"分段依次计算法" can be translated into English as "sequential calculation by segments" or "piecewise sequential calculation method".
"Sequential calculation by segments" emphasizes the step-by-step or sequential nature of the calculation process, with each step or segment being calculated in order.
"Piecewise sequential calculation method" adds more clarity by explicitly mentioning that the calculation is done in a piecewise (i.e., segmented) manner and is sequential.
Both translations are acceptable, and the choice between them may depend on the specific context and the level of detail required.