Multi-objective Fonseca-Fleming example with the mNBI algorithm

In this example, the modified Normal Boundary Intersection algorithm (mNBI) is used to solve the FonsecaFleming optimization problem [FF95]:

\[\begin{split}\begin{aligned} \text{minimize the objective function } & f_1(x) = 1 - exp(-\sum_{i=1}^{d}((x_i - 1 / sqrt(d)) ^ 2)) \\ & f_2(x) = 1 + exp(-\sum_{i=1}^{d}((x_i + 1 / sqrt(d)) ^ 2)) \\ \text{with respect to the design variables }&x\\ \text{subject to the bound constraint} & x\in[-4,4]^d \end{aligned}\end{split}\]

We also show how the Pareto front can be refined.

from __future__ import annotations

from gemseo import configure_logger
from gemseo import execute_algo
from gemseo import execute_post
from gemseo.problems.analytical.fonseca_fleming import FonsecaFleming

configure_logger()
<RootLogger root (INFO)>

Solve the Fonseca-Fleming optimization problem

The 3 sub-optimization problems of mNBI are solved with SLSQP, a gradient-based optimization algorithm from the NLOPT library, with a maximum of 100 iterations. The analytic gradients are provided.

opt_problem = FonsecaFleming()
result = execute_algo(
    opt_problem,
    "MNBI",
    max_iter=1000,
    sub_optim_max_iter=100,
    n_sub_optim=3,
    sub_optim_algo="NLOPT_SLSQP",
)
INFO - 13:54:28: Optimization problem:
INFO - 13:54:28:    minimize FonsecaFleming
INFO - 13:54:28:    with respect to x
INFO - 13:54:28:    over the design space:
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | Name | Lower bound | Value | Upper bound | Type  |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | x[0] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[1] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[2] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28: Solving optimization problem with algorithm MNBI:
INFO - 13:54:28: Searching for the individual optimum of each objective
INFO - 13:54:28: Optimization problem:
INFO - 13:54:28:    minimize f_0
INFO - 13:54:28:    with respect to x
INFO - 13:54:28:    over the design space:
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | Name | Lower bound | Value | Upper bound | Type  |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | x[0] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[1] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[2] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:      1%|          | 6/1000 [00:00<00:03, 302.98 it/sec, obj=[3.45593287e-09 9.81688668e-01]]
INFO - 13:54:28:      1%|          | 7/1000 [00:00<00:02, 333.98 it/sec, obj=[0.         0.98168436]]
INFO - 13:54:28:      1%|          | 8/1000 [00:00<00:02, 361.29 it/sec, obj=[0.         0.98168436]]
INFO - 13:54:28:      1%|          | 9/1000 [00:00<00:02, 400.53 it/sec, obj=[0.         0.98168436]]
INFO - 13:54:28: Optimization result:
INFO - 13:54:28:    Optimizer info:
INFO - 13:54:28:       Status: None
INFO - 13:54:28:       Message: Successive iterates of the objective function are closer than ftol_rel or ftol_abs. GEMSEO Stopped the driver
INFO - 13:54:28:       Number of calls to the objective function by the optimizer: 11
INFO - 13:54:28:    Solution:
INFO - 13:54:28:       Objective: 0.0
INFO - 13:54:28:       Design space:
INFO - 13:54:28:          +------+-------------+--------------------+-------------+-------+
INFO - 13:54:28:          | Name | Lower bound |       Value        | Upper bound | Type  |
INFO - 13:54:28:          +------+-------------+--------------------+-------------+-------+
INFO - 13:54:28:          | x[0] |      -4     | 0.577350268484795  |      4      | float |
INFO - 13:54:28:          | x[1] |      -4     | 0.577350268484795  |      4      | float |
INFO - 13:54:28:          | x[2] |      -4     | 0.5773502684847949 |      4      | float |
INFO - 13:54:28:          +------+-------------+--------------------+-------------+-------+
INFO - 13:54:28: Optimization problem:
INFO - 13:54:28:    minimize f_1
INFO - 13:54:28:    with respect to x
INFO - 13:54:28:    over the design space:
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | Name | Lower bound | Value | Upper bound | Type  |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | x[0] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[1] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[2] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:      1%|          | 10/1000 [00:00<00:03, 249.21 it/sec, obj=[0.95084904 0.06744148]]
INFO - 13:54:28:      1%|          | 11/1000 [00:00<00:03, 266.61 it/sec, obj=[0.99997026 0.77891095]]
INFO - 13:54:28:      1%|          | 12/1000 [00:00<00:03, 288.33 it/sec, obj=[0.98859846 0.01317993]]
INFO - 13:54:28:      1%|▏         | 13/1000 [00:00<00:03, 296.02 it/sec, obj=[9.81345634e-01 2.10356748e-05]]
INFO - 13:54:28:      1%|▏         | 14/1000 [00:00<00:03, 310.69 it/sec, obj=[9.81688668e-01 3.45593287e-09]]
INFO - 13:54:28:      2%|▏         | 15/1000 [00:00<00:03, 324.21 it/sec, obj=[0.98168436 0.        ]]
INFO - 13:54:28:      2%|▏         | 16/1000 [00:00<00:02, 337.72 it/sec, obj=[0.98168436 0.        ]]
INFO - 13:54:28:      2%|▏         | 17/1000 [00:00<00:02, 356.36 it/sec, obj=[0.98168436 0.        ]]
INFO - 13:54:28: Optimization result:
INFO - 13:54:28:    Optimizer info:
INFO - 13:54:28:       Status: None
INFO - 13:54:28:       Message: Successive iterates of the objective function are closer than ftol_rel or ftol_abs. GEMSEO Stopped the driver
INFO - 13:54:28:       Number of calls to the objective function by the optimizer: 11
INFO - 13:54:28:    Solution:
INFO - 13:54:28:       Objective: 0.0
INFO - 13:54:28:       Design space:
INFO - 13:54:28:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28:          | Name | Lower bound |        Value        | Upper bound | Type  |
INFO - 13:54:28:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28:          | x[0] |      -4     |  -0.577350268484795 |      4      | float |
INFO - 13:54:28:          | x[1] |      -4     |  -0.577350268484795 |      4      | float |
INFO - 13:54:28:          | x[2] |      -4     | -0.5773502684847949 |      4      | float |
INFO - 13:54:28:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28: Solving mNBI sub-problem for beta = [0.5 0.5]
INFO - 13:54:28: Optimization problem:
INFO - 13:54:28:    minimize -t_extraction
INFO - 13:54:28:    with respect to t, x
INFO - 13:54:28:    subject to constraints:
INFO - 13:54:28:       beta_sub_optim_constraint <= 0.0
INFO - 13:54:28:    over the design space:
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | Name | Lower bound | Value | Upper bound | Type  |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | x[0] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[1] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[2] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | t    |     -inf    |   0   |     inf     | float |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:      2%|▏         | 18/1000 [00:00<00:03, 265.02 it/sec, obj=[0.63212056 0.63212056]]
INFO - 13:54:28: Optimization result:
INFO - 13:54:28:    Optimizer info:
INFO - 13:54:28:       Status: None
INFO - 13:54:28:       Message: Successive iterates of the design variables are closer than xtol_rel or xtol_abs. GEMSEO Stopped the driver
INFO - 13:54:28:       Number of calls to the objective function by the optimizer: 4
INFO - 13:54:28:    Solution:
INFO - 13:54:28:       The solution is feasible.
INFO - 13:54:28:       Objective: 0.1439142599466381
INFO - 13:54:28:       Standardized constraints:
INFO - 13:54:28:          beta_sub_optim_constraint = [ 8.32667268e-17 -1.38777878e-16]
INFO - 13:54:28:       Design space:
INFO - 13:54:28:          +------+-------------+------------------------+-------------+-------+
INFO - 13:54:28:          | Name | Lower bound |         Value          | Upper bound | Type  |
INFO - 13:54:28:          +------+-------------+------------------------+-------------+-------+
INFO - 13:54:28:          | x[0] |      -4     | -6.407485192731112e-17 |      4      | float |
INFO - 13:54:28:          | x[1] |      -4     | -6.407485192731112e-17 |      4      | float |
INFO - 13:54:28:          | x[2] |      -4     | -6.407485192731112e-17 |      4      | float |
INFO - 13:54:28:          | t    |     -inf    |  -0.1439142599466381   |     inf     | float |
INFO - 13:54:28:          +------+-------------+------------------------+-------------+-------+
INFO - 13:54:28:      2%|▏         | 19/1000 [00:00<00:04, 226.56 it/sec, obj=[0.63212056 0.63212056]]
INFO - 13:54:28: Optimization result:
INFO - 13:54:28:    Optimizer info:
INFO - 13:54:28:       Status: None
INFO - 13:54:28:       Message: None
INFO - 13:54:28:       Number of calls to the objective function by the optimizer: 26
INFO - 13:54:28:    Solution:
INFO - 13:54:28:       Objective: 0.8939534673502061
INFO - 13:54:28:    Pareto efficient solutions:
INFO - 13:54:28:       Pareto optimal points : 6 / 19
INFO - 13:54:28:       Utopia point : [0. 0.]
INFO - 13:54:28:       Compromise solution (closest to utopia) : [[0.06744148 0.95084904]
INFO - 13:54:28:        [0.95084904 0.06744148]]
INFO - 13:54:28:       Distance from utopia : 0.9532377715846151
INFO - 13:54:28:       Objective values:
INFO - 13:54:28:          +------+----------+----------+-----------+-----------+
INFO - 13:54:28:          | name |        1 |        2 |         3 |         4 |
INFO - 13:54:28:          +------+----------+----------+-----------+-----------+
INFO - 13:54:28:          |    1 |        0 | 0.981684 | 0.0674415 |  0.950849 |
INFO - 13:54:28:          |    2 | 0.981684 |        0 |  0.950849 | 0.0674415 |
INFO - 13:54:28:          +------+----------+----------+-----------+-----------+
INFO - 13:54:28:       Design space:
INFO - 13:54:28:          +-------+-------------+---------+----------+----------+-----------+-------------+-------+
INFO - 13:54:28:          |  name | lower_bound |       1 |        2 |        3 |         4 | upper_bound |  type |
INFO - 13:54:28:          +-------+-------------+---------+----------+----------+-----------+-------------+-------+
INFO - 13:54:28:          | x (1) |          -4 | 0.57735 | -0.57735 | 0.424791 | -0.424791 |           4 | float |
INFO - 13:54:28:          | x (2) |          -4 | 0.57735 | -0.57735 | 0.424791 | -0.424791 |           4 | float |
INFO - 13:54:28:          | x (3) |          -4 | 0.57735 | -0.57735 | 0.424791 | -0.424791 |           4 | float |
INFO - 13:54:28:          +-------+-------------+---------+----------+----------+-----------+-------------+-------+

Display the Pareto front

GEMSEO detects the Pareto optimal points and the dominated ones. The Fonseca-Fleming problem is interesting because its Pareto front is not convex. The mNBI algorithm successfully computes it.

execute_post(opt_problem, "ParetoFront", save=False, show=True)
Pareto front
<gemseo.post.pareto_front.ParetoFront object at 0x7f28ec377ac0>

Solve the Fonseca-Fleming optimization problem more finely

The Pareto front is then refined with 10 sub-optimizations instead of 3.

opt_problem = FonsecaFleming()
result = execute_algo(
    opt_problem,
    "MNBI",
    max_iter=1000,
    sub_optim_max_iter=100,
    n_sub_optim=10,
    sub_optim_algo="NLOPT_SLSQP",
)
INFO - 13:54:28: Optimization problem:
INFO - 13:54:28:    minimize FonsecaFleming
INFO - 13:54:28:    with respect to x
INFO - 13:54:28:    over the design space:
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | Name | Lower bound | Value | Upper bound | Type  |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | x[0] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[1] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[2] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28: Solving optimization problem with algorithm MNBI:
INFO - 13:54:28: Searching for the individual optimum of each objective
INFO - 13:54:28: Optimization problem:
INFO - 13:54:28:    minimize f_0
INFO - 13:54:28:    with respect to x
INFO - 13:54:28:    over the design space:
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | Name | Lower bound | Value | Upper bound | Type  |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | x[0] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[1] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[2] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:      1%|          | 6/1000 [00:00<00:03, 310.34 it/sec, obj=[3.45593287e-09 9.81688668e-01]]
INFO - 13:54:28:      1%|          | 7/1000 [00:00<00:02, 342.09 it/sec, obj=[0.         0.98168436]]
INFO - 13:54:28:      1%|          | 8/1000 [00:00<00:02, 371.10 it/sec, obj=[0.         0.98168436]]
INFO - 13:54:28:      1%|          | 9/1000 [00:00<00:02, 411.26 it/sec, obj=[0.         0.98168436]]
INFO - 13:54:28: Optimization result:
INFO - 13:54:28:    Optimizer info:
INFO - 13:54:28:       Status: None
INFO - 13:54:28:       Message: Successive iterates of the objective function are closer than ftol_rel or ftol_abs. GEMSEO Stopped the driver
INFO - 13:54:28:       Number of calls to the objective function by the optimizer: 11
INFO - 13:54:28:    Solution:
INFO - 13:54:28:       Objective: 0.0
INFO - 13:54:28:       Design space:
INFO - 13:54:28:          +------+-------------+--------------------+-------------+-------+
INFO - 13:54:28:          | Name | Lower bound |       Value        | Upper bound | Type  |
INFO - 13:54:28:          +------+-------------+--------------------+-------------+-------+
INFO - 13:54:28:          | x[0] |      -4     | 0.577350268484795  |      4      | float |
INFO - 13:54:28:          | x[1] |      -4     | 0.577350268484795  |      4      | float |
INFO - 13:54:28:          | x[2] |      -4     | 0.5773502684847949 |      4      | float |
INFO - 13:54:28:          +------+-------------+--------------------+-------------+-------+
INFO - 13:54:28: Optimization problem:
INFO - 13:54:28:    minimize f_1
INFO - 13:54:28:    with respect to x
INFO - 13:54:28:    over the design space:
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | Name | Lower bound | Value | Upper bound | Type  |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | x[0] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[1] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[2] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:      1%|          | 10/1000 [00:00<00:03, 258.48 it/sec, obj=[0.95084904 0.06744148]]
INFO - 13:54:28:      1%|          | 11/1000 [00:00<00:03, 276.28 it/sec, obj=[0.99997026 0.77891095]]
INFO - 13:54:28:      1%|          | 12/1000 [00:00<00:03, 298.92 it/sec, obj=[0.98859846 0.01317993]]
INFO - 13:54:28:      1%|▏         | 13/1000 [00:00<00:03, 306.92 it/sec, obj=[9.81345634e-01 2.10356748e-05]]
INFO - 13:54:28:      1%|▏         | 14/1000 [00:00<00:03, 321.26 it/sec, obj=[9.81688668e-01 3.45593287e-09]]
INFO - 13:54:28:      2%|▏         | 15/1000 [00:00<00:02, 335.48 it/sec, obj=[0.98168436 0.        ]]
INFO - 13:54:28:      2%|▏         | 16/1000 [00:00<00:02, 349.21 it/sec, obj=[0.98168436 0.        ]]
INFO - 13:54:28:      2%|▏         | 17/1000 [00:00<00:02, 368.40 it/sec, obj=[0.98168436 0.        ]]
INFO - 13:54:28: Optimization result:
INFO - 13:54:28:    Optimizer info:
INFO - 13:54:28:       Status: None
INFO - 13:54:28:       Message: Successive iterates of the objective function are closer than ftol_rel or ftol_abs. GEMSEO Stopped the driver
INFO - 13:54:28:       Number of calls to the objective function by the optimizer: 11
INFO - 13:54:28:    Solution:
INFO - 13:54:28:       Objective: 0.0
INFO - 13:54:28:       Design space:
INFO - 13:54:28:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28:          | Name | Lower bound |        Value        | Upper bound | Type  |
INFO - 13:54:28:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28:          | x[0] |      -4     |  -0.577350268484795 |      4      | float |
INFO - 13:54:28:          | x[1] |      -4     |  -0.577350268484795 |      4      | float |
INFO - 13:54:28:          | x[2] |      -4     | -0.5773502684847949 |      4      | float |
INFO - 13:54:28:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28: Solving mNBI sub-problem for beta = [0.11111111 0.88888889]
INFO - 13:54:28: Optimization problem:
INFO - 13:54:28:    minimize -t_extraction
INFO - 13:54:28:    with respect to t, x
INFO - 13:54:28:    subject to constraints:
INFO - 13:54:28:       beta_sub_optim_constraint <= 0.0
INFO - 13:54:28:    over the design space:
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | Name | Lower bound | Value | Upper bound | Type  |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:       | x[0] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[1] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | x[2] |      -4     |   0   |      4      | float |
INFO - 13:54:28:       | t    |     -inf    |   0   |     inf     | float |
INFO - 13:54:28:       +------+-------------+-------+-------------+-------+
INFO - 13:54:28:      2%|▏         | 18/1000 [00:00<00:03, 273.33 it/sec, obj=[0.90043834 0.20664322]]
INFO - 13:54:28:      2%|▏         | 19/1000 [00:00<00:03, 282.12 it/sec, obj=[0.91873293 0.15869784]]
INFO - 13:54:28:      2%|▏         | 20/1000 [00:00<00:03, 290.70 it/sec, obj=[0.91966962 0.15614908]]
INFO - 13:54:28:      2%|▏         | 21/1000 [00:00<00:03, 299.15 it/sec, obj=[0.91967277 0.15614049]]
INFO - 13:54:28: Optimization result:
INFO - 13:54:28:    Optimizer info:
INFO - 13:54:28:       Status: None
INFO - 13:54:28:       Message: Successive iterates of the design variables are closer than xtol_rel or xtol_abs. GEMSEO Stopped the driver
INFO - 13:54:28:       Number of calls to the objective function by the optimizer: 7
INFO - 13:54:28:    Solution:
INFO - 13:54:28:       The solution is feasible.
INFO - 13:54:28:       Objective: 0.04794255057736304
INFO - 13:54:28:       Standardized constraints:
INFO - 13:54:28:          beta_sub_optim_constraint = [-9.53889745e-14  1.10154941e-13]
INFO - 13:54:28:       Design space:
INFO - 13:54:28:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:          | Name | Lower bound |        Value         | Upper bound | Type  |
INFO - 13:54:28:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:          | x[0] |      -4     | -0.3394642613023262  |      4      | float |
INFO - 13:54:28:          | x[1] |      -4     | -0.3394642613023261  |      4      | float |
INFO - 13:54:28:          | x[2] |      -4     |  -0.339464261302326  |      4      | float |
INFO - 13:54:28:          | t    |     -inf    | -0.04794255057736304 |     inf     | float |
INFO - 13:54:28:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28: Solving mNBI sub-problem for beta = [0.22222222 0.77777778]
INFO - 13:54:28: Optimization problem:
INFO - 13:54:28:    minimize -t_extraction
INFO - 13:54:28:    with respect to t, x
INFO - 13:54:28:    subject to constraints:
INFO - 13:54:28:       beta_sub_optim_constraint <= 0.0
INFO - 13:54:28:    over the design space:
INFO - 13:54:28:       +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:       | Name | Lower bound |        Value         | Upper bound | Type  |
INFO - 13:54:28:       +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:       | x[0] |      -4     | -0.3394642613023262  |      4      | float |
INFO - 13:54:28:       | x[1] |      -4     | -0.3394642613023261  |      4      | float |
INFO - 13:54:28:       | x[2] |      -4     |  -0.339464261302326  |      4      | float |
INFO - 13:54:28:       | t    |     -inf    | -0.04794255057736304 |     inf     | float |
INFO - 13:54:28:       +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:      2%|▏         | 22/1000 [00:00<00:03, 249.05 it/sec, obj=[0.91967277 0.15614049]]
INFO - 13:54:28:      2%|▏         | 23/1000 [00:00<00:03, 256.66 it/sec, obj=[0.84203912 0.33739501]]
INFO - 13:54:28:      2%|▏         | 24/1000 [00:00<00:03, 263.91 it/sec, obj=[0.85527677 0.31046303]]
INFO - 13:54:28:      2%|▎         | 25/1000 [00:00<00:03, 270.63 it/sec, obj=[0.85546004 0.31007996]]
INFO - 13:54:28:      3%|▎         | 26/1000 [00:00<00:03, 277.27 it/sec, obj=[0.85546008 0.31007988]]
INFO - 13:54:28: Optimization result:
INFO - 13:54:28:    Optimizer info:
INFO - 13:54:28:       Status: None
INFO - 13:54:28:       Message: Successive iterates of the objective function are closer than ftol_rel or ftol_abs. GEMSEO Stopped the driver
INFO - 13:54:28:       Number of calls to the objective function by the optimizer: 8
INFO - 13:54:28:    Solution:
INFO - 13:54:28:       The solution is feasible.
INFO - 13:54:28:       Objective: 0.09364292443480814
INFO - 13:54:28:       Standardized constraints:
INFO - 13:54:28:          beta_sub_optim_constraint = [ 1.03119223e-09 -4.66331571e-10]
INFO - 13:54:28:       Design space:
INFO - 13:54:28:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:          | Name | Lower bound |        Value         | Upper bound | Type  |
INFO - 13:54:28:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:          | x[0] |      -4     | -0.2256025149680226  |      4      | float |
INFO - 13:54:28:          | x[1] |      -4     | -0.2256025149680226  |      4      | float |
INFO - 13:54:28:          | x[2] |      -4     | -0.2256025149680226  |      4      | float |
INFO - 13:54:28:          | t    |     -inf    | -0.09364292443480814 |     inf     | float |
INFO - 13:54:28:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28: Solving mNBI sub-problem for beta = [0.33333333 0.66666667]
INFO - 13:54:28: Optimization problem:
INFO - 13:54:28:    minimize -t_extraction
INFO - 13:54:28:    with respect to t, x
INFO - 13:54:28:    subject to constraints:
INFO - 13:54:28:       beta_sub_optim_constraint <= 0.0
INFO - 13:54:28:    over the design space:
INFO - 13:54:28:       +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:       | Name | Lower bound |        Value         | Upper bound | Type  |
INFO - 13:54:28:       +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:       | x[0] |      -4     | -0.2256025149680226  |      4      | float |
INFO - 13:54:28:       | x[1] |      -4     | -0.2256025149680226  |      4      | float |
INFO - 13:54:28:       | x[2] |      -4     | -0.2256025149680226  |      4      | float |
INFO - 13:54:28:       | t    |     -inf    | -0.09364292443480814 |     inf     | float |
INFO - 13:54:28:       +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:      3%|▎         | 27/1000 [00:00<00:04, 241.39 it/sec, obj=[0.85546008 0.31007987]]
INFO - 13:54:28:      3%|▎         | 28/1000 [00:00<00:03, 247.50 it/sec, obj=[0.77161692 0.45984451]]
INFO - 13:54:28:      3%|▎         | 29/1000 [00:00<00:03, 253.11 it/sec, obj=[0.77767797 0.45048948]]
INFO - 13:54:28:      3%|▎         | 30/1000 [00:00<00:03, 258.54 it/sec, obj=[0.77769345 0.45046533]]
INFO - 13:54:28: Optimization result:
INFO - 13:54:28:    Optimizer info:
INFO - 13:54:28:       Status: None
INFO - 13:54:28:       Message: Successive iterates of the design variables are closer than xtol_rel or xtol_abs. GEMSEO Stopped the driver
INFO - 13:54:28:       Number of calls to the objective function by the optimizer: 6
INFO - 13:54:28:    Solution:
INFO - 13:54:28:       The solution is feasible.
INFO - 13:54:28:       Objective: 0.1255364934686558
INFO - 13:54:28:       Standardized constraints:
INFO - 13:54:28:          beta_sub_optim_constraint = [-9.90765803e-12 -5.96217520e-13]
INFO - 13:54:28:       Design space:
INFO - 13:54:28:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28:          | Name | Lower bound |        Value        | Upper bound | Type  |
INFO - 13:54:28:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28:          | x[0] |      -4     | -0.1306276041616624 |      4      | float |
INFO - 13:54:28:          | x[1] |      -4     | -0.1306276041616625 |      4      | float |
INFO - 13:54:28:          | x[2] |      -4     | -0.1306276041616625 |      4      | float |
INFO - 13:54:28:          | t    |     -inf    | -0.1255364934686558 |     inf     | float |
INFO - 13:54:28:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28: Solving mNBI sub-problem for beta = [0.44444444 0.55555556]
INFO - 13:54:28: Optimization problem:
INFO - 13:54:28:    minimize -t_extraction
INFO - 13:54:28:    with respect to t, x
INFO - 13:54:28:    subject to constraints:
INFO - 13:54:28:       beta_sub_optim_constraint <= 0.0
INFO - 13:54:28:    over the design space:
INFO - 13:54:28:       +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28:       | Name | Lower bound |        Value        | Upper bound | Type  |
INFO - 13:54:28:       +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28:       | x[0] |      -4     | -0.1306276041616624 |      4      | float |
INFO - 13:54:28:       | x[1] |      -4     | -0.1306276041616625 |      4      | float |
INFO - 13:54:28:       | x[2] |      -4     | -0.1306276041616625 |      4      | float |
INFO - 13:54:28:       | t    |     -inf    | -0.1255364934686558 |     inf     | float |
INFO - 13:54:28:       +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28:      3%|▎         | 31/1000 [00:00<00:04, 231.07 it/sec, obj=[0.77769345 0.45046533]]
INFO - 13:54:28:      3%|▎         | 32/1000 [00:00<00:04, 235.76 it/sec, obj=[0.68170374 0.57895294]]
INFO - 13:54:28:      3%|▎         | 33/1000 [00:00<00:04, 240.63 it/sec, obj=[0.68463821 0.57556413]]
INFO - 13:54:28:      3%|▎         | 34/1000 [00:00<00:03, 245.41 it/sec, obj=[0.68463912 0.57556308]]
INFO - 13:54:28: Optimization result:
INFO - 13:54:28:    Optimizer info:
INFO - 13:54:28:       Status: None
INFO - 13:54:28:       Message: Successive iterates of the design variables are closer than xtol_rel or xtol_abs. GEMSEO Stopped the driver
INFO - 13:54:28:       Number of calls to the objective function by the optimizer: 6
INFO - 13:54:28:    Solution:
INFO - 13:54:28:       The solution is feasible.
INFO - 13:54:28:       Objective: 0.14185712248151133
INFO - 13:54:28:       Standardized constraints:
INFO - 13:54:28:          beta_sub_optim_constraint = [1.02950981e-12 4.25381952e-13]
INFO - 13:54:28:       Design space:
INFO - 13:54:28:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:          | Name | Lower bound |        Value         | Upper bound | Type  |
INFO - 13:54:28:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:          | x[0] |      -4     | -0.04287486268043029 |      4      | float |
INFO - 13:54:28:          | x[1] |      -4     | -0.04287486268043034 |      4      | float |
INFO - 13:54:28:          | x[2] |      -4     | -0.04287486268043035 |      4      | float |
INFO - 13:54:28:          | t    |     -inf    | -0.1418571224815113  |     inf     | float |
INFO - 13:54:28:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28: Solving mNBI sub-problem for beta = [0.55555556 0.44444444]
INFO - 13:54:28: Optimization problem:
INFO - 13:54:28:    minimize -t_extraction
INFO - 13:54:28:    with respect to t, x
INFO - 13:54:28:    subject to constraints:
INFO - 13:54:28:       beta_sub_optim_constraint <= 0.0
INFO - 13:54:28:    over the design space:
INFO - 13:54:28:       +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:       | Name | Lower bound |        Value         | Upper bound | Type  |
INFO - 13:54:28:       +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:       | x[0] |      -4     | -0.04287486268043029 |      4      | float |
INFO - 13:54:28:       | x[1] |      -4     | -0.04287486268043034 |      4      | float |
INFO - 13:54:28:       | x[2] |      -4     | -0.04287486268043035 |      4      | float |
INFO - 13:54:28:       | t    |     -inf    | -0.1418571224815113  |     inf     | float |
INFO - 13:54:28:       +------+-------------+----------------------+-------------+-------+
INFO - 13:54:28:      4%|▎         | 35/1000 [00:00<00:04, 221.78 it/sec, obj=[0.68463912 0.57556308]]
INFO - 13:54:28:      4%|▎         | 36/1000 [00:00<00:04, 225.34 it/sec, obj=[0.57513103 0.68501143]]
INFO - 13:54:28:      4%|▎         | 37/1000 [00:00<00:04, 229.52 it/sec, obj=[0.5755631 0.6846391]]
INFO - 13:54:28:      4%|▍         | 38/1000 [00:00<00:04, 233.60 it/sec, obj=[0.57556308 0.68463912]]
INFO - 13:54:28: Optimization result:
INFO - 13:54:28:    Optimizer info:
INFO - 13:54:28:       Status: None
INFO - 13:54:28:       Message: Successive iterates of the objective function are closer than ftol_rel or ftol_abs. GEMSEO Stopped the driver
INFO - 13:54:28:       Number of calls to the objective function by the optimizer: 7
INFO - 13:54:28:    Solution:
INFO - 13:54:28:       The solution is feasible.
INFO - 13:54:28:       Objective: 0.14185712248204044
INFO - 13:54:28:       Standardized constraints:
INFO - 13:54:28:          beta_sub_optim_constraint = [1.42996726e-13 3.05810932e-13]
INFO - 13:54:28:       Design space:
INFO - 13:54:28:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28:          | Name | Lower bound |        Value        | Upper bound | Type  |
INFO - 13:54:28:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28:          | x[0] |      -4     | 0.04287486268025626 |      4      | float |
INFO - 13:54:28:          | x[1] |      -4     | 0.04287486268025616 |      4      | float |
INFO - 13:54:28:          | x[2] |      -4     | 0.04287486268025619 |      4      | float |
INFO - 13:54:28:          | t    |     -inf    | -0.1418571224820404 |     inf     | float |
INFO - 13:54:28:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:28: Solving mNBI sub-problem for beta = [0.66666667 0.33333333]
INFO - 13:54:29: Optimization problem:
INFO - 13:54:29:    minimize -t_extraction
INFO - 13:54:29:    with respect to t, x
INFO - 13:54:29:    subject to constraints:
INFO - 13:54:29:       beta_sub_optim_constraint <= 0.0
INFO - 13:54:29:    over the design space:
INFO - 13:54:29:       +------+-------------+---------------------+-------------+-------+
INFO - 13:54:29:       | Name | Lower bound |        Value        | Upper bound | Type  |
INFO - 13:54:29:       +------+-------------+---------------------+-------------+-------+
INFO - 13:54:29:       | x[0] |      -4     | 0.04287486268025626 |      4      | float |
INFO - 13:54:29:       | x[1] |      -4     | 0.04287486268025616 |      4      | float |
INFO - 13:54:29:       | x[2] |      -4     | 0.04287486268025619 |      4      | float |
INFO - 13:54:29:       | t    |     -inf    | -0.1418571224820404 |     inf     | float |
INFO - 13:54:29:       +------+-------------+---------------------+-------------+-------+
INFO - 13:54:29:      4%|▍         | 39/1000 [00:00<00:04, 213.50 it/sec, obj=[0.57556308 0.68463912]]
INFO - 13:54:29:      4%|▍         | 40/1000 [00:00<00:04, 217.08 it/sec, obj=[0.45294727 0.77609783]]
INFO - 13:54:29:      4%|▍         | 41/1000 [00:00<00:04, 220.78 it/sec, obj=[0.45046707 0.77769234]]
INFO - 13:54:29:      4%|▍         | 42/1000 [00:00<00:04, 224.38 it/sec, obj=[0.45046533 0.77769345]]
INFO - 13:54:29: Optimization result:
INFO - 13:54:29:    Optimizer info:
INFO - 13:54:29:       Status: None
INFO - 13:54:29:       Message: Successive iterates of the design variables are closer than xtol_rel or xtol_abs. GEMSEO Stopped the driver
INFO - 13:54:29:       Number of calls to the objective function by the optimizer: 6
INFO - 13:54:29:    Solution:
INFO - 13:54:29:       The solution is feasible.
INFO - 13:54:29:       Objective: 0.1255364934616085
INFO - 13:54:29:       Standardized constraints:
INFO - 13:54:29:          beta_sub_optim_constraint = [1.48561718e-13 9.68516933e-13]
INFO - 13:54:29:       Design space:
INFO - 13:54:29:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:29:          | Name | Lower bound |        Value        | Upper bound | Type  |
INFO - 13:54:29:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:29:          | x[0] |      -4     |  0.1306276041658536 |      4      | float |
INFO - 13:54:29:          | x[1] |      -4     |  0.1306276041658536 |      4      | float |
INFO - 13:54:29:          | x[2] |      -4     |  0.1306276041658536 |      4      | float |
INFO - 13:54:29:          | t    |     -inf    | -0.1255364934616085 |     inf     | float |
INFO - 13:54:29:          +------+-------------+---------------------+-------------+-------+
INFO - 13:54:29: Solving mNBI sub-problem for beta = [0.77777778 0.22222222]
INFO - 13:54:29: Optimization problem:
INFO - 13:54:29:    minimize -t_extraction
INFO - 13:54:29:    with respect to t, x
INFO - 13:54:29:    subject to constraints:
INFO - 13:54:29:       beta_sub_optim_constraint <= 0.0
INFO - 13:54:29:    over the design space:
INFO - 13:54:29:       +------+-------------+---------------------+-------------+-------+
INFO - 13:54:29:       | Name | Lower bound |        Value        | Upper bound | Type  |
INFO - 13:54:29:       +------+-------------+---------------------+-------------+-------+
INFO - 13:54:29:       | x[0] |      -4     |  0.1306276041658536 |      4      | float |
INFO - 13:54:29:       | x[1] |      -4     |  0.1306276041658536 |      4      | float |
INFO - 13:54:29:       | x[2] |      -4     |  0.1306276041658536 |      4      | float |
INFO - 13:54:29:       | t    |     -inf    | -0.1255364934616085 |     inf     | float |
INFO - 13:54:29:       +------+-------------+---------------------+-------------+-------+
INFO - 13:54:29:      4%|▍         | 43/1000 [00:00<00:04, 208.56 it/sec, obj=[0.45046533 0.77769345]]
INFO - 13:54:29:      4%|▍         | 44/1000 [00:00<00:04, 211.84 it/sec, obj=[0.31697497 0.85214023]]
INFO - 13:54:29:      4%|▍         | 45/1000 [00:00<00:04, 215.13 it/sec, obj=[0.31010616 0.85544751]]
INFO - 13:54:29:      5%|▍         | 46/1000 [00:00<00:04, 218.42 it/sec, obj=[0.31007988 0.85546008]]
INFO - 13:54:29: Optimization result:
INFO - 13:54:29:    Optimizer info:
INFO - 13:54:29:       Status: None
INFO - 13:54:29:       Message: Successive iterates of the design variables are closer than xtol_rel or xtol_abs. GEMSEO Stopped the driver
INFO - 13:54:29:       Number of calls to the objective function by the optimizer: 6
INFO - 13:54:29:    Solution:
INFO - 13:54:29:       The solution is feasible.
INFO - 13:54:29:       Objective: 0.09364292499323551
INFO - 13:54:29:       Standardized constraints:
INFO - 13:54:29:          beta_sub_optim_constraint = [ 8.56675841e-13 -2.60819144e-12]
INFO - 13:54:29:       Design space:
INFO - 13:54:29:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:29:          | Name | Lower bound |        Value         | Upper bound | Type  |
INFO - 13:54:29:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:29:          | x[0] |      -4     |  0.225602514270673   |      4      | float |
INFO - 13:54:29:          | x[1] |      -4     |  0.2256025142706731  |      4      | float |
INFO - 13:54:29:          | x[2] |      -4     |  0.225602514270673   |      4      | float |
INFO - 13:54:29:          | t    |     -inf    | -0.09364292499323551 |     inf     | float |
INFO - 13:54:29:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:29: Solving mNBI sub-problem for beta = [0.88888889 0.11111111]
INFO - 13:54:29: Optimization problem:
INFO - 13:54:29:    minimize -t_extraction
INFO - 13:54:29:    with respect to t, x
INFO - 13:54:29:    subject to constraints:
INFO - 13:54:29:       beta_sub_optim_constraint <= 0.0
INFO - 13:54:29:    over the design space:
INFO - 13:54:29:       +------+-------------+----------------------+-------------+-------+
INFO - 13:54:29:       | Name | Lower bound |        Value         | Upper bound | Type  |
INFO - 13:54:29:       +------+-------------+----------------------+-------------+-------+
INFO - 13:54:29:       | x[0] |      -4     |  0.225602514270673   |      4      | float |
INFO - 13:54:29:       | x[1] |      -4     |  0.2256025142706731  |      4      | float |
INFO - 13:54:29:       | x[2] |      -4     |  0.225602514270673   |      4      | float |
INFO - 13:54:29:       | t    |     -inf    | -0.09364292499323551 |     inf     | float |
INFO - 13:54:29:       +------+-------------+----------------------+-------------+-------+
INFO - 13:54:29:      5%|▍         | 47/1000 [00:00<00:04, 204.77 it/sec, obj=[0.31007988 0.85546008]]
INFO - 13:54:29:      5%|▍         | 48/1000 [00:00<00:04, 207.88 it/sec, obj=[0.17146323 0.91399085]]
INFO - 13:54:29:      5%|▍         | 49/1000 [00:00<00:04, 211.04 it/sec, obj=[0.15642562 0.91956815]]
INFO - 13:54:29:      5%|▌         | 50/1000 [00:00<00:04, 214.00 it/sec, obj=[0.1561406  0.91967273]]
INFO - 13:54:29:      5%|▌         | 51/1000 [00:00<00:04, 216.90 it/sec, obj=[0.15614049 0.91967277]]
INFO - 13:54:29: Optimization result:
INFO - 13:54:29:    Optimizer info:
INFO - 13:54:29:       Status: None
INFO - 13:54:29:       Message: Successive iterates of the design variables are closer than xtol_rel or xtol_abs. GEMSEO Stopped the driver
INFO - 13:54:29:       Number of calls to the objective function by the optimizer: 7
INFO - 13:54:29:    Solution:
INFO - 13:54:29:       The solution is feasible.
INFO - 13:54:29:       Objective: 0.04794255057731033
INFO - 13:54:29:       Standardized constraints:
INFO - 13:54:29:          beta_sub_optim_constraint = [-1.83464355e-14  2.24126273e-14]
INFO - 13:54:29:       Design space:
INFO - 13:54:29:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:29:          | Name | Lower bound |        Value         | Upper bound | Type  |
INFO - 13:54:29:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:29:          | x[0] |      -4     |  0.3394642613024756  |      4      | float |
INFO - 13:54:29:          | x[1] |      -4     |  0.3394642613024756  |      4      | float |
INFO - 13:54:29:          | x[2] |      -4     |  0.3394642613024756  |      4      | float |
INFO - 13:54:29:          | t    |     -inf    | -0.04794255057731033 |     inf     | float |
INFO - 13:54:29:          +------+-------------+----------------------+-------------+-------+
INFO - 13:54:29:      5%|▌         | 52/1000 [00:00<00:04, 206.77 it/sec, obj=[0.15614049 0.91967277]]
INFO - 13:54:29: Optimization result:
INFO - 13:54:29:    Optimizer info:
INFO - 13:54:29:       Status: None
INFO - 13:54:29:       Message: None
INFO - 13:54:29:       Number of calls to the objective function by the optimizer: 80
INFO - 13:54:29:    Solution:
INFO - 13:54:29:       Objective: 0.8939534673502061
INFO - 13:54:29:    Pareto efficient solutions:
INFO - 13:54:29:       Pareto optimal points : 42 / 52
INFO - 13:54:29:       Utopia point : [0. 0.]
INFO - 13:54:29:       Compromise solution (closest to utopia) : [[0.63212056 0.63212056]]
INFO - 13:54:29:       Distance from utopia : 0.8939534673502061
INFO - 13:54:29:       Objective values:
INFO - 13:54:29:          +------+----------+----------+----------+
INFO - 13:54:29:          | name |        1 |        2 |        3 |
INFO - 13:54:29:          +------+----------+----------+----------+
INFO - 13:54:29:          |    1 |        0 | 0.981684 | 0.632121 |
INFO - 13:54:29:          |    2 | 0.981684 |        0 | 0.632121 |
INFO - 13:54:29:          +------+----------+----------+----------+
INFO - 13:54:29:       Design space:
INFO - 13:54:29:          +-------+-------------+---------+----------+---+-------------+-------+
INFO - 13:54:29:          |  name | lower_bound |       1 |        2 | 3 | upper_bound |  type |
INFO - 13:54:29:          +-------+-------------+---------+----------+---+-------------+-------+
INFO - 13:54:29:          | x (1) |          -4 | 0.57735 | -0.57735 | 0 |           4 | float |
INFO - 13:54:29:          | x (2) |          -4 | 0.57735 | -0.57735 | 0 |           4 | float |
INFO - 13:54:29:          | x (3) |          -4 | 0.57735 | -0.57735 | 0 |           4 | float |
INFO - 13:54:29:          +-------+-------------+---------+----------+---+-------------+-------+

Display the Pareto front

We can clearly see the effect of the refinement.

execute_post(opt_problem, "ParetoFront", save=False, show=True)
Pareto front
<gemseo.post.pareto_front.ParetoFront object at 0x7f28ec140610>

Total running time of the script: (0 minutes 0.748 seconds)

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