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324 lines
12 KiB
Python
324 lines
12 KiB
Python
# Dual annealing unit tests implementation.
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# Copyright (c) 2018 Sylvain Gubian <sylvain.gubian@pmi.com>,
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# Yang Xiang <yang.xiang@pmi.com>
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# Author: Sylvain Gubian, PMP S.A.
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"""
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Unit tests for the dual annealing global optimizer
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"""
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from scipy.optimize import dual_annealing
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from scipy.optimize._dual_annealing import EnergyState
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from scipy.optimize._dual_annealing import LocalSearchWrapper
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from scipy.optimize._dual_annealing import ObjectiveFunWrapper
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from scipy.optimize._dual_annealing import StrategyChain
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from scipy.optimize._dual_annealing import VisitingDistribution
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from scipy.optimize import rosen, rosen_der
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import pytest
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import numpy as np
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from numpy.testing import assert_equal, assert_allclose, assert_array_less
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from pytest import raises as assert_raises
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from scipy._lib._util import check_random_state
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from scipy._lib._pep440 import Version
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class TestDualAnnealing:
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def setup_method(self):
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# A function that returns always infinity for initialization tests
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self.weirdfunc = lambda x: np.inf
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# 2-D bounds for testing function
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self.ld_bounds = [(-5.12, 5.12)] * 2
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# 4-D bounds for testing function
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self.hd_bounds = self.ld_bounds * 4
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# Number of values to be generated for testing visit function
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self.nbtestvalues = 5000
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self.high_temperature = 5230
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self.low_temperature = 0.1
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self.qv = 2.62
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self.seed = 1234
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self.rs = check_random_state(self.seed)
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self.nb_fun_call = 0
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self.ngev = 0
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def callback(self, x, f, context):
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# For testing callback mechanism. Should stop for e <= 1 as
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# the callback function returns True
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if f <= 1.0:
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return True
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def func(self, x, args=()):
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# Using Rastrigin function for performing tests
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if args:
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shift = args
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else:
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shift = 0
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y = np.sum((x - shift) ** 2 - 10 * np.cos(2 * np.pi * (
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x - shift))) + 10 * np.size(x) + shift
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self.nb_fun_call += 1
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return y
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def rosen_der_wrapper(self, x, args=()):
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self.ngev += 1
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return rosen_der(x, *args)
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def test_visiting_stepping(self):
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lu = list(zip(*self.ld_bounds))
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lower = np.array(lu[0])
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upper = np.array(lu[1])
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dim = lower.size
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vd = VisitingDistribution(lower, upper, self.qv, self.rs)
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values = np.zeros(dim)
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x_step_low = vd.visiting(values, 0, self.high_temperature)
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# Make sure that only the first component is changed
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assert_equal(np.not_equal(x_step_low, 0), True)
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values = np.zeros(dim)
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x_step_high = vd.visiting(values, dim, self.high_temperature)
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# Make sure that component other than at dim has changed
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assert_equal(np.not_equal(x_step_high[0], 0), True)
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def test_visiting_dist_high_temperature(self):
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lu = list(zip(*self.ld_bounds))
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lower = np.array(lu[0])
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upper = np.array(lu[1])
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vd = VisitingDistribution(lower, upper, self.qv, self.rs)
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# values = np.zeros(self.nbtestvalues)
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# for i in np.arange(self.nbtestvalues):
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# values[i] = vd.visit_fn(self.high_temperature)
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values = vd.visit_fn(self.high_temperature, self.nbtestvalues)
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# Visiting distribution is a distorted version of Cauchy-Lorentz
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# distribution, and as no 1st and higher moments (no mean defined,
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# no variance defined).
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# Check that big tails values are generated
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assert_array_less(np.min(values), 1e-10)
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assert_array_less(1e+10, np.max(values))
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def test_reset(self):
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owf = ObjectiveFunWrapper(self.weirdfunc)
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lu = list(zip(*self.ld_bounds))
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lower = np.array(lu[0])
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upper = np.array(lu[1])
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es = EnergyState(lower, upper)
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assert_raises(ValueError, es.reset, owf, check_random_state(None))
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def test_low_dim(self):
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ret = dual_annealing(
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self.func, self.ld_bounds, seed=self.seed)
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assert_allclose(ret.fun, 0., atol=1e-12)
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assert ret.success
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def test_high_dim(self):
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ret = dual_annealing(self.func, self.hd_bounds, seed=self.seed)
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assert_allclose(ret.fun, 0., atol=1e-12)
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assert ret.success
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def test_low_dim_no_ls(self):
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ret = dual_annealing(self.func, self.ld_bounds,
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no_local_search=True, seed=self.seed)
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assert_allclose(ret.fun, 0., atol=1e-4)
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def test_high_dim_no_ls(self):
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ret = dual_annealing(self.func, self.hd_bounds,
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no_local_search=True, seed=self.seed)
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assert_allclose(ret.fun, 0., atol=1e-4)
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def test_nb_fun_call(self):
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ret = dual_annealing(self.func, self.ld_bounds, seed=self.seed)
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assert_equal(self.nb_fun_call, ret.nfev)
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def test_nb_fun_call_no_ls(self):
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ret = dual_annealing(self.func, self.ld_bounds,
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no_local_search=True, seed=self.seed)
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assert_equal(self.nb_fun_call, ret.nfev)
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def test_max_reinit(self):
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assert_raises(ValueError, dual_annealing, self.weirdfunc,
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self.ld_bounds)
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def test_reproduce(self):
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res1 = dual_annealing(self.func, self.ld_bounds, seed=self.seed)
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res2 = dual_annealing(self.func, self.ld_bounds, seed=self.seed)
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res3 = dual_annealing(self.func, self.ld_bounds, seed=self.seed)
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# If we have reproducible results, x components found has to
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# be exactly the same, which is not the case with no seeding
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assert_equal(res1.x, res2.x)
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assert_equal(res1.x, res3.x)
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@pytest.mark.skipif(Version(np.__version__) < Version('1.17'),
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reason='Generator not available for numpy, < 1.17')
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def test_rand_gen(self):
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# check that np.random.Generator can be used (numpy >= 1.17)
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# obtain a np.random.Generator object
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rng = np.random.default_rng(1)
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res1 = dual_annealing(self.func, self.ld_bounds, seed=rng)
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# seed again
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rng = np.random.default_rng(1)
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res2 = dual_annealing(self.func, self.ld_bounds, seed=rng)
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# If we have reproducible results, x components found has to
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# be exactly the same, which is not the case with no seeding
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assert_equal(res1.x, res2.x)
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def test_bounds_integrity(self):
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wrong_bounds = [(-5.12, 5.12), (1, 0), (5.12, 5.12)]
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assert_raises(ValueError, dual_annealing, self.func,
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wrong_bounds)
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def test_bound_validity(self):
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invalid_bounds = [(-5, 5), (-np.inf, 0), (-5, 5)]
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assert_raises(ValueError, dual_annealing, self.func,
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invalid_bounds)
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invalid_bounds = [(-5, 5), (0, np.inf), (-5, 5)]
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assert_raises(ValueError, dual_annealing, self.func,
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invalid_bounds)
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invalid_bounds = [(-5, 5), (0, np.nan), (-5, 5)]
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assert_raises(ValueError, dual_annealing, self.func,
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invalid_bounds)
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def test_local_search_option_bounds(self):
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func = lambda x: np.sum((x-5) * (x-1))
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bounds = list(zip([-6, -5], [6, 5]))
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# Test bounds can be passed (see gh-10831)
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dual_annealing(
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func,
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bounds=bounds,
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local_search_options={"method": "SLSQP", "bounds": bounds})
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with np.testing.suppress_warnings() as sup:
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sup.record(RuntimeWarning, "Method CG cannot handle ")
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dual_annealing(
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func,
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bounds=bounds,
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local_search_options={"method": "CG", "bounds": bounds})
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# Verify warning happened for Method cannot handle bounds.
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assert sup.log
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def test_max_fun_ls(self):
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ret = dual_annealing(self.func, self.ld_bounds, maxfun=100,
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seed=self.seed)
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ls_max_iter = min(max(
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len(self.ld_bounds) * LocalSearchWrapper.LS_MAXITER_RATIO,
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LocalSearchWrapper.LS_MAXITER_MIN),
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LocalSearchWrapper.LS_MAXITER_MAX)
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assert ret.nfev <= 100 + ls_max_iter
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assert not ret.success
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def test_max_fun_no_ls(self):
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ret = dual_annealing(self.func, self.ld_bounds,
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no_local_search=True, maxfun=500, seed=self.seed)
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assert ret.nfev <= 500
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assert not ret.success
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def test_maxiter(self):
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ret = dual_annealing(self.func, self.ld_bounds, maxiter=700,
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seed=self.seed)
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assert ret.nit <= 700
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# Testing that args are passed correctly for dual_annealing
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def test_fun_args_ls(self):
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ret = dual_annealing(self.func, self.ld_bounds,
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args=((3.14159,)), seed=self.seed)
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assert_allclose(ret.fun, 3.14159, atol=1e-6)
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# Testing that args are passed correctly for pure simulated annealing
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def test_fun_args_no_ls(self):
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ret = dual_annealing(self.func, self.ld_bounds,
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args=((3.14159, )), no_local_search=True,
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seed=self.seed)
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assert_allclose(ret.fun, 3.14159, atol=1e-4)
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def test_callback_stop(self):
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# Testing that callback make the algorithm stop for
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# fun value <= 1.0 (see callback method)
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ret = dual_annealing(self.func, self.ld_bounds,
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callback=self.callback, seed=self.seed)
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assert ret.fun <= 1.0
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assert 'stop early' in ret.message[0]
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assert not ret.success
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@pytest.mark.parametrize('method, atol', [
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('Nelder-Mead', 2e-5),
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('COBYLA', 1e-5),
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('Powell', 1e-8),
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('CG', 1e-8),
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('BFGS', 1e-8),
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('TNC', 1e-8),
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('SLSQP', 2e-7),
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])
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def test_multi_ls_minimizer(self, method, atol):
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ret = dual_annealing(self.func, self.ld_bounds,
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local_search_options=dict(method=method),
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seed=self.seed)
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assert_allclose(ret.fun, 0., atol=atol)
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def test_wrong_restart_temp(self):
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assert_raises(ValueError, dual_annealing, self.func,
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self.ld_bounds, restart_temp_ratio=1)
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assert_raises(ValueError, dual_annealing, self.func,
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self.ld_bounds, restart_temp_ratio=0)
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def test_gradient_gnev(self):
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minimizer_opts = {
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'jac': self.rosen_der_wrapper,
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}
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ret = dual_annealing(rosen, self.ld_bounds,
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local_search_options=minimizer_opts,
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seed=self.seed)
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assert ret.njev == self.ngev
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def test_from_docstring(self):
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func = lambda x: np.sum(x * x - 10 * np.cos(2 * np.pi * x)) + 10 * np.size(x)
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lw = [-5.12] * 10
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up = [5.12] * 10
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ret = dual_annealing(func, bounds=list(zip(lw, up)), seed=1234)
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assert_allclose(ret.x,
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[-4.26437714e-09, -3.91699361e-09, -1.86149218e-09,
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-3.97165720e-09, -6.29151648e-09, -6.53145322e-09,
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-3.93616815e-09, -6.55623025e-09, -6.05775280e-09,
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-5.00668935e-09], atol=4e-8)
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assert_allclose(ret.fun, 0.000000, atol=5e-13)
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@pytest.mark.parametrize('new_e, temp_step, accepted, accept_rate', [
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(0, 100, 1000, 1.0097587941791923),
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(0, 2, 1000, 1.2599210498948732),
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(10, 100, 878, 0.8786035869128718),
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(10, 60, 695, 0.6812920690579612),
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(2, 100, 990, 0.9897404249173424),
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])
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def test_accept_reject_probabilistic(
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self, new_e, temp_step, accepted, accept_rate):
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# Test accepts unconditionally with e < current_energy and
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# probabilistically with e > current_energy
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rs = check_random_state(123)
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count_accepted = 0
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iterations = 1000
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accept_param = -5
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current_energy = 1
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for _ in range(iterations):
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energy_state = EnergyState(lower=None, upper=None)
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# Set energy state with current_energy, any location.
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energy_state.update_current(current_energy, [0])
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chain = StrategyChain(
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accept_param, None, None, None, rs, energy_state)
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# Normally this is set in run()
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chain.temperature_step = temp_step
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# Check if update is accepted.
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chain.accept_reject(j=1, e=new_e, x_visit=[2])
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if energy_state.current_energy == new_e:
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count_accepted += 1
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assert count_accepted == accepted
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# Check accept rate
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pqv = 1 - (1 - accept_param) * (new_e - current_energy) / temp_step
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rate = 0 if pqv <= 0 else np.exp(np.log(pqv) / (1 - accept_param))
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assert_allclose(rate, accept_rate)
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