comparison toolboxes/FullBNT-1.0.7/bnt/CPDs/@root_CPD/root_CPD.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function CPD = root_CPD(bnet, self, val)
+% ROOT_CPD Make a conditional prob. distrib. which has no parameters.
+% CPD = ROOT_CPD(BNET, NODE_NUM, VAL)
+%
+% The node must not have any parents and is assumed to always be observed.
+% It is a way of modelling exogenous inputs to a model.
+% VAL is the value to which the root is clamped (default: [])
+
+
+if nargin==0
+  % This occurs if we are trying to load an object from a file.
+  CPD = init_fields;
+  CPD = class(CPD, 'root_CPD', generic_CPD(1));
+  return;
+elseif isa(bnet, 'root_CPD')
+  % This might occur if we are copying an object.
+  CPD = bnet;
+  return;
+end
+CPD = init_fields;
+
+
+if nargin < 3, val = []; end
+
+ns = bnet.node_sizes;
+ps = parents(bnet.dag, self);
+if ~isempty(ps)
+  error('root CPDs should have no parents')
+end
+
+CPD.self = self;
+CPD.val = val;
+CPD.sizes = ns(self);
+
+clamped = 1;
+CPD = class(CPD, 'root_CPD', generic_CPD(clamped));
+
+
+%%%%%%%%%%%
+
+function CPD = init_fields()
+% This ensures we define the fields in the same order 
+% no matter whether we load an object from a file,
+% or create it from scratch. (Matlab requires this.)
+
+CPD.self = [];
+CPD.val = [];
+CPD.sizes = [];