code: protected static int fixRoots (float[] res, int rc) {
          int tc = 0;
          for (int i = 0; i < rc; i++) {
              out: {
                  for (int j = i + 1; j < rc; j++) {
                      if (isZero(res[i] - res[j])) {
                          break out;
                      }
                  }
                  res[tc++] = res[i];
              }
          }
          return tc;
      }
docs: Excludes double roots. Roots are double if they lies enough close with each other.
  
  @param res the roots
  @param rc the roots count
  @return new roots count