From: Overview of constrained PARAFAC models
Models
Scalar writings
Mode‐ n product‐based writings
PARAFAC‐3
x i 1 , i 2 , i 3 = ∑ r R a i 1 , r ( 1 ) a i 2 , r ( 2 ) a i 3 , r ( 3 )
X= I 3 , R × 1 A ( 1 ) × 2 A ( 2 ) × 3 A ( 3 )
Tucker‐3
x i 1 , i 2 , i 3 = ∑ r 1 = 1 R 1 ∑ r 2 = 1 R 2 ∑ r 3 = 1 R 3 g r 1 , r 2 , r 3 a i 1 , r 1 ( 1 ) a i 2 , r 2 ( 2 ) a i 3 , r 3 ( 3 )
X=G × 1 A ( 1 ) × 2 A ( 2 ) × 3 A ( 3 )
Tucker‐(2,3)
x i 1 , i 2 , i 3 = ∑ r 1 = 1 R 1 ∑ r 2 = 1 R 2 g r 1 , r 2 , i 3 a i 1 , r 1 ( 1 ) a i 2 , r 2 ( 2 )
X=G × 1 A ( 1 ) × 2 A ( 2 )
PARALIND/CONFAC‐3
g r 1 , r 2 , r 3 = ∑ r R φ r 1 , r ( 1 ) φ r 2 , r ( 2 ) φ r 3 , r ( 3 )
G= I 3 , R × 1 Φ ( 1 ) × 2 Φ ( 2 ) × 3 Φ ( 3 )
PARATUCK‐2
g r 1 , r 2 , i 3 = c r 1 , r 2 φ r 1 , i 3 ( 1 ) φ r 2 , i 3 ( 2 )
G= I 3 , R × 1 Ψ ( 1 ) × 2 Ψ ( 2 ) × 3 F, R=R1R2
Ψ ( 1 ) = I R 1 ⊗ 1 R 2 T , Ψ ( 2 ) = 1 R 1 T ⊗ I R 2
F=(Φ(1)◇Φ(2))Tdiag(vec(CT))
PARATUCK‐(2,4)
x i 1 , i 2 , i 3 , i 4 = ∑ r 1 = 1 R 1 ∑ r 2 = 1 R 2 g r 1 , r 2 , i 3 , i 4 a i 1 , r 1 ( 1 ) a i 2 , r 2 ( 2 )
g r 1 , r 2 , i 3 , i 4 = c r 1 , r 2 , i 4 φ r 1 , i 3 ( 1 ) φ r 2 , i 3 ( 2 )
G= I 4 , R × 1 Ψ ( 1 ) × 2 Ψ ( 2 ) × 3 F × 4 D, R=R1R2
F= ( Φ ( 1 ) ◇ Φ ( 2 ) ) T ,D= C I 4 × R 1 R 2