Algorithm 3.

hopping HDA

Initialize: ν=0, u=0, s=0, t=0.
While “${\Vert \mathit{f}-\mathit{A}\mathit{u}\Vert }_2^2$ not converge” do
	r = max|νi|,
	j = argmaxi|νi|,
	if r<λ then
		$t_w=\text{min}[(\lambda \text{sign}({\mathit{A}}_i^T\mathit{f})-{\nu }_i)/({\mathit{A}}_i^T\mathit{f})]$,
		$j={\text{argmin}}_i[(\lambda \text{sign}({\mathit{A}}_i^T\mathit{f})-{\nu }_i)/({\mathit{A}}_i^T\mathit{f})]$,
		t ← t + tw,
		$s_j\leftarrow \text{sign}({\mathit{A}}_j^T\mathit{f})$
		ν ← ν + twATf − λsjATAj,
		uj ← ((t − 1)uj + sj)/t,
	else
		sj ← sign(νj)
		ν ← ν − λATAjsj,
		uj ← ((t − 1)uj + λsj)/t,
	end if
end while