例:K-means Hashing提供的代碼optimize_one_iter函數(shù)內(nèi)部用到fminunc,代價(jià)函數(shù)是eval_one_center函數(shù),看eval_one_center函數(shù)的注釋是this function computes the cost of Eqn. (8) given a center c_j