Hydrological Cycle Algorithm for Continuous Optimization Problems

Table 1

A summary of the main differences between IWD, WCA, and HCA.

Criteria	IWD	WCA	HCA
Flow stage	Moving water drops	Changing streams' positions	Moving water drops
Choosing the next node	Based on the soil	Based on river and sea positions	Based on soil and path depth
Velocity	Always increases	N/A	Increases and decreases
Soil update	Removal	N/A	Removal and deposition
Carrying soil	Equal to the amount of soil removed from a path	N/A	Is encoded with the solution quality
Evaporation	N/A	When the river position is very close to the sea position	Based on the temperature value, which is affected by the percentage of improvements in the last set of iterations
Evaporation rate	N/A	If the distance between a river and the sea is less than the threshold	Random number
Condensation	N/A	N/A	Enable information sharing (direct communication). Update the global-best solution, which is used to identify the collector
Precipitation	N/A	Randomly distributes a number of streams	Reinitializes dynamic parameters such as soil, velocity, and carrying soil