Table 2.

Comparison of run times for alkane isomers

Molecule	$n_{\text{consti}}$	$t_{\text{surge}}$ [s]		$t_{\text{enu}}$ [s]		$t_{\text{MAYGEN}}$ [s]
		No output	SMILES	No output	SMILES	No output	SMILES
${\text{C}}_1{\text{H}}_4$	1	< 0.01	< 0.01	< 0.01	< 0.01	< 0.01	0.10
${\text{C}}_2{\text{H}}_6$	1	< 0.01	< 0.01	< 0.01	0.01	0.06	0.14
${\text{C}}_3{\text{H}}_8$	1	< 0.01	< 0.01	< 0.01	< 0.01	0.05	0.13
${\text{C}}_4{\text{H}}_{10}$	2	< 0.01	< 0.01	< 0.01	< 0.01	0.05	0.13
${\text{C}}_5{\text{H}}_{12}$	3	< 0.01	< 0.01	< 0.01	0.01	0.06	0.16
${\text{C}}_6{\text{H}}_{14}$	5	< 0.01	< 0.01	< 0.01	< 0.01	0.07	0.17
${\text{C}}_7{\text{H}}_{16}$	9	< 0.01	< 0.01	< 0.01	< 0.01	0.09	0.20
${\text{C}}_8{\text{H}}_{18}$	18	< 0.01	< 0.01	< 0.01	< 0.01	0.14	0.29
${\text{C}}_9{\text{H}}_{20}$	35	< 0.01	< 0.01	< 0.01	< 0.01	0.27	0.52
${\text{C}}_{10}{\text{H}}_{22}$	75	<0.01	< 0.01	< 0.01	< 0.01	0.69	0.96
${\text{C}}_{11}{\text{H}}_{24}$	159	< 0.01	< 0.01	< 0.01	0.01	0.92	1.44
${\text{C}}_{12}{\text{H}}_{26}$	355	< 0.01	< 0.01	< 0.01	0.01	1.56	2.64
${\text{C}}_{13}{\text{H}}_{28}$	802	< 0.01	< 0.01	0.02	0.03	2.06	4.31
${\text{C}}_{14}{\text{H}}_{30}$	1858	0.01	0.02	0.05	0.07	4.15	6.91
${\text{C}}_{15}{\text{H}}_{32}$	4347	0.04	0.04	0.13	0.18	11.41	20.04
${\text{C}}_{16}{\text{H}}_{34}$	10359	0.11	0.12	0.31	0.40	45.79	74.30
${\text{C}}_{17}{\text{H}}_{36}$	24894	0.27	0.29	0.93	1.16	190.40	279.11
${\text{C}}_{18}{\text{H}}_{38}$	60523	0.66	0.71	2.74	3.17	1247.30	1637.19
${\text{C}}_{19}{\text{H}}_{40}$	148284	1.85	1.98	8.22	9.37	4146.88	6124.98
${\text{C}}_{20}{\text{H}}_{42}$	366319	5.27	5.63	25.55	33.87	–	–
${\text{C}}_{21}{\text{H}}_{44}$	910726	15.45	16.39	79.41	104.05	–	–
${\text{C}}_{22}{\text{H}}_{46}$	2278658	46.73	49.14	253.57	273.27	–	–
${\text{C}}_{23}{\text{H}}_{48}$	5731580	147.63	154.90	834.42	927.93	–	–
${\text{C}}_{24}{\text{H}}_{50}$	14490245	449.20	465.13	2895.93	2997.59	–	–
${\text{C}}_{25}{\text{H}}_{52}$	36797588	1347.30	1388.39	10040.19	10455.26	–	–

The table shows the number $n_{\text{consti}}$ of constitutional isomers of the straight-chain alkanes from ${\text{C}}_1{\text{H}}_4$ to ${\text{C}}_{25}{\text{H}}_{52}$, as well as the wall-clock time spent on their enumeration using the three programs surge ($t_{\text{surge}}$), enu ($t_{\text{enu}}$), and MAYGEN ($t_{\text{MAYGEN}}$). The elapsed wall-clock time is reported both for the case when no output is generated as well as the case when the SMILES strings of the isomers are reported. All calculations were performed on AMD EPYC 7763 CPUs of the ETH Zürich Euler cluster [40] and averaged over five runs. Note that the MAYGEN calculations were stopped after exceeding ${10}^4$ s. The results are illustrated graphically in Fig. 15