| Initialization |
| Initialize root populations, each consists of individuals. And set the maximum iteration number MaxT. |
| Set . |
| Calculate auxin concentration values of all populations by (2). |
| While (terminal conditions not satisfied) |
| Divide each population into main root and lateral root groups according to auxin concentration. |
| For each population |
| Construct Von Neumann topology as shown in Algorithm 1. |
| For each main roots group |
| Implement regrowing operator by (9). |
| Evaluate auxin concentration values of renewal main roots, and apply greedy selection. |
| If the condition of branching determined by (4) is met, continue; otherwise, go to lateral-roots loop. |
| Calculate the branching number by (5), and branching new roots by (6). |
| Adjust the population size. |
| End for |
| Loop over each mainroot tip |
| For each Lateral-roots group. |
| Lateral-root take regrowing operator by (7). |
| Evaluate the auxin concentration values of the renewal lateral roots, apply greedy selection. |
| Adjust the corresponding nutrient concentration value by (2); |
| End for |
| Loop over each root tip of lateral-roots |
| Remove the dead individuals from each population according to their auxin concentration values by (8). |
| Loop over each population |
| ; |
| End while |
| Output the best result. |
