From: Guillaume Marcais <guslist@...>
Date: 2004-02-11T09:08:52+09:00
Subject: Re: eistein's riddle

I ran it and it crashed on me after 4 days of hard computation (on a
double PII 400Mhz)!

But I love the method though.

Guillaume.

% time ruby amb-test2.rb
amb-test2.rb:45: undefined local variable or method `houses' for
main:Object (NameError)
Command exited with non-zero status 1
352198.51user 252.87system 98:25:05elapsed 2%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (273major+54916minor)pagefaults 0swaps

On Sun, 2004-02-08 at 20:17, Avi Bryant wrote:
> Hardly efficient (in fact I haven't yet run it through to completion),
> but since we were recently talking about amb:
> ---
> $colors = ["red", "white", "yellow", "blue", "green"]
> $nationalities = ["Brit", "Swede", "Dane", "Norwegian", "German"]
> $beverages = ["tea", "coffee", "milk", "beer", "water"]
> $cigars = ["Pall Mall", "Blends", "Dunhill", "Prince", "Bluemasters"]
> $pets = ["dogs", "birds", "cats", "horse", "fish"]
> 
> class House
>   attr_reader :color, :nationality, :beverage, :cigar, :pet
> 
>   def initialize
>     @color = $amb.one_of($colors)
>     @nationality = $amb.one_of($nationalities)
>     @beverage = $amb.one_of($beverages)
>     @cigar = $amb.one_of($cigars)
>     @pet = $amb.one_of($pets)
>   end
> end
> 
> def find(property, value)
>   $houses.detect{|h| h.send(property) == value} || $amb.fail
> end
> 
> def color(s) find(:color, s) end
> def nationality(s) find(:nationality, s) end
> def beverage(s) find(:beverage, s) end
> def cigar(s) find(:cigar, s) end
> def pet(s) find(:pet, s) end
> 
> def next_door(h1, h2)
>   ($houses.index(h1) - $houses.index(h2)).abs == 1
> end
> 
> $amb = Amb.new
> $houses = (1..5).collect{House.new}
> 
> #fact 1
> $amb.assert(nationality("Brit").color == "red")
> #fact 2
> $amb.assert(nationality("Swede").pet == "dogs")
> #fact 3
> $amb.assert(nationality("Dane").beverage == "tea")
> #fact 4
> $amb.assert(houses.index(color("white")) -
> houses.index(color("green")) == 1)
> #fact 5
> $amb.assert(color("green").beverage == "coffee")
> #fact 6
> $amb.assert(cigar("Pall Mall").pet == "birds")
> #fact 7
> $amb.assert(color("yellow").cigar == "Dunhill")
> #fact 8
> $amb.assert(houses[2].beverage == "milk")
> #fact 9
> $amb.assert(houses[0].nationality == "Norwegian")
> #fact 10
> $amb.assert(next_door(cigar("Blends"), pet("cats")))
> #fact 11
> $amb.assert(next_door(cigar("Dunhill"), pet("horse")))
> #fact 12
> $amb.assert(cigar("Bluemasters").beverage == "beer")
> #fact 13
> $amb.assert(nationality("German").cigar == "Prince")
> #fact 14
> $amb.assert(next_door(nationality("Norwegian"), color("blue")))
> #fact 15
> $amb.assert(next_door(cigar("Blends"), beverage("water")))
> 
> #No owners have the same pet, smoke the same brand of cigar
> #or drink the same beverage.
> $amb.assert(houses.collect{|h| h.color}.uniq.size == 5)
> $amb.assert(houses.collect{|h| h.nationality}.uniq.size == 5)
> $amb.assert(houses.collect{|h| h.beverage}.uniq.size == 5)
> $amb.assert(houses.collect{|h| h.cigar}.uniq.size == 5)
> $amb.assert(houses.collect{|h| h.pet}.uniq.size == 5)
> 
> puts "The " + pet("fish").nationality + " owns the fish"
>