/* 

  CSI (Context-specific independence) in Picat.

  From BLOG example/csi:
  """
  Model that illustrates context-specific independence.  This is a 
  parameterization of the model shown in Fig. 3 of (Milch et al., 
  AISTATS 2005): X depends on W when U is true, but on V when U is false.  
  
  The probability of X being true given no evidence is P(X=true) = 0.596.
  """

  Cf my Gamble model gamble_csi.rkt

  This program was created by Hakan Kjellerstrand, hakank@gmail.com
  See also my Picat page: http://www.hakank.org/picat/

*/

import ppl_distributions, ppl_utils.
import util.

main => go.

/*

  var : x
  Probabilities:
  true: 0.5988000000000000
  false: 0.4012000000000000
  mean = [true = 0.5988,false = 0.4012]

*/
go ?=>
  reset_store,
  run_model(10_000,$model,[show_probs_trunc,mean]),
  nl,
  % show_store_lengths,
  % fail,
  nl.
go => true.
  
  
model() =>
  U = flip(0.3),
  V = flip(0.9),
  W = flip(0.1),

  X = condt(U,
            condt(W,flip(0.8),flip(0.2)),
            condt(V,flip(0.8),flip(0.2))),
   
  add("x",X).