| | DATA: a population P matrix of initially randomly generated tours where tour = P[1, :] Size of the population is m and the length of any tour is n. |
| | The distance function Distance (launch, deliver, rendezvous) determines the total distance between the nodes in the |
| | RESULT: an ∼ optimal tour for the nodes [1 : n]. |
| | FOR iter 1 to Budget LOOP |
| | FOR p in m LOOP (for each population of tours) |
| | ⟵ P[p, :]; (a tour within the population of tours) |
| | ⟵ P[p, 1 : n, 1, 2, 3]; (add wrap back around to depot to tour) |
| | ⟵ 0; (initialize total tour time for this tour) |
| | WHILE i ≤ n DO (go through each of the nodes in tour) |
| | case ⟵ 1; (initialize default case: truck carries drone and delivers) |
| | launch ⟵ (i); (truck launch node) |
| | deliver ⟵ (i + 1); (drone delivery node) |
| | rendezvous ⟵ (i + 1); (truck and drone rendezvous node) |
| | launch fathom ⟵ (i + 1); (check next operation truck launch node) |
| | deliver fathom ⟵ (i + 2); (check next operation drone delivery node) |
| | rendezvous fathom ⟵ (i + 3); (check next operation truck/drone rendezvous node) |
| | drone dist ⟵ Distance (launch, deliver, rendezvous) |
| | truck dist ⟵ Distance (launch, , rendezvous) |
| | IF drone dist <range AND i + 1 ≤ n THEN |
| | case ⟵ 2; |
| | fathom 1 ⟵ max[(drone dist)/(drone speed), (truck dist)/(truck speed)] |
| | drone dist 2 ⟵ Distance (fathom launch, fathom deliver, fathom rendezvous) |
| | truck dist 2 ⟵ Distance (fathom launch, , fathom rendezvous) |
| | fathom 2 ⟵ max[(drone dist 2)/(drone speed), (truck dist 2)/(truck speed)] |
| | IF drone dist 2 < range AND fathom 2 < fathom 1 AND i + 2 ≤ n THEN |
| | case ⟵ 1; (save drone for next operation, set to truck deliver for this iteration) |
| | drone dist ⟵ 0; (no drone distance) |
| | END IF |
| | ELSE |
| | drone dist ⟵ 0; (out of drone range…) |
| | END IF |
| | SWITCH CASE |
| | CASE == 1 (truck delivers) |
| | truck dist := Distance (launch, , deliver); (find truck distance to next node) |
| | k ⟵ k + 1; |
| | CASE == 2 (truck and drone deliver) |
| | truck dist := Distance (launch, , rendezvous); (find truck distance to rendezvous) |
| | drone dist := Distance (launch, deliver, rendezvous); (find drone distance for operation) |
| | k ⟵ k + 2; (two nodes satisfied) |
| | END CASE |
| | = + max[(drone dist)/(drone speed), (truck dist)/(truck speed)] (capture and record the total time for population member p) |
| | END WHILE LOOP |
| | END FOR LOOP |
| | P ⟵ randomly shuffle rows in population matrix P for a tournament (do not change tours) |
| | FOR p = 5 : 5 : m LOOP (select groups comprised of 5 tours each from the population P of size m) |
| | Best time ⟵ Get Best Time (P[p, :]) for the group of the 5 tours |
| | Best Id ⟵ Find route id of the group of 5 having the best time (Best Time) |
| | Pʹ[p1,2,3,4,5, :] ⟵ Replace all tours in population group P(p, :) with fittest tour of the 5 tours. |
| | Pʹ [p1, :] ⟵ keep (do not mutate) the fittest tour of the group of 5 (keep for next iteration) |
| | Pʹ[p2,3,4,5, :] ⟵ Mutate the other 4 less fit tours as follows: |
| | (1) tour 1: randomly select 2 points in the route Pʹ[p2, :] to swap |
| | (2) tour 2: randomly select 2 points Pʹ[p3, :]to reverse all nodes in between |
| | (3) tour 3: randomly select 2 points in route Pʹ[p4, :]to slide to left and replace last with first |
| | (4) tour 4: replace the first and last nodes Pʹ[p5, :]with two randomly selected nodes |
| | END FOR LOOP |
| | P ⟵ update P with all mutations P′ |
| | END FOR LOOP |
| | RETURN best and best route found in population |
