“…These methods have attracted considerable attention in the past few years, and include SCD [69], RCDM [49], UCDC [59], ICD [77], PCDM [60], SPCDM [14], SPDC [86], APCG [37], RCD [44], APPROX [15], QUARTZ [55] and ALPHA [53]. Recent advances on mini-batch and distributed variants can be found in [38], [90], [58], [16], [79], [25], [43] and [41]. Other related work includes [47,13,1,89,17,76].…”