Algorithm 1 Block relaxation algorithm for maximizing (5).

Initialize: (α(0), γ(0)) = argmaxα,γ ℓ(α, γ, 0, …, 0), a random matrix for d = 1, …, D.

repeat

for d = 1, …, D do

${\mathit{B}}_d^{(t+1)}={\text{argmax}}_{{\mathit{B}}_d}\ell ({\alpha }^{\left(t\right)},{\gamma }^{\left(t\right)},{\mathit{B}}_1^{(t+1)},\dots ,{\mathit{B}}_{d-1}^{(t+1)},{\mathit{B}}_d,{\mathit{B}}_{d+1}^{\left(t\right)},\dots ,{\mathit{B}}_D^{\left(t\right)})$

end for

$({\alpha }^{(t+1)},{\gamma }^{(t+1)})={\text{argmax}}_{\alpha ,\gamma }\ell (\alpha ,\gamma ,{\mathit{B}}_1^{(t+1)},\dots ,{\mathit{B}}_D^{(t+1)})$

until ℓ(θ(t+1)) − ℓ(θ(t)) < ∊