#!/usr/bin/env python
"""
An optimization problem with mixed discrete input variables "4d soo".

min f(x1,x2,disc_b,logic)
where
x1 in [-5,5], x2 in [-3,3], disc_b in {True,False}, logic in {True,False}

4D function with a mixed decision space (two numeric, one discrete,
and one logical parameter)

In the original problem, we have disc_b in {"a","b"}.

Reference
Ported from R to Python.
Package ‘smoof’, August 14, 2017
Single and Multi-Objective Optimization Test Functions
Jakob Bossek
"""

import openturns as ot
import openturns.testing as ott


def fourdsoo(x):
    x1, x2, disc_b, logic = x
    # minimum : f([-5,-3,1,1]) = -18
    if round(disc_b) == 0.0:
        result = x1**2 + x2**2 + 10 * round(logic)
    else:
        result = x1 + x2 - 10 * round(logic)
    return [result]


# Create the objective function
objectiveFun = ot.PythonFunction(4, 1, fourdsoo)

x = [-5, -3, 1, 1]

print(f"f(x)={objectiveFun(x)}")

# Define bounds
bounds = ot.Interval([-5.0, -3.0, 0.0, 0.0], [5.0, 3.0, 1, 1])

# Define variable types
varTypes = [
    ot.OptimizationProblemImplementation.CONTINUOUS,
    ot.OptimizationProblemImplementation.CONTINUOUS,
    ot.OptimizationProblemImplementation.BINARY,
    ot.OptimizationProblemImplementation.INTEGER,
]

# Define problem
problem = ot.OptimizationProblem(objectiveFun)
problem.setVariablesType(varTypes)
problem.setBounds(bounds)
problem.setMinimization(True)

x0 = [0.0] * 4
algo = ot.Bonmin(problem)
algo.setStartingPoint(x0)
algo.setMaximumCallsNumber(10000)
algo.setMaximumIterationNumber(1000)

for name in ot.Bonmin.GetAlgorithmNames():
    if name in ["B-OA", "B-QG", "B-Ecp"]:
        continue
    print(f"-- {name} algorithm...")
    algo.setAlgorithmName(name)
    algo.run()
    result = algo.getResult()
    x_star = result.getOptimalPoint()
    print(f"x*={x_star}")
    y_star = result.getOptimalValue()
    neval = result.getCallsNumber()
    print(f"f(x*)={y_star} neval={neval}")
    ott.assert_almost_equal(x_star, [-5, -3, 1, 1], 5e-4)