def test_basinhopping():
def func(x):
return np.cos(14.5 * x - 0.3) + (x + 0.2) * x
x0 = [1.]
np.random.seed(555)
res = basinhopping(func, x0, minimizer_kwargs={"method": "BFGS"}, niter=200)
np.random.seed(555)
x, = parameters('x')
fit = BasinHopping(func, [x], local_minimizer=BFGS)
fit_result = fit.execute(niter=200)
# fit_result = fit.execute(minimizer_kwargs={"method": "BFGS"}, niter=200)
assert res.x == fit_result.value(x)
assert res.fun == fit_result.objective_value
def test_basinhopping_large():
"""
Test the basinhopping method of scipy.minimize. This is based of scipy's docs
as found here: https://docs.scipy.org/doc/scipy-0.13.0/reference/generated/scipy.optimize.anneal.html
"""
def f1(z, *params):
x, y = z
a, b, c, d, e, f, g, h, i, j, k, l, scale = params
return (a * x ** 2 + b * x * y + c * y ** 2 + d * x + e * y + f)
def f2(z, *params):
x, y = z
a, b, c, d, e, f, g, h, i, j, k, l, scale = params
return (-g * np.exp(-((x - h) ** 2 + (y - i) ** 2) / scale))
def f3(z, *params):
x, y = z
a, b, c, d, e, f, g, h, i, j, k, l, scale = params
return (-j * np.exp(-((x - k) ** 2 + (y - l) ** 2) / scale))
def func(z, *params):
x, y = z
a, b, c, d, e, f, g, h, i, j, k, l, scale = params
return f1(z, *params) + f2(z, *params) + f3(z, *params)
def f_symfit(x1, x2, params):
z = [x1, x2]
return func(z, *params)
params = (2, 3, 7, 8, 9, 10, 44, -1, 2, 26, 1, -2, 0.5)
x0 = np.array([2., 2.])
np.random.seed(555)
res = basinhopping(func, x0, minimizer_kwargs={'args': params})
np.random.seed(555)
x1, x2 = parameters('x1, x2', value=x0)
fit = BasinHopping(partial(f_symfit, params=params), [x1, x2])
fit_result = fit.execute()
assert res.x[0] == fit_result.value(x1)
assert res.x[1] == fit_result.value(x2)
assert res.fun == fit_result.objective_value
def test_basinhopping_2d():
def func2d(x):
f = np.cos(14.5 * x[0] - 0.3) + (x[1] + 0.2) * x[1] + (x[0] + 0.2) * x[0]
df = np.zeros(2)
df[0] = -14.5 * np.sin(14.5 * x[0] - 0.3) + 2. * x[0] + 0.2
df[1] = 2. * x[1] + 0.2
return f, df
def func2d_symfit(x1, x2):
f = np.cos(14.5 * x1 - 0.3) + (x2 + 0.2) * x2 + (x1 + 0.2) * x1
return f
def jac2d_symfit(x1, x2):
df = np.zeros(2)
df[0] = -14.5 * np.sin(14.5 * x1 - 0.3) + 2. * x1 + 0.2
df[1] = 2. * x2 + 0.2
return df
np.random.seed(555)
minimizer_kwargs = {'method': 'BFGS', 'jac': True}
x0 = [1.0, 1.0]
res = basinhopping(func2d, x0, minimizer_kwargs=minimizer_kwargs, niter=200)
np.random.seed(555)
x1, x2 = parameters('x1, x2', value=x0)
with pytest.raises(TypeError):
fit = BasinHopping(
func2d_symfit, [x1, x2],
local_minimizer=NelderMead(func2d_symfit, [x1, x2],
jacobian=jac2d_symfit)
)
fit = BasinHopping(
func2d_symfit, [x1, x2],
local_minimizer=BFGS(func2d_symfit, [x1, x2], jacobian=jac2d_symfit)
)
fit_result = fit.execute(niter=200)
assert isinstance(fit.local_minimizer.jacobian, MinimizeModel)
assert isinstance(fit.local_minimizer.jacobian.model, CallableNumericalModel)
assert res.x[0] == fit_result.value(x1)
assert res.x[1] == fit_result.value(x2)
assert res.fun == fit_result.objective_value
# Now compare with the symbolic equivalent
np.random.seed(555)
model = cos(14.5 * x1 - 0.3) + (x2 + 0.2) * x2 + (x1 + 0.2) * x1
fit = Fit(model, minimizer=BasinHopping)
fit_result = fit.execute()
assert res.x[0] == fit_result.value(x1)
assert res.x[1] == fit_result.value(x2)
assert res.fun == fit_result.objective_value
assert isinstance(fit.minimizer.local_minimizer, BFGS)
# Impose constrains
np.random.seed(555)
model = cos(14.5 * x1 - 0.3) + (x2 + 0.2) * x2 + (x1 + 0.2) * x1
fit = Fit(model, minimizer=BasinHopping, constraints=[Eq(x1, x2)])
fit_result = fit.execute()
assert fit_result.value(x1) == fit_result.value(x2)
assert isinstance(fit.minimizer.local_minimizer, SLSQP)
# Impose bounds
np.random.seed(555)
x1.min = 0.0
model = cos(14.5 * x1 - 0.3) + (x2 + 0.2) * x2 + (x1 + 0.2) * x1
fit = Fit(model, minimizer=BasinHopping)
fit_result = fit.execute()
assert fit_result.value(x1) >= x1.min
assert isinstance(fit.minimizer.local_minimizer, LBFGSB)