Algorithm 3 Fast-GPU-PCC
Input:$N\times M$ matrix U of time series data
Output: Correlation array C of size $N(N-1)/2$
1:	Preprocess the fMRI data using Equation (3)
2:	Copy normalized data to GPU global memory
3:	$B=X/2N$
4:	if $B>N$ then
5:	Multiply matrix U to its transpose $U^T$
6:	Extract upper triangle part of the matrix using Algorithm 1
7:	Transfer the correlation array to CPU
8:	else
9:	$i=0$, $N^{\prime }=N$
10:	while $i<N$ do
11:	Multiply rows i to $i+B$ of matrix U to columns i to N of $U^T$
12:	Extract the upper triangle part of correlation matrix using Algorithm 2
13:	Transfer the extracted correlations to CPU
14:	$i=i+B$
15:	$N^{\prime }=N^{\prime }-B$
16:	$B=X/2N^{\prime }$
17:	if $B>N^{\prime }$ then
18:	$B=N^{\prime }$
19:	end if
20:	end while
21:	end if