“…Similar constraints on enforcing the placed locations of matched cells include commoncentroid [19,33,38], regularity [7,26,39], proximity [6,18,25,[33][34][35]41] and etc. Constraints such as monotonic current flow [28,31,36] and thermal effects [19,20] have also been studied to ensure circuit performance. To ensuring the placement solutions can fit to the design floorplan, boundary constraint [14,24,25,34,35], pre-placed constrains [24,25,34,35] and etc.…”