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Python

import numpy as np
from scipy.sparse import csc_matrix
from scipy.optimize._trustregion_constr.qp_subproblem \
import (eqp_kktfact,
projected_cg,
box_intersections,
sphere_intersections,
box_sphere_intersections,
modified_dogleg)
from scipy.optimize._trustregion_constr.projections \
import projections
from numpy.testing import (TestCase, assert_array_almost_equal, assert_equal)
import pytest
class TestEQPDirectFactorization(TestCase):
# From Example 16.2 Nocedal/Wright "Numerical
# Optimization" p.452.
def test_nocedal_example(self):
H = csc_matrix([[6, 2, 1],
[2, 5, 2],
[1, 2, 4]])
A = csc_matrix([[1, 0, 1],
[0, 1, 1]])
c = np.array([-8, -3, -3])
b = -np.array([3, 0])
x, lagrange_multipliers = eqp_kktfact(H, c, A, b)
assert_array_almost_equal(x, [2, -1, 1])
assert_array_almost_equal(lagrange_multipliers, [3, -2])
class TestSphericalBoundariesIntersections(TestCase):
def test_2d_sphere_constraints(self):
# Interior inicial point
ta, tb, intersect = sphere_intersections([0, 0],
[1, 0], 0.5)
assert_array_almost_equal([ta, tb], [0, 0.5])
assert_equal(intersect, True)
# No intersection between line and circle
ta, tb, intersect = sphere_intersections([2, 0],
[0, 1], 1)
assert_equal(intersect, False)
# Outside initial point pointing toward outside the circle
ta, tb, intersect = sphere_intersections([2, 0],
[1, 0], 1)
assert_equal(intersect, False)
# Outside initial point pointing toward inside the circle
ta, tb, intersect = sphere_intersections([2, 0],
[-1, 0], 1.5)
assert_array_almost_equal([ta, tb], [0.5, 1])
assert_equal(intersect, True)
# Initial point on the boundary
ta, tb, intersect = sphere_intersections([2, 0],
[1, 0], 2)
assert_array_almost_equal([ta, tb], [0, 0])
assert_equal(intersect, True)
def test_2d_sphere_constraints_line_intersections(self):
# Interior initial point
ta, tb, intersect = sphere_intersections([0, 0],
[1, 0], 0.5,
entire_line=True)
assert_array_almost_equal([ta, tb], [-0.5, 0.5])
assert_equal(intersect, True)
# No intersection between line and circle
ta, tb, intersect = sphere_intersections([2, 0],
[0, 1], 1,
entire_line=True)
assert_equal(intersect, False)
# Outside initial point pointing toward outside the circle
ta, tb, intersect = sphere_intersections([2, 0],
[1, 0], 1,
entire_line=True)
assert_array_almost_equal([ta, tb], [-3, -1])
assert_equal(intersect, True)
# Outside initial point pointing toward inside the circle
ta, tb, intersect = sphere_intersections([2, 0],
[-1, 0], 1.5,
entire_line=True)
assert_array_almost_equal([ta, tb], [0.5, 3.5])
assert_equal(intersect, True)
# Initial point on the boundary
ta, tb, intersect = sphere_intersections([2, 0],
[1, 0], 2,
entire_line=True)
assert_array_almost_equal([ta, tb], [-4, 0])
assert_equal(intersect, True)
class TestBoxBoundariesIntersections(TestCase):
def test_2d_box_constraints(self):
# Box constraint in the direction of vector d
ta, tb, intersect = box_intersections([2, 0], [0, 2],
[1, 1], [3, 3])
assert_array_almost_equal([ta, tb], [0.5, 1])
assert_equal(intersect, True)
# Negative direction
ta, tb, intersect = box_intersections([2, 0], [0, 2],
[1, -3], [3, -1])
assert_equal(intersect, False)
# Some constraints are absent (set to +/- inf)
ta, tb, intersect = box_intersections([2, 0], [0, 2],
[-np.inf, 1],
[np.inf, np.inf])
assert_array_almost_equal([ta, tb], [0.5, 1])
assert_equal(intersect, True)
# Intersect on the face of the box
ta, tb, intersect = box_intersections([1, 0], [0, 1],
[1, 1], [3, 3])
assert_array_almost_equal([ta, tb], [1, 1])
assert_equal(intersect, True)
# Interior initial point
ta, tb, intersect = box_intersections([0, 0], [4, 4],
[-2, -3], [3, 2])
assert_array_almost_equal([ta, tb], [0, 0.5])
assert_equal(intersect, True)
# No intersection between line and box constraints
ta, tb, intersect = box_intersections([2, 0], [0, 2],
[-3, -3], [-1, -1])
assert_equal(intersect, False)
ta, tb, intersect = box_intersections([2, 0], [0, 2],
[-3, 3], [-1, 1])
assert_equal(intersect, False)
ta, tb, intersect = box_intersections([2, 0], [0, 2],
[-3, -np.inf],
[-1, np.inf])
assert_equal(intersect, False)
ta, tb, intersect = box_intersections([0, 0], [1, 100],
[1, 1], [3, 3])
assert_equal(intersect, False)
ta, tb, intersect = box_intersections([0.99, 0], [0, 2],
[1, 1], [3, 3])
assert_equal(intersect, False)
# Initial point on the boundary
ta, tb, intersect = box_intersections([2, 2], [0, 1],
[-2, -2], [2, 2])
assert_array_almost_equal([ta, tb], [0, 0])
assert_equal(intersect, True)
def test_2d_box_constraints_entire_line(self):
# Box constraint in the direction of vector d
ta, tb, intersect = box_intersections([2, 0], [0, 2],
[1, 1], [3, 3],
entire_line=True)
assert_array_almost_equal([ta, tb], [0.5, 1.5])
assert_equal(intersect, True)
# Negative direction
ta, tb, intersect = box_intersections([2, 0], [0, 2],
[1, -3], [3, -1],
entire_line=True)
assert_array_almost_equal([ta, tb], [-1.5, -0.5])
assert_equal(intersect, True)
# Some constraints are absent (set to +/- inf)
ta, tb, intersect = box_intersections([2, 0], [0, 2],
[-np.inf, 1],
[np.inf, np.inf],
entire_line=True)
assert_array_almost_equal([ta, tb], [0.5, np.inf])
assert_equal(intersect, True)
# Intersect on the face of the box
ta, tb, intersect = box_intersections([1, 0], [0, 1],
[1, 1], [3, 3],
entire_line=True)
assert_array_almost_equal([ta, tb], [1, 3])
assert_equal(intersect, True)
# Interior initial pointoint
ta, tb, intersect = box_intersections([0, 0], [4, 4],
[-2, -3], [3, 2],
entire_line=True)
assert_array_almost_equal([ta, tb], [-0.5, 0.5])
assert_equal(intersect, True)
# No intersection between line and box constraints
ta, tb, intersect = box_intersections([2, 0], [0, 2],
[-3, -3], [-1, -1],
entire_line=True)
assert_equal(intersect, False)
ta, tb, intersect = box_intersections([2, 0], [0, 2],
[-3, 3], [-1, 1],
entire_line=True)
assert_equal(intersect, False)
ta, tb, intersect = box_intersections([2, 0], [0, 2],
[-3, -np.inf],
[-1, np.inf],
entire_line=True)
assert_equal(intersect, False)
ta, tb, intersect = box_intersections([0, 0], [1, 100],
[1, 1], [3, 3],
entire_line=True)
assert_equal(intersect, False)
ta, tb, intersect = box_intersections([0.99, 0], [0, 2],
[1, 1], [3, 3],
entire_line=True)
assert_equal(intersect, False)
# Initial point on the boundary
ta, tb, intersect = box_intersections([2, 2], [0, 1],
[-2, -2], [2, 2],
entire_line=True)
assert_array_almost_equal([ta, tb], [-4, 0])
assert_equal(intersect, True)
def test_3d_box_constraints(self):
# Simple case
ta, tb, intersect = box_intersections([1, 1, 0], [0, 0, 1],
[1, 1, 1], [3, 3, 3])
assert_array_almost_equal([ta, tb], [1, 1])
assert_equal(intersect, True)
# Negative direction
ta, tb, intersect = box_intersections([1, 1, 0], [0, 0, -1],
[1, 1, 1], [3, 3, 3])
assert_equal(intersect, False)
# Interior point
ta, tb, intersect = box_intersections([2, 2, 2], [0, -1, 1],
[1, 1, 1], [3, 3, 3])
assert_array_almost_equal([ta, tb], [0, 1])
assert_equal(intersect, True)
def test_3d_box_constraints_entire_line(self):
# Simple case
ta, tb, intersect = box_intersections([1, 1, 0], [0, 0, 1],
[1, 1, 1], [3, 3, 3],
entire_line=True)
assert_array_almost_equal([ta, tb], [1, 3])
assert_equal(intersect, True)
# Negative direction
ta, tb, intersect = box_intersections([1, 1, 0], [0, 0, -1],
[1, 1, 1], [3, 3, 3],
entire_line=True)
assert_array_almost_equal([ta, tb], [-3, -1])
assert_equal(intersect, True)
# Interior point
ta, tb, intersect = box_intersections([2, 2, 2], [0, -1, 1],
[1, 1, 1], [3, 3, 3],
entire_line=True)
assert_array_almost_equal([ta, tb], [-1, 1])
assert_equal(intersect, True)
class TestBoxSphereBoundariesIntersections(TestCase):
def test_2d_box_constraints(self):
# Both constraints are active
ta, tb, intersect = box_sphere_intersections([1, 1], [-2, 2],
[-1, -2], [1, 2], 2,
entire_line=False)
assert_array_almost_equal([ta, tb], [0, 0.5])
assert_equal(intersect, True)
# None of the constraints are active
ta, tb, intersect = box_sphere_intersections([1, 1], [-1, 1],
[-1, -3], [1, 3], 10,
entire_line=False)
assert_array_almost_equal([ta, tb], [0, 1])
assert_equal(intersect, True)
# Box constraints are active
ta, tb, intersect = box_sphere_intersections([1, 1], [-4, 4],
[-1, -3], [1, 3], 10,
entire_line=False)
assert_array_almost_equal([ta, tb], [0, 0.5])
assert_equal(intersect, True)
# Spherical constraints are active
ta, tb, intersect = box_sphere_intersections([1, 1], [-4, 4],
[-1, -3], [1, 3], 2,
entire_line=False)
assert_array_almost_equal([ta, tb], [0, 0.25])
assert_equal(intersect, True)
# Infeasible problems
ta, tb, intersect = box_sphere_intersections([2, 2], [-4, 4],
[-1, -3], [1, 3], 2,
entire_line=False)
assert_equal(intersect, False)
ta, tb, intersect = box_sphere_intersections([1, 1], [-4, 4],
[2, 4], [2, 4], 2,
entire_line=False)
assert_equal(intersect, False)
def test_2d_box_constraints_entire_line(self):
# Both constraints are active
ta, tb, intersect = box_sphere_intersections([1, 1], [-2, 2],
[-1, -2], [1, 2], 2,
entire_line=True)
assert_array_almost_equal([ta, tb], [0, 0.5])
assert_equal(intersect, True)
# None of the constraints are active
ta, tb, intersect = box_sphere_intersections([1, 1], [-1, 1],
[-1, -3], [1, 3], 10,
entire_line=True)
assert_array_almost_equal([ta, tb], [0, 2])
assert_equal(intersect, True)
# Box constraints are active
ta, tb, intersect = box_sphere_intersections([1, 1], [-4, 4],
[-1, -3], [1, 3], 10,
entire_line=True)
assert_array_almost_equal([ta, tb], [0, 0.5])
assert_equal(intersect, True)
# Spherical constraints are active
ta, tb, intersect = box_sphere_intersections([1, 1], [-4, 4],
[-1, -3], [1, 3], 2,
entire_line=True)
assert_array_almost_equal([ta, tb], [0, 0.25])
assert_equal(intersect, True)
# Infeasible problems
ta, tb, intersect = box_sphere_intersections([2, 2], [-4, 4],
[-1, -3], [1, 3], 2,
entire_line=True)
assert_equal(intersect, False)
ta, tb, intersect = box_sphere_intersections([1, 1], [-4, 4],
[2, 4], [2, 4], 2,
entire_line=True)
assert_equal(intersect, False)
class TestModifiedDogleg(TestCase):
def test_cauchypoint_equalsto_newtonpoint(self):
A = np.array([[1, 8]])
b = np.array([-16])
_, _, Y = projections(A)
newton_point = np.array([0.24615385, 1.96923077])
# Newton point inside boundaries
x = modified_dogleg(A, Y, b, 2, [-np.inf, -np.inf], [np.inf, np.inf])
assert_array_almost_equal(x, newton_point)
# Spherical constraint active
x = modified_dogleg(A, Y, b, 1, [-np.inf, -np.inf], [np.inf, np.inf])
assert_array_almost_equal(x, newton_point/np.linalg.norm(newton_point))
# Box constraints active
x = modified_dogleg(A, Y, b, 2, [-np.inf, -np.inf], [0.1, np.inf])
assert_array_almost_equal(x, (newton_point/newton_point[0]) * 0.1)
def test_3d_example(self):
A = np.array([[1, 8, 1],
[4, 2, 2]])
b = np.array([-16, 2])
Z, LS, Y = projections(A)
newton_point = np.array([-1.37090909, 2.23272727, -0.49090909])
cauchy_point = np.array([0.11165723, 1.73068711, 0.16748585])
origin = np.zeros_like(newton_point)
# newton_point inside boundaries
x = modified_dogleg(A, Y, b, 3, [-np.inf, -np.inf, -np.inf],
[np.inf, np.inf, np.inf])
assert_array_almost_equal(x, newton_point)
# line between cauchy_point and newton_point contains best point
# (spherical constraint is active).
x = modified_dogleg(A, Y, b, 2, [-np.inf, -np.inf, -np.inf],
[np.inf, np.inf, np.inf])
z = cauchy_point
d = newton_point-cauchy_point
t = ((x-z)/(d))
assert_array_almost_equal(t, np.full(3, 0.40807330))
assert_array_almost_equal(np.linalg.norm(x), 2)
# line between cauchy_point and newton_point contains best point
# (box constraint is active).
x = modified_dogleg(A, Y, b, 5, [-1, -np.inf, -np.inf],
[np.inf, np.inf, np.inf])
z = cauchy_point
d = newton_point-cauchy_point
t = ((x-z)/(d))
assert_array_almost_equal(t, np.full(3, 0.7498195))
assert_array_almost_equal(x[0], -1)
# line between origin and cauchy_point contains best point
# (spherical constraint is active).
x = modified_dogleg(A, Y, b, 1, [-np.inf, -np.inf, -np.inf],
[np.inf, np.inf, np.inf])
z = origin
d = cauchy_point
t = ((x-z)/(d))
assert_array_almost_equal(t, np.full(3, 0.573936265))
assert_array_almost_equal(np.linalg.norm(x), 1)
# line between origin and newton_point contains best point
# (box constraint is active).
x = modified_dogleg(A, Y, b, 2, [-np.inf, -np.inf, -np.inf],
[np.inf, 1, np.inf])
z = origin
d = newton_point
t = ((x-z)/(d))
assert_array_almost_equal(t, np.full(3, 0.4478827364))
assert_array_almost_equal(x[1], 1)
class TestProjectCG(TestCase):
# From Example 16.2 Nocedal/Wright "Numerical
# Optimization" p.452.
def test_nocedal_example(self):
H = csc_matrix([[6, 2, 1],
[2, 5, 2],
[1, 2, 4]])
A = csc_matrix([[1, 0, 1],
[0, 1, 1]])
c = np.array([-8, -3, -3])
b = -np.array([3, 0])
Z, _, Y = projections(A)
x, info = projected_cg(H, c, Z, Y, b)
assert_equal(info["stop_cond"], 4)
assert_equal(info["hits_boundary"], False)
assert_array_almost_equal(x, [2, -1, 1])
def test_compare_with_direct_fact(self):
H = csc_matrix([[6, 2, 1, 3],
[2, 5, 2, 4],
[1, 2, 4, 5],
[3, 4, 5, 7]])
A = csc_matrix([[1, 0, 1, 0],
[0, 1, 1, 1]])
c = np.array([-2, -3, -3, 1])
b = -np.array([3, 0])
Z, _, Y = projections(A)
x, info = projected_cg(H, c, Z, Y, b, tol=0)
x_kkt, _ = eqp_kktfact(H, c, A, b)
assert_equal(info["stop_cond"], 1)
assert_equal(info["hits_boundary"], False)
assert_array_almost_equal(x, x_kkt)
def test_trust_region_infeasible(self):
H = csc_matrix([[6, 2, 1, 3],
[2, 5, 2, 4],
[1, 2, 4, 5],
[3, 4, 5, 7]])
A = csc_matrix([[1, 0, 1, 0],
[0, 1, 1, 1]])
c = np.array([-2, -3, -3, 1])
b = -np.array([3, 0])
trust_radius = 1
Z, _, Y = projections(A)
with pytest.raises(ValueError):
projected_cg(H, c, Z, Y, b, trust_radius=trust_radius)
def test_trust_region_barely_feasible(self):
H = csc_matrix([[6, 2, 1, 3],
[2, 5, 2, 4],
[1, 2, 4, 5],
[3, 4, 5, 7]])
A = csc_matrix([[1, 0, 1, 0],
[0, 1, 1, 1]])
c = np.array([-2, -3, -3, 1])
b = -np.array([3, 0])
trust_radius = 2.32379000772445021283
Z, _, Y = projections(A)
x, info = projected_cg(H, c, Z, Y, b,
tol=0,
trust_radius=trust_radius)
assert_equal(info["stop_cond"], 2)
assert_equal(info["hits_boundary"], True)
assert_array_almost_equal(np.linalg.norm(x), trust_radius)
assert_array_almost_equal(x, -Y.dot(b))
def test_hits_boundary(self):
H = csc_matrix([[6, 2, 1, 3],
[2, 5, 2, 4],
[1, 2, 4, 5],
[3, 4, 5, 7]])
A = csc_matrix([[1, 0, 1, 0],
[0, 1, 1, 1]])
c = np.array([-2, -3, -3, 1])
b = -np.array([3, 0])
trust_radius = 3
Z, _, Y = projections(A)
x, info = projected_cg(H, c, Z, Y, b,
tol=0,
trust_radius=trust_radius)
assert_equal(info["stop_cond"], 2)
assert_equal(info["hits_boundary"], True)
assert_array_almost_equal(np.linalg.norm(x), trust_radius)
def test_negative_curvature_unconstrained(self):
H = csc_matrix([[1, 2, 1, 3],
[2, 0, 2, 4],
[1, 2, 0, 2],
[3, 4, 2, 0]])
A = csc_matrix([[1, 0, 1, 0],
[0, 1, 0, 1]])
c = np.array([-2, -3, -3, 1])
b = -np.array([3, 0])
Z, _, Y = projections(A)
with pytest.raises(ValueError):
projected_cg(H, c, Z, Y, b, tol=0)
def test_negative_curvature(self):
H = csc_matrix([[1, 2, 1, 3],
[2, 0, 2, 4],
[1, 2, 0, 2],
[3, 4, 2, 0]])
A = csc_matrix([[1, 0, 1, 0],
[0, 1, 0, 1]])
c = np.array([-2, -3, -3, 1])
b = -np.array([3, 0])
Z, _, Y = projections(A)
trust_radius = 1000
x, info = projected_cg(H, c, Z, Y, b,
tol=0,
trust_radius=trust_radius)
assert_equal(info["stop_cond"], 3)
assert_equal(info["hits_boundary"], True)
assert_array_almost_equal(np.linalg.norm(x), trust_radius)
# The box constraints are inactive at the solution but
# are active during the iterations.
def test_inactive_box_constraints(self):
H = csc_matrix([[6, 2, 1, 3],
[2, 5, 2, 4],
[1, 2, 4, 5],
[3, 4, 5, 7]])
A = csc_matrix([[1, 0, 1, 0],
[0, 1, 1, 1]])
c = np.array([-2, -3, -3, 1])
b = -np.array([3, 0])
Z, _, Y = projections(A)
x, info = projected_cg(H, c, Z, Y, b,
tol=0,
lb=[0.5, -np.inf,
-np.inf, -np.inf],
return_all=True)
x_kkt, _ = eqp_kktfact(H, c, A, b)
assert_equal(info["stop_cond"], 1)
assert_equal(info["hits_boundary"], False)
assert_array_almost_equal(x, x_kkt)
# The box constraints active and the termination is
# by maximum iterations (infeasible iteraction).
def test_active_box_constraints_maximum_iterations_reached(self):
H = csc_matrix([[6, 2, 1, 3],
[2, 5, 2, 4],
[1, 2, 4, 5],
[3, 4, 5, 7]])
A = csc_matrix([[1, 0, 1, 0],
[0, 1, 1, 1]])
c = np.array([-2, -3, -3, 1])
b = -np.array([3, 0])
Z, _, Y = projections(A)
x, info = projected_cg(H, c, Z, Y, b,
tol=0,
lb=[0.8, -np.inf,
-np.inf, -np.inf],
return_all=True)
assert_equal(info["stop_cond"], 1)
assert_equal(info["hits_boundary"], True)
assert_array_almost_equal(A.dot(x), -b)
assert_array_almost_equal(x[0], 0.8)
# The box constraints are active and the termination is
# because it hits boundary (without infeasible iteraction).
def test_active_box_constraints_hits_boundaries(self):
H = csc_matrix([[6, 2, 1, 3],
[2, 5, 2, 4],
[1, 2, 4, 5],
[3, 4, 5, 7]])
A = csc_matrix([[1, 0, 1, 0],
[0, 1, 1, 1]])
c = np.array([-2, -3, -3, 1])
b = -np.array([3, 0])
trust_radius = 3
Z, _, Y = projections(A)
x, info = projected_cg(H, c, Z, Y, b,
tol=0,
ub=[np.inf, np.inf, 1.6, np.inf],
trust_radius=trust_radius,
return_all=True)
assert_equal(info["stop_cond"], 2)
assert_equal(info["hits_boundary"], True)
assert_array_almost_equal(x[2], 1.6)
# The box constraints are active and the termination is
# because it hits boundary (infeasible iteraction).
def test_active_box_constraints_hits_boundaries_infeasible_iter(self):
H = csc_matrix([[6, 2, 1, 3],
[2, 5, 2, 4],
[1, 2, 4, 5],
[3, 4, 5, 7]])
A = csc_matrix([[1, 0, 1, 0],
[0, 1, 1, 1]])
c = np.array([-2, -3, -3, 1])
b = -np.array([3, 0])
trust_radius = 4
Z, _, Y = projections(A)
x, info = projected_cg(H, c, Z, Y, b,
tol=0,
ub=[np.inf, 0.1, np.inf, np.inf],
trust_radius=trust_radius,
return_all=True)
assert_equal(info["stop_cond"], 2)
assert_equal(info["hits_boundary"], True)
assert_array_almost_equal(x[1], 0.1)
# The box constraints are active and the termination is
# because it hits boundary (no infeasible iteraction).
def test_active_box_constraints_negative_curvature(self):
H = csc_matrix([[1, 2, 1, 3],
[2, 0, 2, 4],
[1, 2, 0, 2],
[3, 4, 2, 0]])
A = csc_matrix([[1, 0, 1, 0],
[0, 1, 0, 1]])
c = np.array([-2, -3, -3, 1])
b = -np.array([3, 0])
Z, _, Y = projections(A)
trust_radius = 1000
x, info = projected_cg(H, c, Z, Y, b,
tol=0,
ub=[np.inf, np.inf, 100, np.inf],
trust_radius=trust_radius)
assert_equal(info["stop_cond"], 3)
assert_equal(info["hits_boundary"], True)
assert_array_almost_equal(x[2], 100)