Algorithm 1.

EM-TV [29] with ordered subsets

1:	input y and s
2:	initialize u > 0
3:	for n = 1… ni do
4:	for k = 1… ns do
5:	$\mathit{d}=\frac{\mathit{u}}{{\mathit{P}}_k^{\ast }1}{\mathit{P}}_k^{\ast }\frac{{\mathit{y}}_k}{{\mathit{P}}_k\mathit{u}+{\mathit{s}}_k}$
6:	$w_j={\displaystyle \sum _i}{P}_{ij}/(\beta u_j)$
7:	${\mathit{u}}^{+}=\text{arg}\underset{\mathit{u}\ge 0}{min}{\displaystyle \sum _j}\frac{w_j}{2}{(u_j-d_j)}^2+R(\mathit{u})$
8:	u = u+
9:	end for
10:	end for
11:	return u