['There', 'are', 'other', 'methods', 'to', 'calculate', 'the', 'stress', 'tensor', 'such', 'as', 'the', 'method', 'of', 'planes', '[', '32', ']', ',', 'the', 'volume', '-', 'average', 'approach', '[', '26,14', ']', ',', 'or', 'the', 'method', 'derived', 'from', 'the', 'Schweitz', 'virial', 'relation', '[', '25', ']', ',', 'but', ',', 'in', 'general', ',', 'we', 'must', 'choose', 'between', 'a', 'complicated', 'computational', 'cell', '(', 'i.e.', 'Lees', '–', 'Edwards', 'cell', ')', 'and', 'simplifying', 'the', 'calculation', 'of', 'the', 'momentum', 'flux', ',', 'or', 'a', 'simple', 'cell', '(', 'i.e.', 'framed', 'cell', ')', 'and', 'complicating', 'the', 'calculation', 'of', 'the', 'momentum', 'flux', '.']