@Test
public void test1() {

    BackFilter f=BackFilter.of(new double[]{1, -.2});
    SymmetricFilter sf=SymmetricFilter.createFromFilter(f);
    SymmetricMullerNewtonSolver solver=new SymmetricMullerNewtonSolver();
    Polynomial P = Polynomial.copyOf(sf.getWeights());
    Complex[] roots = P.roots(solver);
      for (int i=0; i<roots.length; ++i){
          System.out.println(roots[i]);
      }
}