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[BUG]: Tabu search doesn't update correctly #163

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ericho-bbai opened this issue Aug 20, 2024 · 2 comments · May be fixed by #164
Closed

[BUG]: Tabu search doesn't update correctly #163

ericho-bbai opened this issue Aug 20, 2024 · 2 comments · May be fixed by #164
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@thieu1995
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@ericho-bbai
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ericho-bbai commented Aug 20, 2024 •
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Description of the bug

The global and current best fitness stays the same during optimization. The issue is that TS.OriginalTS.pop needs to be updated so that the base Optimizer class can optimize properly.

Steps To Reproduce

Run tabu search example:

import numpy as np
from mealpy import FloatVar, TS

def objective_function(solution):
    res = np.sum(solution**2)
    return res

problem_dict = {
    "bounds": FloatVar(lb=(-10.,) * 2, ub=(10.,) * 2, name="delta"),
    "minmax": "min",
    "obj_func": objective_function,
}

model = TS.OriginalTS(epoch=10, pop_size=5, tabu_size = 3, neighbour_size = 7, perturbation_scale = 0.05)
g_best = model.solve(problem_dict)
print(f"Solution: {model.g_best.solution}, Fitness: {model.g_best.target.fitness}")

Output example:

2024/08/20 12:38:04 PM, INFO, mealpy.math_based.TS.OriginalTS: Solving single objective optimization problem.
2024/08/20 12:38:04 PM, INFO, mealpy.math_based.TS.OriginalTS: >>>Problem: P, Epoch: 1, Current best: 6.724059899786338, Global best: 6.724059899786338, Runtime: 0.00223 seconds
2024/08/20 12:38:04 PM, INFO, mealpy.math_based.TS.OriginalTS: >>>Problem: P, Epoch: 2, Current best: 6.724059899786338, Global best: 6.724059899786338, Runtime: 0.00223 seconds
2024/08/20 12:38:04 PM, INFO, mealpy.math_based.TS.OriginalTS: >>>Problem: P, Epoch: 3, Current best: 6.724059899786338, Global best: 6.724059899786338, Runtime: 0.00256 seconds
2024/08/20 12:38:04 PM, INFO, mealpy.math_based.TS.OriginalTS: >>>Problem: P, Epoch: 4, Current best: 6.724059899786338, Global best: 6.724059899786338, Runtime: 0.00130 seconds
2024/08/20 12:38:04 PM, INFO, mealpy.math_based.TS.OriginalTS: >>>Problem: P, Epoch: 5, Current best: 6.724059899786338, Global best: 6.724059899786338, Runtime: 0.00295 seconds
2024/08/20 12:38:04 PM, INFO, mealpy.math_based.TS.OriginalTS: >>>Problem: P, Epoch: 6, Current best: 6.724059899786338, Global best: 6.724059899786338, Runtime: 0.00217 seconds
2024/08/20 12:38:04 PM, INFO, mealpy.math_based.TS.OriginalTS: >>>Problem: P, Epoch: 7, Current best: 6.724059899786338, Global best: 6.724059899786338, Runtime: 0.00121 seconds
2024/08/20 12:38:04 PM, INFO, mealpy.math_based.TS.OriginalTS: >>>Problem: P, Epoch: 8, Current best: 6.724059899786338, Global best: 6.724059899786338, Runtime: 0.00115 seconds
2024/08/20 12:38:04 PM, INFO, mealpy.math_based.TS.OriginalTS: >>>Problem: P, Epoch: 9, Current best: 6.724059899786338, Global best: 6.724059899786338, Runtime: 0.00145 seconds
2024/08/20 12:38:04 PM, INFO, mealpy.math_based.TS.OriginalTS: >>>Problem: P, Epoch: 10, Current best: 6.724059899786338, Global best: 6.724059899786338, Runtime: 0.00098 seconds

Additional Information

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@ericho-bbai ericho-bbai added the bug Something isn't working label Aug 20, 2024
@ericho-bbai ericho-bbai mentioned this issue Aug 20, 2024
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@thieu1995
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Hi @ericho-bbai ,
This is normal behaviours from weak algorithms.

@ericho-bbai
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ericho-bbai commented Aug 29, 2024 •
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Hello @thieu1995, please see the linked PR. Those changes fixed this issue for me. Since the BaseOptimizer uses self.pop to optimize, the tabu list needs to be part of self.pop in some way.

Also, what are some strong algorithms in your opinion?

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[BUG] Fix Tabu Search optimization ericho-bbai/mealpy
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@thieu1995 @ericho-bbai