def optimize_orientations(fwtour, clm, phase, cpus):
    """
    Optimize the orientations of contigs by using heuristic flipping.
    """
    # Prepare input files
    tour_contigs = clm.active_contigs
    tour = clm.tour
    oo = clm.oo

    print_tour(fwtour, tour, "FLIPALL{}".format(phase),
               tour_contigs, oo, signs=clm.signs)
    tag1 = clm.flip_whole(tour)
    print_tour(fwtour, tour, "FLIPWHOLE{}".format(phase),
               tour_contigs, oo, signs=clm.signs)
    tag2 = clm.flip_one(tour)
    print_tour(fwtour, tour, "FLIPONE{}".format(phase),
               tour_contigs, oo, signs=clm.signs)

    return tag1, tag2
Optimize the orientations of contigs by using heuristic flipping.