor variable ps 0.5 pt 5")
f.close