MFSideData.py 文件源码

def SGD(x):
    global n_updates_acc
    global mse
    for val in x:
        row_block_id = val[0]
        v_iter = val[1][0]
        w_iter = val[1][1]
        h_iter = val[1][2]
    # dictionaries to store W and H
    w = {xw[0]:xw[1] for xw in w_iter}
    h = {xh[0]:xh[1] for xh in h_iter}
    # go through V and update W and H
    for v_ij in v_iter:
        i, j = v_ij
        # get row and column
        w_i = w[i]
        h_j = h[j]
        # calculate error
        error = 5 - np.dot(w_i,h_j)
        # increment MSE
        mse += error**2
        # gradients with L2 loss
        # dictionary values are updated in place
        h_update = step_size.value*(-2*error*w_i + 2.0*reg.value*h_j)
        h_update_mx = ma.masked_array(h_update, mask.value)
        w_update = step_size.value*(-2*error*h_j + 2.0*reg.value*w_i)
        h_j -= step_size.value*(-2*error*w_i + 2.0*reg.value*h_j)
        w_i -= step_size.value*(-2*error*h_j + 2.0*reg.value*w_i)
        # increment num updates
        n_updates_acc += 1
    # must massage results in something that will return properly
    output = {}
    for row_index in w:
        output[('W', row_index)] = (row_index, w[row_index])
    for col_index in h:
        output[('H', col_index)] = (col_index, h[col_index])
    # return iterator of updated W and H
    return tuple((output.items()))