Table 2 Comparison of computational complexity (\(s = \frac{n}{2}\)).

From: Optimized quantum folding Barrett reduction for quantum modular multipliers

Algorithm

Multiplication \(\{times[bits]\}\)

Addition/Subtraction \(\{times[bits]\}\)

General Barrett Reduction

\(1 [(2s+1)\times (2s+1)]\)

\(1 [(2s+1)-(2s+1)]\)

\(1 [(2s+1)\times 2s]\)

\(1 [(2s+2)-(2s+2)]\)

 

\(1 [(2s+2)+(2s+2)]\)

Folding Barrett Reduction

\(1 [s\times 2s]\)

\(1 [3s+3s]\)

\(1 [(s+1)\times (s+1)]\)

\(1 [(2s+1)-(2s+1)]\)

\(1 [(s+2)\times 2s]\)

\(3 [(2s+2)-(2s+2)]\)

 

\(1 [(2s+2)+(2s+2)]\)

Optimized Folding Barrett Reduction

\(1 [s\times 2s]\)

\(1 [3s+3s]\)

\(1 [(s+3)\times (s+4)]\)

\(1 [(2s+1)-(2s+1)]\)

\(1 [(s+2)\times 2s]\)

\(3 [(2s+2)-(2s+2)]\)

 

\(1 [(2s+2)+(2s+2)]\)