def test_l1prox():
'''
this test verifies that the l1 prox in lagrange form can be solved
by a primal/dual specification
obviously, we don't to solve the l1 prox this way,
but it verifies that specification is working correctly
'''
l1 = rr.l1norm(4, lagrange=0.3)
ww = np.random.standard_normal(4)*3
ab = l1.proximal(rr.identity_quadratic(0.5, ww, 0,0))
l1c = copy(l1)
l1c.quadratic = rr.identity_quadratic(0.5, ww, None, 0.)
a = rr.simple_problem.nonsmooth(l1c)
solver = rr.FISTA(a)
solver.fit(tol=1.e-10)
ad = a.coefs
l1c = copy(l1)
l1c.quadratic = rr.identity_quadratic(0.5, ww, None, 0.)
a = rr.dual_problem.fromprimal(l1c)
solver = rr.FISTA(a)
solver.fit(tol=1.0e-14)
ac = a.primal
np.testing.assert_allclose(ac, ab, rtol=1.0e-4)
np.testing.assert_allclose(ac, ad, rtol=1.0e-4)
def test_multinomial_vs_logistic():
"""
Test that multinomial regression with two categories is the same as logistic regression
"""
n = 500
p = 10
J = 2
X = np.random.standard_normal(n*p).reshape((n,p))
counts = np.random.randint(0,10,n*J).reshape((n,J)) + 2
mult_x = rr.linear_transform(X, input_shape=(p,J-1))
loss = rr.multinomial_deviance.linear(mult_x, counts=counts)
problem = rr.container(loss)
solver = rr.FISTA(problem)
solver.fit(debug=False, tol=1e-10)
coefs1 = solver.composite.coefs
loss = rr.logistic_deviance.linear(X, successes=counts[:,0], trials = np.sum(counts, axis=1))
problem = rr.container(loss)
solver = rr.FISTA(problem)
solver.fit(debug=False, tol=1e-10)
coefs2 = solver.composite.coefs
loss = rr.logistic_deviance.linear(X, successes=counts[:,1], trials = np.sum(counts, axis=1))
problem = rr.container(loss)
solver = rr.FISTA(problem)
solver.fit(debug=False, tol=1e-10)
coefs3 = solver.composite.coefs
npt.assert_equal(coefs1.shape,(p,J-1))
npt.assert_array_almost_equal(coefs1.flatten(), coefs2.flatten(), 5)
npt.assert_array_almost_equal(coefs1.flatten(), -coefs3.flatten(), 5)
def test_separable(self):
tests = []
atom, q, prox_center, L = self.atom, self.q, self.prox_center, self.L
loss = self.loss
problem = rr.separable_problem.singleton(atom, loss)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-12,
coef_stop=self.coef_stop,
FISTA=self.FISTA,
min_its=100)
tests.append((atom.proximal(q), solver.composite.coefs,
'solving atom prox with separable_atom.singleton \n%s ' %
str(self)))
d = atom.conjugate
problem = rr.separable_problem.singleton(d, loss)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-12,
coef_stop=self.coef_stop,
FISTA=self.FISTA,
min_its=100)
tests.append(
(d.proximal(q), solver.composite.coefs,
'solving dual atom prox with separable_atom.singleton \n%s ' %
str(self)))
if not self.interactive:
for test in tests:
yield (all_close, ) + test + (self, )
else:
for test in tests:
yield all_close(*((test + (self, ))))
def test_group_lasso_separable():
"""
This test verifies that the specification of a separable
penalty yields the same results as having two linear_atoms
with selector matrices. The penalty here is a group_lasso, i.e. l2
penalty.
"""
X = np.random.standard_normal((100,20))
Y = np.random.standard_normal((100,)) + np.dot(X, np.random.standard_normal(20))
penalty1 = rr.l2norm(10, lagrange=.2)
penalty2 = rr.l2norm(10, lagrange=.2)
penalty = rr.separable((20,), [penalty1, penalty2], [slice(0,10), slice(10,20)])
# solve using separable
loss = rr.quadratic_loss.affine(X, -Y, coef=0.5)
problem = rr.separable_problem.fromatom(penalty, loss)
solver = rr.FISTA(problem)
solver.fit(min_its=200, tol=1.0e-12)
coefs = solver.composite.coefs
# solve using the selectors
penalty_s = [rr.linear_atom(p, rr.selector(g, (20,))) for p, g in
zip(penalty.atoms, penalty.groups)]
problem_s = rr.container(loss, *penalty_s)
solver_s = rr.FISTA(problem_s)
solver_s.fit(min_its=200, tol=1.0e-12)
coefs_s = solver_s.composite.coefs
np.testing.assert_almost_equal(coefs, coefs_s)
def test_nonnegative_positive_part(debug=False):
"""
This test verifies that using nonnegative constraint
with a linear term, with some unpenalized terms yields the same result
as using separable with constrained_positive_part and nonnegative
"""
import numpy as np
import regreg.api as rr
import regreg.atoms as rra
# N - number of data points
# P - number of columns in design == number of betas
N, P = 40, 30
# an arbitrary positive offset for data and design
offset = 2
# data
Y = np.random.normal(size=(N, )) + offset
# design - with ones as last column
X = np.ones((N, P))
X[:, :-1] = np.random.normal(size=(N, P - 1)) + offset
# coef for loss
coef = 0.5
# lagrange for penalty
lagrange = .1
# Loss function (squared difference between fitted and actual data)
loss = rr.quadratic_loss.affine(X, -Y, coef=coef)
# Penalty using nonnegative, leave the last 5 unpenalized but
# nonnegative
weights = np.ones(P) * lagrange
weights[-5:] = 0
linq = rr.identity_quadratic(0, 0, weights, 0)
penalty = rr.nonnegative(P, quadratic=linq)
# Solution
composite_form = rr.separable_problem.singleton(penalty, loss)
solver = rr.FISTA(composite_form)
solver.debug = debug
solver.fit(tol=1.0e-12, min_its=200)
coefs = solver.composite.coefs
# using the separable penalty, only penalize the first
# 25 coefficients with constrained_positive_part
penalties_s = [
rr.constrained_positive_part(25, lagrange=lagrange),
rr.nonnegative(5)
]
groups_s = [slice(0, 25), slice(25, 30)]
penalty_s = rr.separable((P, ), penalties_s, groups_s)
composite_form_s = rr.separable_problem.singleton(penalty_s, loss)
solver_s = rr.FISTA(composite_form_s)
solver_s.debug = debug
solver_s.fit(tol=1.0e-12, min_its=200)
coefs_s = solver_s.composite.coefs
nt.assert_true(
np.linalg.norm(coefs - coefs_s) / np.linalg.norm(coefs) < 1.0e-02)
def test_lasso_dual():
"""
Check that the solution of the lasso signal approximator dual composite is soft-thresholding
"""
l1 = .1
sparsity = R.l1norm(10, lagrange=l1)
x = np.arange(10) - 5
loss = R.quadratic.shift(-x, coef=0.5)
pen = R.simple_problem(loss, sparsity)
solver = R.FISTA(pen)
pen.lipschitz = 1
solver.fit(backtrack=False)
soln = solver.composite.coefs
st = np.maximum(np.fabs(x)-l1,0) * np.sign(x)
np.testing.assert_almost_equal(soln,st, decimal=3)
pen = R.simple_problem(loss, sparsity)
solver = R.FISTA(pen)
solver.fit(monotonicity_restart=False)
soln = solver.composite.coefs
st = np.maximum(np.fabs(x)-l1,0) * np.sign(x)
np.testing.assert_almost_equal(soln,st, decimal=3)
pen = R.container(loss, sparsity)
solver = R.FISTA(pen)
solver.fit()
soln = solver.composite.coefs
np.testing.assert_almost_equal(soln,st, decimal=3)
def test_l1prox_bound():
'''
this test verifies that the l1 prox in bound form can be solved
by a primal/dual specification
obviously, we don't to solve the l1 prox this way,
but it verifies that specification is working correctly
'''
l1 = rr.l1norm(4, bound=2.)
ww = np.random.standard_normal(4) * 2
ab = l1.proximal(rr.identity_quadratic(0.5, ww, 0, 0))
l1c = copy(l1)
l1c.quadratic = rr.identity_quadratic(0.5, ww, None, 0.)
a = rr.simple_problem.nonsmooth(l1c)
solver = rr.FISTA(a)
solver.fit(min_its=100)
l1c = copy(l1)
l1c.quadratic = rr.identity_quadratic(0.5, ww, None, 0.)
a = rr.dual_problem.fromprimal(l1c)
solver = rr.FISTA(a)
solver.fit(min_its=100)
ac = a.primal
np.testing.assert_allclose(ac + 0.1, ab + 0.1, rtol=1.e-4)
def test_lasso():
'''
this test verifies that the l1 prox can be solved
by a primal/dual specification
obviously, we don't to solve the l1 prox this way,
but it verifies that specification is working correctly
'''
l1 = rr.l1norm(4, lagrange=2.)
l11 = rr.l1norm(4, lagrange=1.)
l12 = rr.l1norm(4, lagrange=1.)
X = np.random.standard_normal((10, 4))
Y = np.random.standard_normal(10) + 3
loss = rr.quadratic.affine(X, -Y)
p1 = rr.container(l11, loss, l12)
solver1 = rr.FISTA(p1)
solver1.fit(tol=1.0e-12, min_its=500)
p2 = rr.separable_problem.singleton(l1, loss)
solver2 = rr.FISTA(p2)
solver2.fit(tol=1.0e-12)
f = p2.objective
ans = scipy.optimize.fmin_powell(f, np.zeros(4), ftol=1.0e-12)
print(f(solver2.composite.coefs), f(ans))
print(f(solver1.composite.coefs), f(ans))
yield all_close, ans, solver2.composite.coefs, 'singleton solver', None
yield all_close, solver1.composite.coefs, solver2.composite.coefs, 'container solver', None
def test_multiple_lasso_dual(n=500):
"""
Check that the solution of the lasso signal approximator dual composite is soft-thresholding even when specified with multiple seminorms
"""
l1 = 1
sparsity1 = R.l1norm(n, lagrange=l1 * 0.75)
sparsity2 = R.l1norm(n, lagrange=l1 * 0.25)
x = np.random.normal(0, 1, n)
loss = R.quadratic.shift(-x, coef=0.5)
p = R.dual_problem.fromprimal(loss, sparsity1, sparsity2)
t1 = time.time()
solver = R.FISTA(p)
solver.debug = True
vals = solver.fit(tol=1.0e-16)
soln = p.primal
t2 = time.time()
print t2 - t1
st = np.maximum(np.fabs(x) - l1, 0) * np.sign(x)
np.testing.assert_almost_equal(soln, st, decimal=3)
p = R.container(loss, sparsity1, sparsity2)
t1 = time.time()
solver = R.FISTA(p)
solver.debug = True
vals = solver.fit(tol=1.0e-16)
soln = p.primal
t2 = time.time()
print t2 - t1
st = np.maximum(np.fabs(x) - l1, 0) * np.sign(x)
print soln[range(10)]
print st[range(10)]
np.testing.assert_almost_equal(soln, st, decimal=3)
def test_conjugate_solver():
# Solve Lagrange problem
Y = np.random.standard_normal(500)
Y[100:150] += 7
Y[250:300] += 14
loss = R.quadratic.shift(-Y, coef=0.5)
sparsity = R.l1norm(len(Y), lagrange=1.4)
D = sparse.csr_matrix((np.identity(500) + np.diag([-1] * 499, k=1))[:-1])
fused = R.l1norm.linear(D, lagrange=25.5)
problem = R.container(loss, sparsity, fused)
solver = R.FISTA(problem)
solver.fit(max_its=500, tol=1e-10)
solution = solver.composite.coefs
# Solve constrained version
delta1 = np.fabs(D * solution).sum()
delta2 = np.fabs(solution).sum()
fused_constraint = R.l1norm.linear(D, bound=delta1)
sparsity_constraint = R.l1norm(500, bound=delta2)
constrained_problem = R.container(loss, fused_constraint,
sparsity_constraint)
constrained_solver = R.FISTA(constrained_problem)
vals = constrained_solver.fit(max_its=500, tol=1e-10)
constrained_solution = constrained_solver.composite.coefs
npt.assert_almost_equal(np.fabs(constrained_solution).sum(), delta2, 3)
npt.assert_almost_equal(np.fabs(D * constrained_solution).sum(), delta1, 3)
# Solve with (shifted) conjugate function
loss = R.quadratic.shift(-Y, coef=0.5)
true_conjugate = R.quadratic.shift(Y, coef=0.5)
problem = R.container(loss, fused_constraint, sparsity_constraint)
solver = R.FISTA(problem.conjugate_composite(true_conjugate))
solver.fit(max_its=500, tol=1e-10)
conjugate_coefs = problem.conjugate_primal_from_dual(
solver.composite.coefs)
# Solve with generic conjugate function
loss = R.quadratic.shift(-Y, coef=0.5)
problem = R.container(loss, fused_constraint, sparsity_constraint)
solver2 = R.FISTA(problem.conjugate_composite(conjugate_tol=1e-12))
solver2.fit(max_its=500, tol=1e-10)
conjugate_coefs_gen = problem.conjugate_primal_from_dual(
solver2.composite.coefs)
d1 = np.linalg.norm(solution -
constrained_solution) / np.linalg.norm(solution)
d2 = np.linalg.norm(solution - conjugate_coefs) / np.linalg.norm(solution)
d3 = np.linalg.norm(solution -
conjugate_coefs_gen) / np.linalg.norm(solution)
npt.assert_array_less(d1, 0.01)
npt.assert_array_less(d2, 0.01)
npt.assert_array_less(d3, 0.01)
def test_simple_problem_nonsmooth(self):
tests = []
atom, q = self.atom, self.q
loss = self.loss
p2 = copy(atom)
p2.quadratic = atom.quadratic + q
problem = rr.simple_problem.nonsmooth(p2)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-14,
FISTA=self.FISTA,
coef_stop=self.coef_stop,
min_its=100)
gg = rr.gengrad(
problem,
2.) # this lipschitz constant is based on knowing our loss...
tests.append((atom.proximal(q), gg,
'solving prox with gengrad\n %s ' % str(self)))
tests.append((atom.proximal(q), atom.solve(q),
'solving prox with solve method\n %s ' % str(self)))
tests.append((
atom.proximal(q), solver.composite.coefs,
'solving prox with simple_problem.nonsmooth with monotonicity\n %s '
% str(self)))
# use the solve method
p3 = copy(atom)
p3.quadratic = atom.quadratic + q
soln = p3.solve(tol=1.e-14, min_its=10)
tests.append((atom.proximal(q), soln,
'solving prox with solve method\n %s ' % str(self)))
p4 = copy(atom)
p4.quadratic = atom.quadratic + q
problem = rr.simple_problem.nonsmooth(p4)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-14,
monotonicity_restart=False,
coef_stop=self.coef_stop,
FISTA=self.FISTA,
min_its=100)
tests.append((
atom.proximal(q), solver.composite.coefs,
'solving prox with simple_problem.nonsmooth with no monotonocity\n %s '
% str(self)))
if not self.interactive:
for test in tests:
yield (all_close, ) + test + (self, )
else:
for test in tests:
yield all_close(*((test + (self, ))))
def test_lasso_separable():
"""
This test verifies that the specification of a separable
penalty yields the same results as having two linear_atoms
with selector matrices. The penalty here is a lasso, i.e. l1
penalty.
"""
X = np.random.standard_normal((100,20))
Y = np.random.standard_normal((100,)) + np.dot(X, np.random.standard_normal(20))
penalty1 = rr.l1norm(10, lagrange=1.2)
penalty2 = rr.l1norm(10, lagrange=1.2)
penalty = rr.separable((20,), [penalty1, penalty2], [slice(0,10), slice(10,20)], test_for_overlap=True)
# ensure code is tested
print(penalty1.latexify())
print(penalty.latexify())
print(penalty.conjugate)
print(penalty.dual)
print(penalty.seminorm(np.ones(penalty.shape)))
print(penalty.constraint(np.ones(penalty.shape), bound=2.))
pencopy = copy(penalty)
pencopy.set_quadratic(rr.identity_quadratic(1,0,0,0))
pencopy.conjugate
# solve using separable
loss = rr.quadratic_loss.affine(X, -Y, coef=0.5)
problem = rr.separable_problem.fromatom(penalty, loss)
solver = rr.FISTA(problem)
solver.fit(min_its=200, tol=1.0e-12)
coefs = solver.composite.coefs
# solve using the usual composite
penalty_all = rr.l1norm(20, lagrange=1.2)
problem_all = rr.container(loss, penalty_all)
solver_all = rr.FISTA(problem_all)
solver_all.fit(min_its=100, tol=1.0e-12)
coefs_all = solver_all.composite.coefs
# solve using the selectors
penalty_s = [rr.linear_atom(p, rr.selector(g, (20,))) for p, g in
zip(penalty.atoms, penalty.groups)]
problem_s = rr.container(loss, *penalty_s)
solver_s = rr.FISTA(problem_s)
solver_s.fit(min_its=500, tol=1.0e-12)
coefs_s = solver_s.composite.coefs
np.testing.assert_almost_equal(coefs, coefs_all)
np.testing.assert_almost_equal(coefs, coefs_s)
def test_affine_linear_offset_l1norm():
"""
Test linear, affine and offset with the l1norm atom
"""
n = 1000
p = 10
X = np.random.standard_normal((n,p))
Y = 10*np.random.standard_normal(n)
coefs = []
loss = rr.quadratic.affine(X,-Y, coef=0.5)
sparsity = rr.l1norm(p, lagrange=5.)
problem = rr.container(loss, sparsity)
solver = rr.FISTA(problem)
solver.fit(debug=False, tol=1e-10)
coefs.append(1.*solver.composite.coefs)
loss = rr.quadratic.affine(X,-Y, coef=0.5)
sparsity = rr.l1norm.linear(np.eye(p), lagrange=5.)
problem = rr.container(loss, sparsity)
solver = rr.FISTA(problem)
solver.fit(debug=False, tol=1e-10)
coefs.append(1.*solver.composite.coefs)
loss = rr.quadratic.affine(X,-Y, coef=0.5)
sparsity = rr.l1norm.affine(np.eye(p),np.zeros(p), lagrange=5.)
problem = rr.container(loss, sparsity)
solver = rr.FISTA(problem)
solver.fit(debug=False, tol=1e-10)
coefs.append(1.*solver.composite.coefs)
loss = rr.quadratic.affine(X,-Y, coef=0.5)
sparsity = rr.l1norm.linear(np.eye(p), lagrange=5., offset=np.zeros(p))
problem = rr.container(loss, sparsity)
solver = rr.FISTA(problem)
solver.fit(debug=False, tol=1e-10)
coefs.append(1.*solver.composite.coefs)
loss = rr.quadratic.affine(X,-Y, coef=0.5)
sparsity = rr.l1norm.shift(np.zeros(p), lagrange=5.)
problem = rr.container(loss, sparsity)
solver = rr.FISTA(problem)
solver.fit(debug=False, tol=1e-10)
coefs.append(1.*solver.composite.coefs)
for i,j in itertools.combinations(range(len(coefs)), 2):
npt.assert_almost_equal(coefs[i], coefs[j])
def test_simple_problem(self):
tests = []
atom, q, prox_center, L = self.atom, self.q, self.prox_center, self.L
loss = self.loss
problem = rr.simple_problem(loss, atom)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-12, FISTA=self.FISTA, coef_stop=self.coef_stop, min_its=100)
tests.append((atom.proximal(q), solver.composite.coefs, 'solving prox with simple_problem with monotonicity\n %s' % str(self)))
# write the loss in terms of a quadratic for the smooth loss and a smooth function...
q = rr.identity_quadratic(L, prox_center, 0, 0)
lossq = rr.quadratic_loss.shift(prox_center.copy(), coef=0.6*L)
lossq.quadratic = rr.identity_quadratic(0.4*L, prox_center.copy(), 0, 0)
problem = rr.simple_problem(lossq, atom)
tests.append((atom.proximal(q),
problem.solve(coef_stop=self.coef_stop,
FISTA=self.FISTA,
tol=1.0e-12),
'solving prox with simple_problem ' +
'with monotonicity but loss has identity_quadratic %s\n ' % str(self)))
problem = rr.simple_problem(loss, atom)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-12, monotonicity_restart=False,
coef_stop=self.coef_stop, FISTA=self.FISTA, min_its=100)
tests.append((atom.proximal(q), solver.composite.coefs, 'solving prox with simple_problem no monotonicity_restart\n %s' % str(self)))
d = atom.conjugate
problem = rr.simple_problem(loss, d)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-12, monotonicity_restart=False,
coef_stop=self.coef_stop, FISTA=self.FISTA, min_its=100)
tests.append((d.proximal(q), problem.solve(tol=1.e-12,
FISTA=self.FISTA,
coef_stop=self.coef_stop,
monotonicity_restart=False),
'solving dual prox with simple_problem no monotonocity\n %s ' % str(self)))
if not self.interactive:
for test in tests:
yield (all_close,) + test + (self,)
else:
for test in tests:
yield all_close(*((test + (self,))))
def test_container(self):
tests = []
atom, q, prox_center, L = self.atom, self.q, self.prox_center, self.L
loss = self.loss
problem = rr.container(loss, atom)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-12,
coef_stop=self.coef_stop,
FISTA=self.FISTA,
min_its=100)
tests.append((atom.proximal(q), solver.composite.coefs,
'solving atom prox with container\n %s ' % str(self)))
# write the loss in terms of a quadratic for the smooth loss and a smooth function...
q = rr.identity_quadratic(L, prox_center, 0, 0)
lossq = rr.quadratic.shift(prox_center.copy(), coef=0.6 * L)
lossq.quadratic = rr.identity_quadratic(0.4 * L, prox_center.copy(), 0,
0)
problem = rr.container(lossq, atom)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-12, FISTA=self.FISTA, coef_stop=self.coef_stop)
tests.append((atom.proximal(q),
problem.solve(tol=1.e-12,
FISTA=self.FISTA,
coef_stop=self.coef_stop),
'solving prox with container with monotonicity ' +
'but loss has identity_quadratic\n %s ' % str(self)))
d = atom.conjugate
problem = rr.container(d, loss)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-12,
coef_stop=self.coef_stop,
FISTA=self.FISTA,
min_its=100)
tests.append((d.proximal(q), solver.composite.coefs,
'solving dual prox with container\n %s ' % str(self)))
if not self.interactive:
for test in tests:
yield (all_close, ) + test + (self, )
else:
for test in tests:
yield all_close(*((test + (self, ))))
def group_lasso_example():
def selector(p, slice):
return np.identity(p)[slice]
penalties = [R.l2norm(selector(500, slice(i*100,(i+1)*100)), lagrange=.1) for i in range(5)]
penalties[0].lagrange = 250.
penalties[1].lagrange = 225.
penalties[2].lagrange = 150.
penalties[3].lagrange = 100.
X = np.random.standard_normal((1000,500))
Y = np.random.standard_normal((1000,))
loss = R.quadratic.affine(X, -Y, coef=0.5)
group_lasso = R.container(loss, *penalties)
solver=R.FISTA(group_lasso)
solver.debug = True
vals = solver.fit(max_its=2000, min_its=20,tol=1e-10)
soln = solver.composite.coefs
# solution
pylab.figure(num=1)
pylab.clf()
pylab.plot(soln, c='g')
# objective values
pylab.figure(num=2)
pylab.clf()
pylab.plot(vals)
def fused_example():
x=np.random.standard_normal(500); x[100:150] += 7
sparsity = R.l1norm(500, lagrange=1.3)
D = (np.identity(500) + np.diag([-1]*499,k=1))[:-1]
fused = R.l1norm.linear(D, lagrange=10.5)
loss = R.quadratic.shift(-x, coef=0.5)
pen = R.container(loss, sparsity,fused)
solver = R.FISTA(pen)
vals = solver.fit()
soln = solver.composite.coefs
# solution
pylab.figure(num=1)
pylab.clf()
pylab.plot(soln, c='g')
pylab.scatter(np.arange(x.shape[0]), x)
# objective values
pylab.figure(num=2)
pylab.clf()
pylab.plot(vals)
def test_lasso(n=100):
l1 = 1.
sparsity = R.l1norm(n, lagrange=l1)
X = np.random.standard_normal((5000,n))
Y = np.random.standard_normal((5000,))
regloss = R.quadratic.affine(-X,Y)
p=R.container(regloss, sparsity)
solver=R.FISTA(p)
solver.debug = True
t1 = time.time()
vals1 = solver.fit(max_its=800)
t2 = time.time()
dt1 = t2 - t1
soln = solver.composite.coefs
time.sleep(5)
print soln[range(10)]
print solver.composite.objective(soln)
print "Times", dt1
def test_lasso():
'''
this test verifies that the l1 prox can be solved
by a primal/dual specification
obviously, we don't to solve the l1 prox this way,
but it verifies that specification is working correctly
'''
l1 = rr.l1norm(4, lagrange=2.)
l1.quadratic = rr.identity_quadratic(0.5, 0, None, 0.)
X = np.random.standard_normal((10, 4))
Y = np.random.standard_normal(10) + 3
loss = rr.quadratic_loss.affine(X, -Y, coef=0.5)
p2 = rr.separable_problem.singleton(l1, loss)
solver2 = rr.FISTA(p2)
solver2.fit(tol=1.0e-14, min_its=100)
f = p2.objective
ans = scipy.optimize.fmin_powell(f, np.zeros(4), ftol=1.0e-12, xtol=1.e-10)
print(f(solver2.composite.coefs), f(ans))
np.testing.assert_allclose(ans + 0.1,
solver2.composite.coefs + 0.1,
rtol=1.e-3)
def test_group_lasso_sparse(n=100):
def selector(p, slice):
return np.identity(p)[slice]
def selector_sparse(p, slice):
return sparse.csr_matrix(np.identity(p)[slice])
X = np.random.standard_normal((1000,500))
Y = np.random.standard_normal((1000,))
loss = R.quadratic.affine(X, -Y, coef=0.5)
penalties = [R.l2norm.linear(selector(500, slice(i*100,(i+1)*100)), lagrange=.1) for i in range(5)]
penalties[0].lagrange = 250.
penalties[1].lagrange = 225.
penalties[2].lagrange = 150.
penalties[3].lagrange = 100.
group_lasso = R.container(loss, *penalties)
solver=R.FISTA(group_lasso)
solver.debug = True
t1 = time.time()
vals = solver.fit(max_its=2000, min_its=20,tol=1e-8)
soln1 = solver.composite.coefs
t2 = time.time()
dt1 = t2 - t1
print soln1[range(10)]
def test_logistic_offset():
"""
Test the equivalence of binary/count specification in logistic_likelihood
"""
#Form the count version of the problem
trials = np.random.binomial(5, 0.5, 10) + 1
successes = np.random.binomial(trials, 0.5, len(trials))
n = len(successes)
p = 2 * n
X = np.hstack(
[np.ones((n, 1)),
np.random.normal(0, 1, n * p).reshape((n, p))])
loss = rr.logistic_loglike.linear(X, successes=successes, trials=trials)
weights = np.ones(p + 1)
weights[0] = 0.
penalty = rr.quadratic_loss.linear(weights, coef=.1, diag=True)
prob1 = rr.container(loss, penalty)
solver1 = rr.FISTA(prob1)
vals = solver1.fit(tol=1e-12)
solution1 = solver1.composite.coefs
diff = 0.1
loss = rr.logistic_loglike.affine(X,
successes=successes,
trials=trials,
offset=diff * np.ones(n))
weights = np.ones(p + 1)
weights[0] = 0.
penalty = rr.quadratic_loss.linear(weights, coef=.1, diag=True)
prob2 = rr.container(loss, penalty)
solver2 = rr.FISTA(prob2)
vals = solver2.fit(tol=1e-12)
solution2 = solver2.composite.coefs
ind = np.arange(1, p + 1)
print(solution1[np.arange(5)])
print(solution2[np.arange(5)])
npt.assert_array_almost_equal(solution1[ind], solution2[ind], 3)
npt.assert_almost_equal(solution1[0] - diff, solution2[0], 2)
def test_gengrad():
Z = np.random.standard_normal(100) * 4
p = rr.l1norm(100, lagrange=0.13)
L = 0.14
loss = rr.quadratic_loss.shift(Z, coef=L)
problem = rr.simple_problem(loss, p)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-10, debug=True)
simple_coef = solver.composite.coefs
prox_coef = p.proximal(rr.identity_quadratic(L, Z, 0, 0))
p2 = rr.l1norm(100, lagrange=0.13)
p2 = copy(p)
p2.quadratic = rr.identity_quadratic(L, Z, 0, 0)
problem = rr.simple_problem.nonsmooth(p2)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-14, debug=True)
simple_nonsmooth_coef = solver.composite.coefs
p = rr.l1norm(100, lagrange=0.13)
p.quadratic = rr.identity_quadratic(L, Z, 0, 0)
problem = rr.simple_problem.nonsmooth(p)
simple_nonsmooth_gengrad = rr.gengrad(problem, L, tol=1.0e-10)
p = rr.l1norm(100, lagrange=0.13)
problem = rr.separable_problem.singleton(p, loss)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-10)
separable_coef = solver.composite.coefs
loss2 = rr.quadratic_loss.shift(Z, coef=0.6 * L)
loss2.quadratic = rr.identity_quadratic(0.4 * L, Z, 0, 0)
p.coefs *= 0
problem2 = rr.simple_problem(loss2, p)
loss2_coefs = problem2.solve(coef_stop=True)
solver2 = rr.FISTA(problem2)
solver2.fit(tol=1.0e-10, debug=True, coef_stop=True)
yield all_close, prox_coef, simple_nonsmooth_gengrad, 'prox to nonsmooth gengrad', None
yield all_close, prox_coef, separable_coef, 'prox to separable', None
yield all_close, prox_coef, simple_nonsmooth_coef, 'prox to simple_nonsmooth', None
yield all_close, prox_coef, simple_coef, 'prox to simple', None
yield all_close, prox_coef, loss2_coefs, 'simple where loss has quadratic 1', None
yield all_close, prox_coef, solver2.composite.coefs, 'simple where loss has quadratic 2', None
def lasso_via_dual_split():
def selector(p, slice):
return np.identity(p)[slice]
penalties = [R.l1norm(selector(500, slice(i*100,(i+1)*100)), lagrange=0.2) for i in range(5)]
x = np.random.standard_normal(500)
loss = R.quadratic.shift(-x, coef=0.5)
lasso = R.container(loss,*penalties)
solver = R.FISTA(lasso)
np.testing.assert_almost_equal(np.maximum(np.fabs(x)-0.2, 0) * np.sign(x), solver.composite.coefs, decimal=3)
def test_logistic_counts():
"""
Test the equivalence of binary/count specification in logistic_deviance
"""
#Form the count version of the problem
trials = np.random.binomial(5,0.5,100)+1
successes = np.random.binomial(trials,0.5,len(trials))
n = len(successes)
p = 2*n
X = np.random.normal(0,1,n*p).reshape((n,p))
loss = rr.logistic_deviance.linear(X, successes=successes, trials=trials)
penalty = rr.quadratic(p, coef=1.)
prob1 = rr.container(loss, penalty)
solver1 = rr.FISTA(prob1)
solver1.fit()
solution1 = solver1.composite.coefs
#Form the binary version of the problem
Ynew = []
Xnew = []
for i, (s,n) in enumerate(zip(successes,trials)):
Ynew.append([1]*s + [0]*(n-s))
for j in range(n):
Xnew.append(X[i,:])
Ynew = np.hstack(Ynew)
Xnew = np.vstack(Xnew)
loss = rr.logistic_deviance.linear(Xnew, successes=Ynew)
penalty = rr.quadratic(p, coef=1.)
prob2 = rr.container(loss, penalty)
solver2 = rr.FISTA(prob2)
solver2.fit()
solution2 = solver2.composite.coefs
npt.assert_array_almost_equal(solution1, solution2, 3)
def group_lasso_signal_approx():
def selector(p, slice):
return np.identity(p)[slice]
penalties = [R.l2norm(selector(500, slice(i*100,(i+1)*100)), lagrange=10.) for i in range(5)]
loss = R.quadratic.shift(-x, coef=0.5)
group_lasso = R.container(loss, **penalties)
x = np.random.standard_normal(500)
solver = R.FISTA(group_lasso)
solver.fit()
a = solver.composite.coefs
def test_gengrad_blocknorms():
Z = np.random.standard_normal((10, 10)) * 4
p = rr.l1_l2((10, 10), lagrange=0.13)
dual = p.conjugate
L = 0.23
loss = rr.quadratic_loss.shift(Z, coef=L)
problem = rr.simple_problem(loss, p)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-10, debug=True)
simple_coef = solver.composite.coefs
q = rr.identity_quadratic(L, Z, 0, 0)
prox_coef = p.proximal(q)
p2 = copy(p)
p2.quadratic = rr.identity_quadratic(L, Z, 0, 0)
problem = rr.simple_problem.nonsmooth(p2)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-14, debug=True)
simple_nonsmooth_coef = solver.composite.coefs
p = rr.l1_l2((10, 10), lagrange=0.13)
p.quadratic = rr.identity_quadratic(L, Z, 0, 0)
problem = rr.simple_problem.nonsmooth(p)
simple_nonsmooth_gengrad = rr.gengrad(problem, L, tol=1.0e-10)
p = rr.l1_l2((10, 10), lagrange=0.13)
problem = rr.separable_problem.singleton(p, loss)
solver = rr.FISTA(problem)
solver.fit(tol=1.0e-10)
separable_coef = solver.composite.coefs
yield (all_close, prox_coef, simple_coef, 'prox to simple', None)
yield (all_close, prox_coef, simple_nonsmooth_gengrad,
'prox to nonsmooth gengrad', None)
yield (all_close, prox_coef, separable_coef, 'prox to separable', None)
yield (all_close, prox_coef, simple_nonsmooth_coef,
'prox to simple_nonsmooth', None)
def __init__(self, X, initial=None, lagrange=1, rho=1):
self.X = R.affine_transform(X, None)
self.atom = R.l1norm(X.shape[1], l)
self.rho = rho
self.loss = R.quadratic.affine(X,
-np.zeros(X.shape[0]),
lagrange=rho / 2.)
self.lasso = R.container(self.loss, self.atom)
self.solver = R.FISTA(self.lasso.problem())
if initial is None:
self.beta[:] = np.random.standard_normal(self.atom.primal_shape)
else:
self.beta[:] = initial
def test_1d_fused_lasso():
"""
Check the 1d fused lasso solution using an equivalent lasso formulation
"""
n = 100
l1 = 1.
D = (np.identity(n) - np.diag(np.ones(n - 1), -1))[1:]
extra = np.zeros(n)
extra[0] = 1.
D = np.vstack([D, extra])
D = sparse.csr_matrix(D)
fused = R.l1norm.linear(D, lagrange=l1)
X = np.random.standard_normal((2 * n, n))
Y = np.random.standard_normal((2 * n, ))
loss = R.quadratic.affine(X, -Y, coef=0.5)
fused_lasso = R.container(loss, fused)
solver = R.FISTA(fused_lasso)
vals1 = solver.fit(max_its=25000, tol=1e-10)
soln1 = solver.composite.coefs
B = np.array(sparse.tril(np.ones((n, n))).todense())
X2 = np.dot(X, B)
loss = R.quadratic.affine(X2, -Y, coef=0.5)
sparsity = R.l1norm(n, lagrange=l1)
lasso = R.container(loss, sparsity)
solver = R.FISTA(lasso)
solver.fit(tol=1e-10)
soln2 = np.dot(B, solver.composite.coefs)
npt.assert_array_almost_equal(soln1, soln2, 3)
def test_lasso_dual_with_monotonicity():
"""
restarting is funny for this simple problem
"""
l1 = .1
sparsity = R.l1norm(10, lagrange=l1)
x = np.arange(10) - 5
loss = R.quadratic.shift(-x, coef=0.5)
pen = R.simple_problem(loss, sparsity)
solver = R.FISTA(pen)
solver.fit()
soln = solver.composite.coefs
st = np.maximum(np.fabs(x) - l1, 0) * np.sign(x)
np.testing.assert_almost_equal(soln, st, decimal=3)
def test_l1_constraint():
"""
Test using the l1norm in bound form
"""
p = 1000
sparsity = R.l1norm(p, bound=5.)
prob = R.simple_problem.nonsmooth(sparsity)
prob.coefs[:] = np.random.standard_normal(1000)
problem = prob
solver = R.FISTA(problem)
vals = solver.fit(tol=1e-8, max_its=500)
solution = solver.composite.coefs
npt.assert_almost_equal(np.fabs(solution).sum(), sparsity.bound, 3)