private double multiLL(DoubleMatrix2D coeffs, Node dep, List<Node> indep) {
DoubleMatrix2D indepData =
factory2D.make(internalData.subsetColumns(indep).getDoubleData().toArray());
List<Node> depList = new ArrayList<>();
depList.add(dep);
DoubleMatrix2D depData =
factory2D.make(internalData.subsetColumns(depList).getDoubleData().toArray());
int N = indepData.rows();
DoubleMatrix2D probs =
Algebra.DEFAULT.mult(factory2D.appendColumns(factory2D.make(N, 1, 1.0), indepData), coeffs);
probs =
factory2D
.appendColumns(factory2D.make(indepData.rows(), 1, 1.0), probs)
.assign(Functions.exp);
double ll = 0;
for (int i = 0; i < N; i++) {
DoubleMatrix1D curRow = probs.viewRow(i);
curRow.assign(Functions.div(curRow.zSum()));
ll += Math.log(curRow.get((int) depData.get(i, 0)));
}
return ll;
}
/**
* Constructs a new on-the-fly BayesIM that will calculate conditional probabilities on the fly
* from the given discrete data set, for the given Bayes PM.
*
* @param bayesPm the given Bayes PM, which specifies a directed acyclic graph for a Bayes net and
* parametrization for the Bayes net, but not actual values for the parameters.
* @param dataSet the discrete data set from which conditional probabilities should be estimated
* on the fly.
*/
public OnTheFlyMarginalCalculator(BayesPm bayesPm, DataSet dataSet)
throws IllegalArgumentException {
if (bayesPm == null) {
throw new NullPointerException();
}
if (dataSet == null) {
throw new NullPointerException();
}
// Make sure all of the variables in the PM are in the data set;
// otherwise, estimation is impossible.
BayesUtils.ensureVarsInData(bayesPm.getVariables(), dataSet);
// DataUtils.ensureVariablesExist(bayesPm, dataSet);
this.bayesPm = new BayesPm(bayesPm);
// Get the nodes from the BayesPm. This fixes the order of the nodes
// in the BayesIm, independently of any change to the BayesPm.
// (This order must be maintained.)
Graph graph = bayesPm.getDag();
this.nodes = graph.getNodes().toArray(new Node[0]);
// Initialize.
initialize();
// Create a subset of the data set with the variables of the IM, in
// the order of the IM.
List<Node> variables = getVariables();
this.dataSet = dataSet.subsetColumns(variables);
// Create a tautologous proposition for evidence.
this.evidence = new Evidence(Proposition.tautology(this));
}
