comparison toolboxes/FullBNT-1.0.7/bnt/examples/limids/oil1.m @ 0:e9a9cd732c1e tip

first hg version after svn

+% oil wildcatter influence diagram in Cowell et al p172
+
+% T = test for oil?
+% UT = utility (negative cost) of testing
+% O = amount of oil = Dry, Wet or Soaking
+% R = results of test = NoStrucure, OpenStructure, ClosedStructure or NoResult
+% D = drill?
+% UD = utility of drilling
+
+% Decision sequence = T R D O
+
+T = 1; UT = 2; O = 3; R = 4; D = 5; UD = 6;
+N = 6;
+dag = zeros(N);
+dag(T, [UT R D]) = 1;
+dag(O, [R UD]) = 1;
+dag(R, D) = 1;
+dag(D, UD) = 1;
+
+ns = zeros(1,N);
+ns(O) = 3; ns(R) = 4; ns(T) = 2; ns(D) = 2; ns(UT) = 1; ns(UD) = 1;
+
+limid = mk_limid(dag, ns, 'chance', [O R], 'decision', [T D], 'utility', [UT UD]);
+
+limid.CPD{O} = tabular_CPD(limid, O, [0.5 0.3 0.2]);
+tbl = [0.6 0 0.3 0 0.1 0  0.3 0 0.4 0 0.4 0  0.1 0 0.3 0 0.5 0  0 1 0 1 0 1];
+limid.CPD{R} = tabular_CPD(limid, R, tbl);
+
+limid.CPD{UT} = tabular_utility_node(limid, UT,  [-10 0]);
+limid.CPD{UD} = tabular_utility_node(limid, UD, [-70 50 200  0 0 0]);
+
+if 1
+  % start with uniform policies
+  limid.CPD{T} = tabular_decision_node(limid, T);
+  limid.CPD{D} = tabular_decision_node(limid, D);
+else
+  % hard code optimal policies
+  limid.CPD{T} = tabular_decision_node(limid, T, [1.0 0.0]);        
+  a = 0.5; b = 1-a; % arbitrary value
+  tbl = myreshape([0 a 1 a 1 a a a  1 b 0 b 0 b b b], ns([T R D]));
+  limid.CPD{D} = tabular_decision_node(limid, D,  tbl);
+end
+
+%fname = '/home/cs/murphyk/matlab/Misc/loopybel.txt';
+
+engines = {};
+engines{end+1} = global_joint_inf_engine(limid);
+engines{end+1} = jtree_limid_inf_engine(limid);
+%engines{end+1} = belprop_inf_engine(limid, 'max_iter', 3*N, 'filename', fname);
+
+exact = [1 2];
+%approx = 3;
+approx = [];
+
+E = length(engines);
+strategy = cell(1, E);
+MEU = zeros(1, E);
+for e=1:E
+  [strategy{e}, MEU(e)] = solve_limid(engines{e});
+  MEU
+end
+MEU
+
+for e=exact(:)'
+  assert(approxeq(MEU(e), 22.5))
+  % U(T=yes)  U(T=no)
+  % 1         0
+  assert(argmax(strategy{e}{T}) == 1); % test = yes
+  t = 1; % test = yes
+  % strategy{D} T       R      U(D=yes=1)  U(D=no=2)
+  %             1=yes   1=noS  0           1         Don't drill
+  %             2=no    1=noS  1           0
+  %             1=yes   2=opS  1           0
+  %             2=no    2=opS  1           0
+  %             1=yes   3=clS  1           0
+  %             2=no    3=clS  1           0
+  %             1=yes   4=unk  1           0
+  %             2=no    4=unk  1           0
+  
+  for r=[2 3] % OpS, ClS
+    assert(argmax(squeeze(strategy{e}{D}(t,r,:))) == 1); % drill = yes
+  end
+  r = 1; % noS
+  assert(argmax(squeeze(strategy{e}{D}(t,r,:))) == 2); % drill = no
+end
+
+
+for e=approx(:)'
+  approxeq(strategy{exact(1)}{T}, strategy{e}{T})
+  approxeq(strategy{exact(1)}{D}, strategy{e}{D})
+end