/** Babai's algorithm should work perfectly for Zn. This tests that it does. */
@Test
public void returnsCorrectForZn() {
System.out.println("returnsCorrectForZn");
int M = 10;
double[] y = {1.1, 2.2, 3.9, -4.1, -100.49};
// construct the integer lattice
Zn lattice = new Zn(y.length);
Mbest instance = new Mbest(lattice, M);
lattice.nearestPoint(y);
double[] xtrue = lattice.getLatticePoint();
double[] utrue = lattice.getIndex();
instance.nearestPoint(y);
double[] xtest = instance.getLatticePoint();
double[] utest = instance.getIndex();
System.out.println(VectorFunctions.print(xtrue));
System.out.println(VectorFunctions.print(xtest));
assertTrue(VectorFunctions.distance_between(utest, utrue) < 0.00001);
assertTrue(VectorFunctions.distance_between(xtest, xtrue) < 0.00001);
assertTrue(VectorFunctions.distance_between(utest, xtrue) < 0.00001);
assertTrue(VectorFunctions.distance_between(xtest, utrue) < 0.00001);
}
/** Test a column matrix. */
@Test
public void testSmallDeviations() {
System.out.println("testSmallDeviations");
// run nearest point test by making small deviations (del) to lattice points.
int iters = 10;
Random r = new Random();
double del = 0.0001;
for (int t = 0; t < iters; t++) {
int n = r.nextInt(100) + 5;
LatticeAndNearestPointAlgorithm lattice = new AnstarSorted(n - 1);
Matrix G = lattice.getGeneratorMatrix();
Mbest instance = new Mbest(lattice, n);
// System.out.println("G is " + G.getRowDimension() + " by " + G.getColumnDimension());
double[] x = new double[G.getRowDimension()];
double[] xdel = new double[G.getRowDimension()];
double[] u = VectorFunctions.randomIntegerVector(n, 1000);
// System.out.println("u is length " + u.length + ", x is length" + x.length);
VectorFunctions.matrixMultVector(G, u, x);
for (int i = 0; i < x.length; i++) {
xdel[i] = x[i] + r.nextGaussian() * del;
}
instance.nearestPoint(xdel);
double dist = VectorFunctions.distance_between(instance.getLatticePoint(), x);
System.out.println(dist);
assertEquals(true, dist < 0.00001);
}
}
/** Test a column matrix. */
@Test
public void testBeatsOrEqualsBabai() {
System.out.println("testBeatsOrEqualsBabai");
// run nearest point test by making small deviations (del) to lattice points.
int iters = 100;
Random r = new Random();
double del = 1000.0;
for (int t = 0; t < iters; t++) {
int n = r.nextInt(100) + 5;
Lattice lattice = new GeneralLattice(Matrix.random(n, n));
Matrix G = lattice.getGeneratorMatrix();
Mbest instance = new Mbest(lattice, n);
Babai babai = new Babai(lattice);
// System.out.println("G is " + G.getRowDimension() + " by " + G.getColumnDimension());
double[] x = new double[G.getRowDimension()];
double[] xdel = new double[G.getRowDimension()];
double[] u = new double[n];
for (int i = 0; i < n; i++) {
u[i] = r.nextDouble();
}
VectorFunctions.matrixMultVector(G, u, xdel);
instance.nearestPoint(xdel);
babai.nearestPoint(xdel);
double instdist = VectorFunctions.distance_between2(instance.getLatticePoint(), xdel);
double babaidist = VectorFunctions.distance_between2(babai.getLatticePoint(), xdel);
System.out.println(babaidist + ", " + instdist);
// System.out.println(VectorFunctions.print(babai.getIndex()));
assertTrue(instdist <= babaidist);
}
}