双向搜索 meaning in English

bidirectional research
bidirectional search

According to the relation between searching step and adjusting step , step - advance following can be divided into four kinds : memory - extemum tracking , same - step - advance tracking , both - direction - search - equal - adjustment step tracking , both - direction - search - changeable - adjustment step tracking . in this system , by analyzing and comparing , we select the mode of both - direction - search - equal - adjustment step tracking
根据搜索步和调整步之间的关系，可把步进跟踪分为四种：记忆极值式跟踪、同一步步进式跟踪、双向搜索等调整步式步进跟踪和双向搜索变调整步式步进跟踪。