#26 Factor builders for Hfactor

src/main/java/ch/idsia/credici/factor/HalfSpaceFactorBuilder.java

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+package ch.idsia.credici.factor;
+
+import ch.idsia.crema.IO;
+import ch.idsia.crema.core.Strides;
+import ch.idsia.crema.factor.credal.linear.separate.SeparateHalfspaceFactor;
+import ch.idsia.crema.factor.credal.linear.separate.SeparateHalfspaceFactorFactory;
+import ch.idsia.crema.model.graphical.DAGModel;
+import com.google.common.primitives.Ints;
+import org.apache.commons.math3.optim.linear.LinearConstraint;
+import org.apache.commons.math3.optim.linear.Relationship;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+
+public class HalfSpaceFactorBuilder {
+
+
+	public static LinearConstraint[] buildConstraints(boolean normalized, boolean nonnegative, double[][] coefficients, double[] values, Relationship... rel) {
+
+		int left_combinations = coefficients[0].length;
+		List<LinearConstraint> C = new ArrayList<LinearConstraint>();
+
+
+		// check the coefficient shape
+		for (double[] c : coefficients) {
+			if (c.length != left_combinations)
+				throw new IllegalArgumentException("ERROR: coefficient matrix shape");
+		}
+
+		// check the relationship vector length
+		if (rel.length == 0) rel = new Relationship[]{Relationship.EQ};
+		if (rel.length == 1) {
+			Relationship[] rel_aux = new Relationship[coefficients.length];
+			for (int i = 0; i < coefficients.length; i++)
+				rel_aux[i] = rel[0];
+			rel = rel_aux;
+		} else if (rel.length != coefficients.length) {
+			throw new IllegalArgumentException("ERROR: wrong relationship vector length: " + rel.length);
+		}
+
+		for (int i = 0; i < coefficients.length; i++) {
+			C.add(new LinearConstraint(coefficients[i], rel[i], values[i]));
+		}
+
+
+		// normalization constraint
+		if (normalized) {
+			double[] ones = new double[left_combinations];
+			for (int i = 0; i < ones.length; i++)
+				ones[i] = 1.;
+			C.add(new LinearConstraint(ones, Relationship.EQ, 1.0));
+		}
+
+		// non-negative constraints
+		if (nonnegative) {
+			double[] zeros = new double[left_combinations];
+			for (int i = 0; i < left_combinations; i++) {
+				double[] c = zeros.clone();
+				c[i] = 1.;
+				C.add(new LinearConstraint(c, Relationship.GEQ, 0));
+
+			}
+		}
+
+		return C.toArray(LinearConstraint[]::new);
+	}
+
+
+	public static SeparateHalfspaceFactor deterministic(Strides left, Strides right, int... assignments) {
+
+		if (assignments.length != right.getCombinations())
+			throw new IllegalArgumentException("ERROR: length of assignments should be equal to the number of combinations of the parents");
+
+		if (Ints.min(assignments) < 0 || Ints.max(assignments) >= left.getCombinations())
+			throw new IllegalArgumentException("ERROR: assignments of deterministic function should be in the inteval [0," + left.getCombinations() + ")");
+
+
+		SeparateHalfspaceFactorFactory factory =
+				SeparateHalfspaceFactorFactory.factory().domain(left, right);
+
+
+		int left_combinations = left.getCombinations();
+
+		for (int i = 0; i < right.getCombinations(); i++) {
+			double[][] coeff = new double[left_combinations][left_combinations];
+			for (int j = 0; j < left_combinations; j++) {
+				coeff[j][j] = 1.;
+			}
+			double[] values = new double[left_combinations];
+			values[assignments[i]] = 1.;
+
+			// Build the constraints
+			LinearConstraint[] C = buildConstraints(true, true, coeff, values, Relationship.EQ);
+
+			// Add the constraints
+			for (LinearConstraint c : C) {
+				factory.constraint(c, i);
+			}
+		}
+
+		return factory.get();
+	}
+
+	public static void main(String[] args) throws IOException {
+
+		Path folder = Path.of(".");
+
+		folder.resolve("models/party.uai");
+
+
+		DAGModel m = IO.read(folder.resolve("models/party.uai").toString());
+
+		SeparateHalfspaceFactor f = deterministic(m.getDomain(3), m.getDomain(2,1), 0,0,1,1);
+		System.out.println(f);
+
+
+
+	}
+
+}