24 Algorithms library [algorithms]

24.9 Generalized numeric operations [numeric.ops]

24.9.1 Definitions [numerics.defns]

Define GENERALIZED_­NONCOMMUTATIVE_­SUM(op, a1, ..., aN) as follows:
  • a1 when N is 1, otherwise
  • op(GENERALIZED_­NONCOMMUTATIVE_­SUM(op, a1, ..., aK),
    op(GENERALIZED_­NONCOMMUTATIVE_­SUM(op, aM, ..., aN)) for any K where .
Define GENERALIZED_­SUM(op, a1, ..., aN) as GENERALIZED_­NONCOMMUTATIVE_­SUM(op, b1, ..., bN), where b1, ..., bN may be any permutation of a1, ..., aN.