Abstract
A design strategy is discussed in this paper, and it provides much convenience for effectively exploring achievable linear optics and globally investigating the flexibility of a complex lattice with super-periodicity. A matching method of fractional steps, which means separately finding the standard cell setting and the matching cell setting, is adopted to simplify the complexity of the linear beam optics design in the complex lattice. The multi-objective genetic algorithm is used to find most of all the stable linear optics, and reach a target solution after multi-generational propagation, both in the standard cell and the matching cell. A fitting algorithm with gradient information is used to restore the periodicity and symmetry of the lattice, and finely adjust the linear optics for further optimization. This design strategy is applied in the Shanghai Synchrotron Radiation Facility (SSRF) storage ring, and the results are presented.