“…Minimizing a sum of convex functions, where each component is known only to a particular node, has attracted much attention recently, due to its simple formulation and wide applications [22], [20], [21], [26], [27], [23], [31], [30], [28], [29], [32], [25], [24]. The key idea is that properly designed distributed control protocols or computation algorithms can lead to a collective optimization, based on simple exchanged information and individual optimum observation.…”