Modeling Multilevel Supplier Selection Problem Based on Weighted-Directed Network and Its Solution

Table 3

The solutions of ant colony algorithm before and after improvement.

Network scale	Algorithm	Minimum	Maximum	Average	Variance	Convergence frequency
30 nodes	Ant colony	426.42	497.13	427.04	3.03	340.00
	Improved; ant colony	425.8	491.48	426.44	2.6956	530