. 2023 Nov 7;24:420. doi: 10.1186/s12859-023-05490-y

Table 4.

Order of calculation time and memory space for cell–cell interaction (CCI) identification

Method	Calculation time	Memory space
Sum/product score	$O (N^{2} L)$	$O (N^{2} L)$
Permutation test of sum/product score	$O (N^{2} L P)$	$O (N^{2} L)$
Halpern’s score	$O (N^{2} L)$	$O (N^{2} L)$
Permutation test of Halpern’s score	$O (N^{2} L P)$	$O (N^{2} L)$
Cabello $-$ Aguilar’s score	$O (N^{2} L)$	$O (N^{2} L)$
Permutation test of Cabello $-$ Aguilar’s score	$O (N^{2} L P)$	$O (N^{2} L)$
Previous scTensor (NTD-3)	$O (N^{2} L (R 1 + R 2 + R 3))$	$O (N^{2} L)$
scTensor (NTD-2)	$O (N^{2} L (R 1 + R 2))$	$O (N^{2} L)$