Fig. 3.

Pipeline of stochastic coordinate coding algorithm. In k-th iteration, given one FCV x_i, ① a few steps of coordinate descent (CD) are performed to find the support of the sparse code. ② A few more steps of coordinate descent (CD) are implemented on the supports to obtain a new sparse code $z_i^k$ ③ The supports of the dictionary are updated by second order stochastic gradient descent (SGD).