@Test
public void testQR() {
AMatrix a = Matrixx.createRandomMatrix(5, 4);
AMatrix[] ms = QR.decompose(a);
AMatrix q = ms[0];
AMatrix r = ms[1];
// we are testing that A = QR
assertTrue(q.innerProduct(r).epsilonEquals(a));
// check properties of Q - should be orthogonal
assertTrue(q.hasOrthonormalColumns());
// assertTrue(q.isSquare()); // TODO: should be square??
// check properties of R - should be upper triangular
assertTrue(r.isUpperTriangular());
}
