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matlabbayesian-networks
lxgeek
lxgeek

Reputation: 1814

Bayes Net Toolbox for MATLAB

I'm new to learning the Bayes Net Toolbox for MATLAB, and I have tried this:

N = 4;
dag = zeros( N, N );
C = 1; S = 2; R = 3; W = 4;
dag( C, [R S] ) = 1;
dag( R, W ) = 1;
dag( S, W ) = 1;

discrete_nodes = 1:N;
node_sizes = [ 4 2 3 5];

onodes = [];
bNet = mk_bnet( dag, node_sizes, 'discrete', discrete_nodes, 'observed', onodes  );

bNet.CPD{C} = tabular_CPD( bNet, C, 'CPT', [0.5 0.5] );
bNet.CPD{R} = tabular_CPD( bNet, R, 'CPT', [0.8 0.2 0.2 0.8 ] );
bNet.CPD{S} = tabular_CPD( bNet, S, 'CPT', [0.5 0.9 0.5 0.1] );
bNet.CPD{W} = tabular_CPD( bNet, W, 'CPT', [1 0.1 0.1 0.01 0 0.9 0.9 0.99 ] );

engine = jtree_inf_engine( bNet);

evidence = cell( 1,N );
evidence{W} = 2;

[engine, loglik] = enter_evidence( engine, evidence );

marg = marginal_nodes( engine, S );
marg.T
p = marg.T(2)

But it doesn't work, and it prints:

??? Error using ==> reshape

To reshape, the number of elements must not change.

Error in ==> myreshape at 10
  T = reshape(T, sizes(:)');

Error in ==> tabular_CPD.tabular_CPD at 90
      CPD.CPT = myreshape(T, fam_sz);

Error in ==> bnet at 19
bNet.CPD{R} = tabular_CPD( bNet, R, 'CPT', [0.8 0.2 0.2 0.8 ] );

Upvotes: 2

Views: 1776

Answers (1)

lxgeek
lxgeek

Reputation: 1814

I had a mistake in:

node_sizes = [ 4 2 3 5];

It should have been:

node_sizes = 2*ones(1,N);

Upvotes: 1

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