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Table 2 Comparison of the maximum approximation ratios given by the EH algorithm with ours (Alg1)

From: A new 1.375-approximation algorithm for sorting by transpositions

n

Transposition diameter

Max. approx.ratio

Averageapprox. ratio

Average distance

Number of times EH exceeded the 1.375-approx.

Time to sort all permutationsa

EH

Alg1

EH

Alg1

EH

Alg1

EH

Alg1

2

1

1.00

1.00

1.0

1.0

1.00

1.00

0

\(<1s\)

\(<1s\)

3

2

1.00

1.00

1.0

1.0

1.20

1.20

0

\(<1s\)

\(<1s\)

4

3

1.00

1.00

1.0

1.0

1.6086

1.6086

0

\(<1s\)

\(<1s\)

5

3

1.00

1.00

1.0

1.0

2.0924

2.0924

0

\(<1s\)

\(<1s\)

6

4

\(1.333{\bar{3}}\)

1.00

1.0004

1.0

2.6063

2.6050

0

\(<1s\)

\(<1s\)

7

5

\(1.333{\bar{3}}\)

1.25

1.0129

1.0113

3.1762

3.1704

0

\(<1s\)

\(<1s\)

8

6

1.5

1.25

1.0210

1.0183

3.7178

3.7076

2

\(<2s\)

\(<2s\)

9

6

1.5

1.25

1.0301

1.0256

4.2796

4.2603

20

\(\approx 10s\)

\(\approx 13s\)

10

7

1.5

1.25

1.0341

1.0282

4.8051

4.7772

110

\(\approx 3m\)

\(\approx 2m\)

11

8

1.5

\(1.333{\bar{3}}\)

1.0392

1.0321

5.3526

5.3157

440

\(\approx 35m\)

\(\approx 30m\)

12

9

1.5

\(1.333{\bar{3}}\)

1.0415

1.0336

5.8694

5.8248

1448

\(\approx 8.5h\)

\(\approx 8.1h\)

  1. The table includes other metrics such as the average approximation ratio and average distance given by each algorithm and the number of times the EH algorithm exceeds the 1.375-approximation ratio as well as the time consumed by each algorithm to sort all permutations of each size. Decimal values are truncated to 4 places
  2. a The permutations of each size were sorted in parallel using a pool of 8 threads