def run(backend=SUPPORTED_BACKENDS[0], quiet=True):
num_rows = 128
subspace_dimension = 3
matrix = np.random.normal(size=(num_rows, num_rows))
matrix = 0.5 * (matrix + matrix.T)
manifold = Grassmann(num_rows, subspace_dimension)
cost, euclidean_gradient, euclidean_hessian = create_cost_and_derivates(
manifold, matrix, backend)
problem = pymanopt.Problem(
manifold,
cost,
euclidean_gradient=euclidean_gradient,
euclidean_hessian=euclidean_hessian,
)
optimizer = TrustRegions(verbosity=2 * int(not quiet))
estimated_spanning_set = optimizer.run(problem,
Delta_bar=8 *
np.sqrt(subspace_dimension)).point
if quiet:
return
eigenvalues, eigenvectors = np.linalg.eig(matrix)
column_indices = np.argsort(eigenvalues)[-subspace_dimension:]
spanning_set = eigenvectors[:, column_indices]
print(
"Geodesic distance between true and estimated dominant subspace:",
manifold.dist(spanning_set, estimated_spanning_set),
)
def setUp(self):
self.m = m = 5
self.n = n = 2
self.k = k = 1
self.man = Grassmann(m, n, k=k)
self.proj = lambda x, u: u - npa.dot(x, npa.dot(x.T, u))
def run(backend=SUPPORTED_BACKENDS[0], quiet=True):
"""This example generates a random 128 x 128 symmetric matrix and finds the
dominant invariant 3 dimensional subspace for this matrix, i.e., it finds
the subspace spanned by the three eigenvectors with the largest
eigenvalues.
"""
num_rows = 128
subspace_dimension = 3
matrix = rnd.randn(num_rows, num_rows)
matrix = 0.5 * (matrix + matrix.T)
cost, egrad, ehess = create_cost_egrad_ehess(
backend, matrix, subspace_dimension)
manifold = Grassmann(num_rows, subspace_dimension)
problem = pymanopt.Problem(manifold, cost=cost, egrad=egrad, ehess=ehess)
if quiet:
problem.verbosity = 0
solver = TrustRegions()
estimated_spanning_set = solver.solve(
problem, Delta_bar=8*np.sqrt(subspace_dimension))
if quiet:
return
eigenvalues, eigenvectors = la.eig(matrix)
column_indices = np.argsort(eigenvalues)[-subspace_dimension:]
spanning_set = eigenvectors[:, column_indices]
print("Geodesic distance between true and estimated dominant subspace:",
manifold.dist(spanning_set, estimated_spanning_set))
def setUp(self):
self.m = m = 5
self.n = n = 2
self.k = k = 1
self.manifold = Grassmann(m, n, k=k)
self.projection = lambda x, u: u - x @ x.T @ u
super().setUp()
def NG_sdr(X, y, m, v_w = 5, v_b = 5, verbosity=0, *args, **kwargs):
"""
X: array of N points on complex Gr(n, p); N x n x p array
aim to represent X by X_hat (N points on Gr(m, p), m < n)
where X_hat_i = R^T X_i, W \in St(n, m)
minimizing the projection error (using projection F-norm)
"""
N, n, p = X.shape
cpx = np.iscomplex(X).any() # true if X is complex-valued
if cpx:
gr = ComplexGrassmann(n, p)
man = ComplexGrassmann(n, m)
else:
gr = Grassmann(n, p)
man = Grassmann(n, m)
# distance matrix
dist_m = np.zeros((N, N))
for i in range(N):
for j in range(i):
dist_m[i, j] = gr.dist(X[i], X[j])
dist_m[j, i] = dist_m[i, j]
# affinity matrix
affinity = affinity_matrix(dist_m, y, v_w, v_b)
X_ = torch.from_numpy(X)
affinity_ = torch.from_numpy(affinity)
@pymanopt.function.PyTorch
def cost(A):
dm = torch.zeros((N, N))
for i in range(N):
for j in range(i):
dm[i, j] = dist_proj(torch.matmul(A.conj().t(), X_[i]), torch.matmul(A.conj().t(), X_[j]))**2
#dm[i, j] = gr_low.dist(X_proj[i], X_proj[j])**2
dm[j, i] = dm[i, j]
d2 = torch.mean(affinity_*dm)
return d2
# solver = ConjugateGradient()
solver = SteepestDescent()
problem = Problem(manifold=man, cost=cost, verbosity=verbosity)
A = solver.solve(problem)
tmp = np.array([A.conj().T for i in range(N)]) # N x m x n
X_low = multiprod(tmp, X) # N x m x p
X_low = np.array([qr(X_low[i])[0] for i in range(N)])
return X_low, A
def envelope(X_env, Y_env, u):
p, r = X_env.shape[1], Y_env.shape[1]
linear_model = LinearRegression().fit(X_env, Y_env)
err = Y_env - linear_model.predict(X_env)
Sigma_res = np.cov(err.transpose())
Sigma_Y = np.cov(Y_env.transpose())
def cost(Gamma):
X = np.matmul(Gamma, Gamma.T)
out = -np.log(
np.linalg.det(
np.matmul(np.matmul(X, Sigma_res), X) +
np.matmul(np.matmul(np.eye(r) - X, Sigma_Y),
np.eye(r) - X)))
return (np.array(out))
manifold = Grassmann(r, u)
# manifold = Stiefel(r, u)
problem = Problem(manifold=manifold, cost=cost, verbosity=0)
solver = SteepestDescent()
Gamma = solver.solve(problem)
PSigma1_hat = np.matmul(Gamma, Gamma.T)
PSigma2_hat = np.eye(r) - PSigma1_hat
beta_hat = np.matmul(PSigma1_hat, linear_model.coef_)
Sigma1_hat = np.matmul(np.matmul(PSigma1_hat, Sigma_res), PSigma1_hat)
Sigma2_hat = np.matmul(np.matmul(np.eye(r) - PSigma1_hat, Sigma_res),
np.eye(r) - PSigma1_hat)
alpha_hat = np.mean(Y_env - np.matmul(X_env, beta_hat.T), axis=0)
return (alpha_hat.reshape(1, r), beta_hat.reshape(p, r))
def setUp(self):
self.m = m = 5
self.n = n = 2
self.k = k = 1
self.man = Grassmann(m, n, k=k)
self.proj = lambda x, u: u - npa.dot(x, npa.dot(x.T, u))
def solve_manopt(X, d, cost, egrad, Wo=None):
D = X.shape[1]
manifold = Grassmann(height=D, width=d)
problem = Problem(manifold=manifold, cost=cost, egrad=egrad, verbosity=0)
solver = ConjugateGradient(mingradnorm=1e-3)
W = solver.solve(problem, x=Wo)
return W
def __init__(self, db):
self.cost_function = db['compute_cost']
self.gradient_function = db['compute_gradient']
# (1) Instantiate a manifold
#self.manifold = Stiefel(db['Dloader'].d, db['q'])
self.manifold = Grassmann(db['Dloader'].d, db['q'])
self.x_opt = None
self.cost_opt = None
self.db = db
def NG_dr1(X, verbosity = 0):
"""
X: array of N points on Gr(n, p); N x n x p array
aim to represent X by X_hat (N points on Gr(n-1, p))
where X_hat_i = A^T X_i, A \in St(n, n-1)
minimizing the projection error (using projection F-norm)
"""
N, n, p = X.shape
cpx = np.iscomplex(X).any() # true if X is complex-valued
if cpx:
man = Product([ComplexGrassmann(n, 1), Euclidean(p, 2)])
else:
man = Product([Grassmann(n, 1), Euclidean(p)])
X_ = torch.from_numpy(X)
@pymanopt.function.PyTorch
def cost(v, b):
vvT = torch.matmul(v, v.conj().t()) # n x n
if cpx:
b_ = b[:,0] + b[:,1]*1j
b_ = torch.unsqueeze(b_, axis=1)
else:
b_ = torch.unsqueeze(b, axis=1)
vbt = torch.matmul(v, b_.t()) # n x p
IvvT = torch.eye(n, dtype=X_.dtype) - vvT
d2 = 0
for i in range(N):
d2 = d2 + dist_proj(X_[i], torch.matmul(IvvT, X_[i]) + vbt)**2/N
#d2 = d2 + dist_proj(X_[i], torch.matmul(AAT, X_[i]))**2/N
return d2
solver = SteepestDescent()
problem = Problem(manifold=man, cost=cost, verbosity=verbosity)
theta = solver.solve(problem)
v = theta[0]
b_ = theta[1]
if cpx:
b = b_[:,0] + b_[:,1]*1j
b = np.expand_dims(b, axis=1)
else:
b = np.expand_dims(b_, axis=1)
R = ortho_complement(v)
tmp = np.array([R.conj().T for i in range(N)])
X_low = multiprod(tmp, X)
X_low = np.array([qr(X_low[i])[0] for i in range(N)])
return X_low, R, v, b
def sample_grassmann(d, p, n):
"""
Sample n points from the manifold of p-dimensional subspaces
of R^d using pymanopt.manifolds.grassmann.Grassmann.rand
"""
try:
with open(
"data/grassmann__" + str(d) + "_" + str(p) + "_" + str(n) +
".pkl", "rb") as f:
points = pkl.load(f)
except FileNotFoundError:
print("Sampling " + str(n) + " points from Grassmann(+" + str(d) +
"," + str(p) + ")...")
manifold = Grassmann(d, p)
points = []
for _ in tqdm(range(n)):
points.append(manifold.rand())
points = np.stack(points)
with open(
"data/grassmann__" + str(d) + "_" + str(p) + "_" + str(n) +
".pkl", "wb") as f:
pkl.dump(points, f)
return points
def NG_dr(X, m, verbosity=0, *args, **kwargs):
"""
X: array of N points on Gr(n, p); N x n x p array
aim to represent X by X_hat (N points on Gr(m, p), m < n)
where X_hat_i = R^T X_i, R \in St(n, m)
minimizing the projection error (using projection F-norm)
"""
N, n, p = X.shape
cpx = np.iscomplex(X).any() # true if X is complex-valued
if cpx:
man = Product([ComplexGrassmann(n, m), Euclidean(n, p, 2)])
else:
man = Product([Grassmann(n, m), Euclidean(n, p)])
X_ = torch.from_numpy(X)
@pymanopt.function.PyTorch
def cost(A, B):
AAT = torch.matmul(A, A.conj().t()) # n x n
if cpx:
B_ = B[:,:,0] + B[:,:,1]*1j
else:
B_ = B
IAATB = torch.matmul(torch.eye(n, dtype=X_.dtype) - AAT, B_) # n x p
d2 = 0
for i in range(N):
d2 = d2 + dist_proj(X_[i], torch.matmul(AAT, X_[i]) + IAATB)**2/N
#d2 = d2 + dist_proj(X_[i], torch.matmul(AAT, X_[i]))**2/N
return d2
#solver = ConjugateGradient()
solver = SteepestDescent()
problem = Problem(manifold=man, cost=cost, verbosity=verbosity)
theta = solver.solve(problem)
A = theta[0]
B = theta[1]
if cpx:
B_ = B[:,:,0] + B[:,:,1]*1j
else:
B_ = B
#tmp = np.array([A.T for i in range(N)])
tmp = np.array([A.conj().T for i in range(N)])
X_low = multiprod(tmp, X)
X_low = np.array([qr(X_low[i])[0] for i in range(N)])
return X_low, A, B_
def solve_manopt(X, d, cost, egrad):
D = X.shape[1]
manifold = Grassmann(height=D, width=d)
problem = Problem(manifold=manifold, cost=cost, egrad=egrad, verbosity=0)
solver = ConjugateGradient(mingradnorm=1e-3)
M = mean_riemann(X)
w, v = np.linalg.eig(M)
idx = w.argsort()[::-1]
v_ = v[:, idx]
Wo = v_[:, :d]
W = solver.solve(problem, x=Wo)
return W
def dominant_invariant_subspace(A, p):
"""
Returns an orthonormal basis of the dominant invariant p-subspace of A.
Arguments:
- A
A real, symmetric matrix A of size nxn
- p
integer p < n.
Returns:
A real, orthonormal matrix X of size nxp such that trace(X'*A*X)
is maximized. That is, the columns of X form an orthonormal basis
of a dominant subspace of dimension p of A. These span the same space
as the eigenvectors associated with the largest eigenvalues of A.
Sign is important: 2 is deemed a larger eigenvalue than -5.
"""
# Make sure the input matrix is square and symmetric
n = A.shape[0]
assert type(A) == np.ndarray, 'A must be a numpy array.'
assert np.isreal(A).all(), 'A must be real.'
assert A.shape[1] == n, 'A must be square.'
assert np.linalg.norm(A-A.T) < n * np.spacing(1), 'A must be symmetric.'
assert p <= n, 'p must be smaller than n.'
# Define the cost on the Grassmann manifold
Gr = Grassmann(n, p)
X = T.matrix()
cost = -T.dot(X.T, T.dot(A, X)).trace()
# Setup the problem
problem = Problem(man=Gr, ad_cost=cost, ad_arg=X)
# Create a solver object
solver = TrustRegions()
# Solve
Xopt = solver.solve(problem, Delta_bar=8*np.sqrt(p))
return Xopt
def nonlinear_eigenspace(L, k, alpha=1):
"""Nonlinear eigenvalue problem: total energy minimization.
This example is motivated in [1]_ and was adapted from the manopt toolbox
in Matlab.
TODO : check this
Parameters
----------
L : array, shape=(n_channels, n_channels)
Discrete Laplacian operator: the covariance matrix.
alpha : float
Given constant for optimization problem.
k : int
Determines how many eigenvalues are returned.
Returns
-------
Xsol : array, shape=(n_channels, n_channels)
Eigenvectors.
S0 : array
Eigenvalues.
References
----------
.. [1] "A Riemannian Newton Algorithm for Nonlinear Eigenvalue Problems",
Zhi Zhao, Zheng-Jian Bai, and Xiao-Qing Jin, SIAM Journal on Matrix
Analysis and Applications, 36(2), 752-774, 2015.
"""
n = L.shape[0]
assert L.shape[1] == n, 'L must be square.'
# Grassmann manifold description
manifold = Grassmann(n, k)
manifold._dimension = 1 # hack
# A solver that involves the hessian (check if correct TODO)
solver = TrustRegions()
# Cost function evaluation
@pymanopt.function.Callable
def cost(X):
rhoX = np.sum(X**2, 1, keepdims=True) # diag(X*X')
val = 0.5 * np.trace(X.T @ (L * X)) + \
(alpha / 4) * (rhoX.T @ mldivide(L, rhoX))
return val
# Euclidean gradient evaluation
@pymanopt.function.Callable
def egrad(X):
rhoX = np.sum(X**2, 1, keepdims=True) # diag(X*X')
g = L @ X + alpha * np.diagflat(mldivide(L, rhoX)) @ X
return g
# Euclidean Hessian evaluation
# Note: Manopt automatically converts it to the Riemannian counterpart.
@pymanopt.function.Callable
def ehess(X, U):
rhoX = np.sum(X**2, 1, keepdims=True) # np.diag(X * X')
rhoXdot = 2 * np.sum(X.dot(U), 1)
h = L @ U + alpha * np.diagflat(mldivide(L, rhoXdot)) @ X + \
alpha * np.diagflat(mldivide(L, rhoX)) @ U
return h
# Initialization as suggested in above referenced paper.
# randomly generate starting point for svd
x = np.random.randn(n, k)
[U, S, V] = linalg.svd(x, full_matrices=False)
x = U.dot(V.T)
S0, U0 = linalg.eig(L + alpha * np.diagflat(mldivide(L, np.sum(x**2, 1))))
# Call manoptsolve to automatically call an appropriate solver.
# Note: it calls the trust regions solver as we have all the required
# ingredients, namely, gradient and Hessian, information.
problem = Problem(manifold=manifold,
cost=cost,
egrad=egrad,
ehess=ehess,
verbosity=0)
Xsol = solver.solve(problem, U0)
return S0, Xsol
class TestSingleGrassmannManifold(unittest.TestCase):
def setUp(self):
self.m = m = 5
self.n = n = 2
self.k = k = 1
self.man = Grassmann(m, n, k=k)
self.proj = lambda x, u: u - npa.dot(x, npa.dot(x.T, u))
def test_dist(self):
x = self.man.rand()
y = self.man.rand()
np_testing.assert_almost_equal(self.man.dist(x, y),
self.man.norm(x, self.man.log(x, y)))
def test_ehess2rhess(self):
# Test this function at some randomly generated point.
x = self.man.rand()
u = self.man.randvec(x)
egrad = rnd.randn(self.m, self.n)
ehess = rnd.randn(self.m, self.n)
np_testing.assert_allclose(
testing.ehess2rhess(self.proj)(x, egrad, ehess, u),
self.man.ehess2rhess(x, egrad, ehess, u))
def test_retr(self):
# Test that the result is on the manifold and that for small
# tangent vectors it has little effect.
x = self.man.rand()
u = self.man.randvec(x)
xretru = self.man.retr(x, u)
np_testing.assert_allclose(multiprod(multitransp(xretru), xretru),
np.eye(self.n),
atol=1e-10)
u = u * 1e-6
xretru = self.man.retr(x, u)
np_testing.assert_allclose(xretru, x + u)
# def test_egrad2rgrad(self):
# def test_norm(self):
def test_rand(self):
# Just make sure that things generated are on the manifold and that
# if you generate two they are not equal.
X = self.man.rand()
np_testing.assert_allclose(multiprod(multitransp(X), X),
np.eye(self.n),
atol=1e-10)
Y = self.man.rand()
assert la.norm(X - Y) > 1e-6
# def test_randvec(self):
# def test_transp(self):
def test_exp_log_inverse(self):
s = self.man
x = s.rand()
y = s.rand()
u = s.log(x, y)
z = s.exp(x, u)
np_testing.assert_almost_equal(0, self.man.dist(y, z), decimal=5)
def test_log_exp_inverse(self):
s = self.man
x = s.rand()
u = s.randvec(x)
y = s.exp(x, u)
v = s.log(x, y)
# Check that the manifold difference between the tangent vectors u and
# v is 0
np_testing.assert_almost_equal(0, self.man.norm(x, u - v))
class TestMultiGrassmannManifold(unittest.TestCase):
def setUp(self):
self.m = m = 5
self.n = n = 2
self.k = k = 3
self.man = Grassmann(m, n, k=k)
self.proj = lambda x, u: u - npa.dot(x, npa.dot(x.T, u))
def test_dim(self):
assert self.man.dim == self.k * (self.m * self.n - self.n**2)
def test_typicaldist(self):
np_testing.assert_almost_equal(self.man.typicaldist,
np.sqrt(self.n * self.k))
def test_dist(self):
x = self.man.rand()
y = self.man.rand()
np_testing.assert_almost_equal(self.man.dist(x, y),
self.man.norm(x, self.man.log(x, y)))
def test_inner(self):
X = self.man.rand()
A = self.man.randvec(X)
B = self.man.randvec(X)
np_testing.assert_allclose(np.sum(A * B), self.man.inner(X, A, B))
def test_proj(self):
# Construct a random point X on the manifold.
X = self.man.rand()
# Construct a vector H in the ambient space.
H = rnd.randn(self.k, self.m, self.n)
# Compare the projections.
Hproj = H - multiprod(X, multiprod(multitransp(X), H))
np_testing.assert_allclose(Hproj, self.man.proj(X, H))
def test_retr(self):
# Test that the result is on the manifold and that for small
# tangent vectors it has little effect.
x = self.man.rand()
u = self.man.randvec(x)
xretru = self.man.retr(x, u)
np_testing.assert_allclose(multiprod(multitransp(xretru), xretru),
multieye(self.k, self.n),
atol=1e-10)
u = u * 1e-6
xretru = self.man.retr(x, u)
np_testing.assert_allclose(xretru, x + u)
# def test_egrad2rgrad(self):
def test_norm(self):
x = self.man.rand()
u = self.man.randvec(x)
np_testing.assert_almost_equal(self.man.norm(x, u), la.norm(u))
def test_rand(self):
# Just make sure that things generated are on the manifold and that
# if you generate two they are not equal.
X = self.man.rand()
np_testing.assert_allclose(multiprod(multitransp(X), X),
multieye(self.k, self.n),
atol=1e-10)
Y = self.man.rand()
assert la.norm(X - Y) > 1e-6
def test_randvec(self):
# Make sure things generated are in tangent space and if you generate
# two then they are not equal.
X = self.man.rand()
U = self.man.randvec(X)
np_testing.assert_allclose(multisym(multiprod(multitransp(X), U)),
np.zeros((self.k, self.n, self.n)),
atol=1e-10)
V = self.man.randvec(X)
assert la.norm(U - V) > 1e-6
# def test_transp(self):
def test_exp_log_inverse(self):
s = self.man
x = s.rand()
y = s.rand()
u = s.log(x, y)
z = s.exp(x, u)
np_testing.assert_almost_equal(0, self.man.dist(y, z))
def test_log_exp_inverse(self):
s = self.man
x = s.rand()
u = s.randvec(x)
y = s.exp(x, u)
v = s.log(x, y)
# Check that the manifold difference between the tangent vectors u and
# v is 0
np_testing.assert_almost_equal(0, self.man.norm(x, u - v))
class TestSingleGrassmannManifold(ManifoldTestCase):
def setUp(self):
self.m = m = 5
self.n = n = 2
self.k = k = 1
self.manifold = Grassmann(m, n, k=k)
self.projection = lambda x, u: u - x @ x.T @ u
super().setUp()
def test_dist(self):
x = self.manifold.random_point()
y = self.manifold.random_point()
np_testing.assert_almost_equal(
self.manifold.dist(x, y),
self.manifold.norm(x, self.manifold.log(x, y)),
)
def test_euclidean_to_riemannian_hessian(self):
# Test this function at some randomly generated point.
x = self.manifold.random_point()
u = self.manifold.random_tangent_vector(x)
egrad = np.random.normal(size=(self.m, self.n))
ehess = np.random.normal(size=(self.m, self.n))
np_testing.assert_allclose(
testing.euclidean_to_riemannian_hessian(self.projection)(x, egrad,
ehess, u),
self.manifold.euclidean_to_riemannian_hessian(x, egrad, ehess, u),
)
def test_retraction(self):
# Test that the result is on the manifold and that for small
# tangent vectors it has little effect.
x = self.manifold.random_point()
u = self.manifold.random_tangent_vector(x)
xretru = self.manifold.retraction(x, u)
np_testing.assert_allclose(multitransp(xretru) @ xretru,
np.eye(self.n),
atol=1e-10)
u = u * 1e-6
xretru = self.manifold.retraction(x, u)
np_testing.assert_allclose(xretru, x + u)
def test_first_order_function_approximation(self):
self.run_gradient_approximation_test()
def test_second_order_function_approximation(self):
self.run_hessian_approximation_test()
# def test_norm(self):
def test_random_point(self):
# Just make sure that things generated are on the manifold and that
# if you generate two they are not equal.
X = self.manifold.random_point()
np_testing.assert_allclose(multitransp(X) @ X,
np.eye(self.n),
atol=1e-10)
Y = self.manifold.random_point()
assert np.linalg.norm(X - Y) > 1e-6
# def test_random_tangent_vector(self):
# def test_transport(self):
def test_exp_log_inverse(self):
s = self.manifold
x = s.random_point()
y = s.random_point()
u = s.log(x, y)
z = s.exp(x, u)
np_testing.assert_almost_equal(0, self.manifold.dist(y, z), decimal=5)
def test_log_exp_inverse(self):
s = self.manifold
x = s.random_point()
u = s.random_tangent_vector(x)
y = s.exp(x, u)
v = s.log(x, y)
# Check that the manifold difference between the tangent vectors u and
# v is 0
np_testing.assert_almost_equal(0, self.manifold.norm(x, u - v))
class TestMultiGrassmannManifold(ManifoldTestCase):
def setUp(self):
self.m = m = 5
self.n = n = 2
self.k = k = 3
self.manifold = Grassmann(m, n, k=k)
self.projection = lambda x, u: u - x @ x.T @ u
super().setUp()
def test_dim(self):
assert self.manifold.dim == self.k * (self.m * self.n - self.n**2)
def test_typical_dist(self):
np_testing.assert_almost_equal(self.manifold.typical_dist,
np.sqrt(self.n * self.k))
def test_dist(self):
x = self.manifold.random_point()
y = self.manifold.random_point()
np_testing.assert_almost_equal(
self.manifold.dist(x, y),
self.manifold.norm(x, self.manifold.log(x, y)),
)
def test_inner_product(self):
X = self.manifold.random_point()
A = self.manifold.random_tangent_vector(X)
B = self.manifold.random_tangent_vector(X)
np_testing.assert_allclose(np.sum(A * B),
self.manifold.inner_product(X, A, B))
def test_projection(self):
# Construct a random point X on the manifold.
X = self.manifold.random_point()
# Construct a vector H in the ambient space.
H = np.random.normal(size=(self.k, self.m, self.n))
# Compare the projections.
Hproj = H - X @ multitransp(X) @ H
np_testing.assert_allclose(Hproj, self.manifold.projection(X, H))
def test_retraction(self):
# Test that the result is on the manifold and that for small
# tangent vectors it has little effect.
x = self.manifold.random_point()
u = self.manifold.random_tangent_vector(x)
xretru = self.manifold.retraction(x, u)
np_testing.assert_allclose(
multitransp(xretru) @ xretru,
multieye(self.k, self.n),
atol=1e-10,
)
u = u * 1e-6
xretru = self.manifold.retraction(x, u)
np_testing.assert_allclose(xretru, x + u)
def test_first_order_function_approximation(self):
self.run_gradient_approximation_test()
def test_second_order_function_approximation(self):
self.run_hessian_approximation_test()
def test_norm(self):
x = self.manifold.random_point()
u = self.manifold.random_tangent_vector(x)
np_testing.assert_almost_equal(self.manifold.norm(x, u),
np.linalg.norm(u))
def test_random_point(self):
# Just make sure that things generated are on the manifold and that
# if you generate two they are not equal.
X = self.manifold.random_point()
np_testing.assert_allclose(multitransp(X) @ X,
multieye(self.k, self.n),
atol=1e-10)
Y = self.manifold.random_point()
assert np.linalg.norm(X - Y) > 1e-6
def test_random_tangent_vector(self):
# Make sure things generated are in tangent space and if you generate
# two then they are not equal.
X = self.manifold.random_point()
U = self.manifold.random_tangent_vector(X)
np_testing.assert_allclose(
multisym(multitransp(X) @ U),
np.zeros((self.k, self.n, self.n)),
atol=1e-10,
)
V = self.manifold.random_tangent_vector(X)
assert np.linalg.norm(U - V) > 1e-6
# def test_transport(self):
def test_exp_log_inverse(self):
s = self.manifold
x = s.random_point()
y = s.random_point()
u = s.log(x, y)
z = s.exp(x, u)
np_testing.assert_almost_equal(0, self.manifold.dist(y, z))
def test_log_exp_inverse(self):
s = self.manifold
x = s.random_point()
u = s.random_tangent_vector(x)
y = s.exp(x, u)
v = s.log(x, y)
# Check that the manifold difference between the tangent vectors u and
# v is 0
np_testing.assert_almost_equal(0, self.manifold.norm(x, u - v))
def DR_geod_complex(X, m, verbosity=0):
"""
X: array of N points on Gr(n, p); N x n x p array
aim to represent X by X_hat (N points on Gr(m, p), m < n)
where X_hat_i = R^T X_i, W \in St(n, m)
minimizing the projection error (using geodesic distance)
"""
N, n, p = X.shape
Cgr = ComplexGrassmann(n, p, N)
Cgr_low = Grassmann(m, p)
Cgr_map = ComplexGrassmann(n, m) # n x m
XXT = multiprod(X, multihconj(X))
@pymanopt.function.Callable
def cost(Q):
tmp = np.array([np.matmul(Q, Q.T) for i in range(N)]) # N x n x n
new_X = multiprod(tmp, X) # N x n x p
q = np.array([qr(new_X[i])[0] for i in range(N)])
d2 = Cgr.dist(X, q)**2
return d2/N
@pymanopt.function.Callable
def egrad(Q):
"""
need to be fixed
"""
QQ = np.matmul(Q, multihconj(Q))
tmp = np.array([QQ for i in range(N)])
XQQX = multiprod(multiprod(multihconj(X), tmp), X)
lam, V = np.linalg.eigh(XQQX)
theta = np.arccos(np.sqrt(lam))
d = -2*theta/(np.cos(theta)*np.sin(theta))
Sig = np.array([np.diag(dd) for dd in d])
XV = multiprod(X,V)
eg = multiprod(XV, multiprod(Sig, multitransp(XV.conj())))
eg = np.mean(eg, axis = 0)
eg = np.matmul(eg, Q)
return eg
def egrad_num(R, eps = 1e-8+1e-8j):
"""
compute egrad numerically
"""
g = np.zeros(R.shape, dtype=np.complex128)
for i in range(n):
for j in range(m):
R1 = R.copy()
R2 = R.copy()
R1[i,j] += eps
R2[i,j] -= eps
g[i,j] = (cost(R1) - cost(R2))/(2*eps)
return g
# solver = ConjugateGradient()
solver = SteepestDescent()
problem = Problem(manifold=Cst, cost=cost, egrad=egrad, verbosity=verbosity)
Q_proj = solver.solve(problem)
tmp = np.array([multihconj(Q_proj) for i in range(N)])
X_low = multiprod(tmp, X)
X_low = X_low/np.expand_dims(np.linalg.norm(X_low, axis=1), axis = 2)
M_hat = compute_centroid(Cgr_low, X_low)
v_hat = var(Cgr_low, X_low, M_hat)/N
var_ratio = v_hat/v
return var_ratio, X_low, Q_proj
scores[j, (n-p)*p-1] = v[0] # signed distance
return scores[:,::-1]
if __name__ == '__main__':
m = 6
n = 10
p = 2
N = 15
print(f'Example 1: {N} points on Gr({p}, {m}) embedded in Gr({p}, {n})\n')
sig = 0.1
gr_low = Grassmann(m, p, N)
gr = Grassmann(n, p, N)
gr_map = Grassmann(n, m)
X_low = gr_low.rand() # N x m x p
A = gr_map.rand() # n x m
#B = np.random.normal(0, 0.1, (n, p)) # n x p
B = np.zeros((n,p))
AAT = np.matmul(A, A.T)
IAATB = np.matmul(np.eye(n) - AAT, B)
X = np.array([np.linalg.qr(np.matmul(A, X_low[i]) + IAATB)[0] for i in range(N)]) # N x n x p
X = gr.exp(X, sig * gr.randvec(X)) # perturb the emdedded X
scores = PNG(X, log = True)
print('\n')
def test_tangent_vector_multiplication(self):
# Regression test for https://github.com/pymanopt/pymanopt/issues/49.
man = Product((Euclidean(12), Grassmann(12, 3)))
x = man.rand()
eta = man.randvec(x)
np.float64(1.0) * eta
class TestSingleGrassmannManifold(unittest.TestCase):
def setUp(self):
self.m = m = 5
self.n = n = 2
self.k = k = 1
self.man = Grassmann(m, n, k=k)
self.proj = lambda x, u: u - npa.dot(x, npa.dot(x.T, u))
def test_dist(self):
x = self.man.rand()
y = self.man.rand()
np_testing.assert_almost_equal(self.man.dist(x, y),
self.man.norm(x, self.man.log(x, y)))
def test_ehess2rhess(self):
# Test this function at some randomly generated point.
x = self.man.rand()
u = self.man.randvec(x)
egrad = rnd.randn(self.m, self.n)
ehess = rnd.randn(self.m, self.n)
np_testing.assert_allclose(testing.ehess2rhess(self.proj)(x, egrad,
ehess, u),
self.man.ehess2rhess(x, egrad, ehess, u))
def test_retr(self):
# Test that the result is on the manifold and that for small
# tangent vectors it has little effect.
x = self.man.rand()
u = self.man.randvec(x)
xretru = self.man.retr(x, u)
np_testing.assert_allclose(multiprod(multitransp(xretru), xretru),
np.eye(self.n),
atol=1e-10)
u = u * 1e-6
xretru = self.man.retr(x, u)
np_testing.assert_allclose(xretru, x + u)
# def test_egrad2rgrad(self):
# def test_norm(self):
def test_rand(self):
# Just make sure that things generated are on the manifold and that
# if you generate two they are not equal.
X = self.man.rand()
np_testing.assert_allclose(multiprod(multitransp(X), X),
np.eye(self.n), atol=1e-10)
Y = self.man.rand()
assert la.norm(X - Y) > 1e-6
# def test_randvec(self):
# def test_transp(self):
def test_exp_log_inverse(self):
s = self.man
x = s.rand()
y = s.rand()
u = s.log(x, y)
z = s.exp(x, u)
np_testing.assert_almost_equal(0, self.man.dist(y, z), decimal=5)
def test_log_exp_inverse(self):
s = self.man
x = s.rand()
u = s.randvec(x)
y = s.exp(x, u)
v = s.log(x, y)
# Check that the manifold difference between the tangent vectors u and
# v is 0
np_testing.assert_almost_equal(0, self.man.norm(x, u - v))
def findSingleLP(X, d, k, sigma, embMethod='lpp'):
D, N = X.shape
W = np.zeros((N, N))
B = np.zeros((N, N))
if embMethod == 'pca':
for i in range(N - 1):
for j in range(i + 1, N):
W[i, j] = 1.0 / N
W = 0.5 * (W + W.T)
B = np.eye(N)
L = B - W
M1 = X.dot(L).dot(X.T)
Mc = np.eye(M1.shape[0])
elif embMethod == 'lpp':
G = kneighbors_graph(X.T, k, mode='distance',
include_self=False).toarray()
W = 0.5 * (G + G.T)
W[W != 0] = np.exp(-W[W != 0] / (2 * sigma * sigma))
B = np.diag(np.sum(W, axis=0))
L = B - W
M1 = X.dot(L).dot(X.T)
Mc = X.dot(B).dot(X.T)
elif embMethod == 'rand':
Gnk = Grassmann(D, 2)
proj = Gnk.rand()
return [proj]
elif embMethod == 'syn':
proj = np.zeros((D, 2))
card = 2
#ids = np.arange(D)
ids = np.array([1, 0, 4, 3]) # For ecoli 2
#ids = np.array([2,7,3,0]) # For yeast 2
#ids = np.array([12, 39, 5, 0, 45, 43]) # For seaWater 3
#ids = np.array([0, 46, 5, 14, 11, 40, 49, 43]) # For seaWater 4
np.random.shuffle(ids)
#print ids
proj[ids[:card], 0] = 1 / np.sqrt(card)
proj[ids[card:2 * card], 1] = 1 / np.sqrt(card)
#proj[ids[card-1:2*card-1],1] = 1/np.sqrt(card) # For cities
return [proj]
u, s = eig(M1)
if np.min(u) < 0:
M1 = M1 - np.min(u) * np.eye(M1.shape[0])
u, s = eig(Mc)
if np.min(u) < 0:
Mc = Mc - np.min(u) * np.eye(Mc.shape[0])
eigvals, eigvecs = eig(M1, Mc)
eigvecs = np.dot(sp.linalg.sqrtm(Mc), eigvecs)
if embMethod == 'pca':
ind = np.argsort(-eigvals)
proj = eigvecs[:, ind[0:d]]
elif embMethod == 'lpp':
ind = np.argsort(eigvals)
proj = eigvecs[:, ind[0:d]]
return [proj]
def RidgeAlternating(X,
f,
U0,
degree=1,
maxiter=100,
tol=1e-10,
history=False,
disp=False,
gtol=1e-6,
inner_iter=20):
if len(f.shape) == 1:
f = f.reshape(-1, 1)
# Instantiate the polynomial approximation
rs = PolynomialApproximation(N=degree)
# Instantiate the Grassmann manifold
m, n = U0.shape
manifold = Grassmann(m, n)
if history:
hist = {}
hist['U'] = []
hist['residual'] = []
hist['inner_steps'] = []
# Alternating minimization
i = 0
res = 1e9
while i < maxiter and res > tol:
# Train the polynomial approximation with projected points
Y = np.dot(X, U0)
rs.train(Y, f)
# Minimize residual with polynomial over Grassmann
func = lambda y: _res(y, X, f, rs)
grad = lambda y: _dres(y, X, f, rs)
problem = Problem(manifold=manifold,
cost=func,
egrad=grad,
verbosity=0)
if history:
solver = SteepestDescent(logverbosity=1,
mingradnorm=gtol,
maxiter=inner_iter,
minstepsize=tol)
U1, log = solver.solve(problem, x=U0)
else:
solver = SteepestDescent(logverbosity=0,
mingradnorm=gtol,
maxiter=inner_iter,
minstepsize=tol)
U1 = solver.solve(problem, x=U0)
# Evaluate and store the residual
res = func(U1) # This is the squared mismatch
if history:
hist['U'].append(U1)
# To match the rest of code, we define the residual as the mismatch
r = (f - rs.predict(Y)[0]).flatten()
hist['residual'].append(r)
hist['inner_steps'].append(log['final_values']['iterations'])
if disp:
print "iter %3d\t |r| : %10.10e" % (i, np.linalg.norm(res))
# Update iterators
U0 = U1
i += 1
# Store data
if i == maxiter:
exitflag = 1
else:
exitflag = 0
if history:
return U0, hist
else:
return U0
def spatial_envelope(X_env, Y_env, si, theta, u, thershold):
#const:
#n,p,r
#H,G
#beta_MLE
#si: matrix of loacation
n, p, r = X_env.shape[0], X_env.shape[1], Y_env.shape[1]
H = Y_env - np.kron(
np.mean(Y_env, axis=0).reshape(1, r),
np.repeat(1, n).reshape(n, 1))
G = X_env - np.kron(
np.mean(X_env, axis=0).reshape(1, p),
np.repeat(1, n).reshape(n, 1))
linear_model = LinearRegression().fit(X_env, Y_env)
err = Y_env - linear_model.predict(X_env)
beta_MLE = linear_model.coef_
# changable
# judge, iter_count, err_count, theta
# V0_hat, V1_hat, PV0_hat, PV1_hat
# Sigma_Y, Sigma_res
# rho_h_theta
Sigma_res = np.cov(err.T)
Sigma_Y = np.cov(Y_env.T)
judge = True
iter_count = 0
cal_thershold, min_thershold = thershold, thershold
prot = 1
err_count = 0
while judge:
try:
if err_count > 10:
print("Start new")
theta = np.random.uniform(0, 0.5, 2)
err_count = 0
# Step1: Optimize on Gamma to get V0,V1,PV0,PV1
def cost(Gamma):
X = np.matmul(Gamma, Gamma.T)
out = -np.log(
np.linalg.det(
np.matmul(np.matmul(X, Sigma_res), X) +
np.matmul(np.matmul(np.eye(r) - X, Sigma_Y),
np.eye(r) - X)))
return (np.array(out))
manifold = Grassmann(r, u)
#manifold = Stiefel(r,u)
problem = Problem(manifold=manifold, cost=cost, verbosity=0)
solver = SteepestDescent()
Gamma = solver.solve(problem)
PV1_hat = np.matmul(Gamma, Gamma.T)
PV0_hat = np.eye(r) - PV1_hat
V1_hat = np.matmul(np.matmul(PV1_hat, Sigma_Y), PV1_hat)
V0_hat = np.matmul(np.matmul(PV1_hat, Sigma_res), PV1_hat)
# Step2: Optimize on theta
def theta_fun(theta):
rho_h_theta = np.array(rho(si, theta))
item1 = np.matmul(
sqrtm(np.linalg.inv(rho_h_theta).real).real, G)
project = lambda x: np.eye(n) - np.matmul(
np.matmul(x,
np.linalg.inv(np.matmul(x.T, x)).real), x.T)
item2 = np.matmul(
np.matmul(project(item1),
sqrtm(np.linalg.inv(rho_h_theta).real).real), H)
item3 = np.matmul(
np.matmul(item2,
np.linalg.pinv(V1_hat).real), item2.T)
item4 = np.matmul(
sqrtm(np.linalg.inv(rho_h_theta).real).real, H)
item5 = np.matmul(
np.matmul(item4,
np.linalg.pinv(V0_hat).real), item4.T)
loss = r * np.linalg.det(rho_h_theta) + 0.5 * np.trace(item3 +
item5)
return (loss)
# print("Theta: {}".format(theta))
opt_res = minimize(theta_fun, theta, method="BFGS")
# print("Pass")
weight = max(min(1, 1 / cal_thershold),
(thershold / prot)**(1 - 1 / (iter_count + 1)))
theta_opt = np.abs(np.array(opt_res.x))
theta_new = (1 - weight) * theta + weight * theta_opt
theta = theta_new
# theta = np.array(opt_res.x)
# Step3 update Sigma_Y, Sigma_Res based on theta
rho_h_theta = np.array(rho(si, theta))
term1 = np.matmul(np.matmul(H.T,
np.linalg.inv(rho_h_theta).real), H)
term2 = np.matmul(np.matmul(G.T,
np.linalg.inv(rho_h_theta).real), H)
term3 = np.matmul(np.matmul(G.T,
np.linalg.inv(rho_h_theta).real), G)
Sigma_Y = term1
Sigma_res = term1 - np.matmul(
np.matmul(term2.T,
np.linalg.inv(term3).real), term2)
if iter_count == 0:
iter_count += 1
oldV0_hat, oldV1_hat, old_theta = V0_hat, V1_hat, theta
continue
# print("Before thershold")
cal_thershold = np.sum((oldV1_hat - V1_hat)**2) + np.sum(
(oldV0_hat - V0_hat)**2) + np.sum((old_theta - theta)**2)
print("Gap: {}, Theta: {}, weight: {}".format(
cal_thershold, theta, weight))
if cal_thershold < thershold:
judge = False
min_thershold = min(min_thershold, cal_thershold)
prot = cal_thershold / min_thershold
oldV0_hat, oldV1_hat, old_theta = V0_hat, V1_hat, theta
iter_count += 1
except:
err_count += 1
theta = theta + np.array([
randint(-10, 10) * thershold * prot,
randint(-10, 10) * thershold * prot
])
X_env = X_env + np.random.normal(0, 1e-6, n * p).reshape(n, p)
Y_env = Y_env + np.random.normal(0, 1e-6, n * r).reshape(n, r)
continue
beta_final = np.matmul(PV1_hat, beta_MLE)
Y_bar = np.mean(Y_env, axis=0)
X_bar = np.mean(X_env, axis=0)
alpha_final = Y_bar - np.matmul(X_bar, beta_final.T)
output = (alpha_final.reshape(1, r), beta_final.reshape(p, r))
# print("stop, iter = {}".format(iter_count+err_count))
return (output)
class TestMultiGrassmannManifold(unittest.TestCase):
def setUp(self):
self.m = m = 5
self.n = n = 2
self.k = k = 3
self.man = Grassmann(m, n, k=k)
self.proj = lambda x, u: u - npa.dot(x, npa.dot(x.T, u))
def test_dim(self):
assert self.man.dim == self.k * (self.m * self.n - self.n ** 2)
def test_typicaldist(self):
np_testing.assert_almost_equal(self.man.typicaldist,
np.sqrt(self.n * self.k))
def test_dist(self):
x = self.man.rand()
y = self.man.rand()
np_testing.assert_almost_equal(self.man.dist(x, y),
self.man.norm(x, self.man.log(x, y)))
def test_inner(self):
X = self.man.rand()
A = self.man.randvec(X)
B = self.man.randvec(X)
np_testing.assert_allclose(np.sum(A * B), self.man.inner(X, A, B))
def test_proj(self):
# Construct a random point X on the manifold.
X = self.man.rand()
# Construct a vector H in the ambient space.
H = rnd.randn(self.k, self.m, self.n)
# Compare the projections.
Hproj = H - multiprod(X, multiprod(multitransp(X), H))
np_testing.assert_allclose(Hproj, self.man.proj(X, H))
def test_retr(self):
# Test that the result is on the manifold and that for small
# tangent vectors it has little effect.
x = self.man.rand()
u = self.man.randvec(x)
xretru = self.man.retr(x, u)
np_testing.assert_allclose(multiprod(multitransp(xretru), xretru),
multieye(self.k, self.n),
atol=1e-10)
u = u * 1e-6
xretru = self.man.retr(x, u)
np_testing.assert_allclose(xretru, x + u)
# def test_egrad2rgrad(self):
def test_norm(self):
x = self.man.rand()
u = self.man.randvec(x)
np_testing.assert_almost_equal(self.man.norm(x, u), la.norm(u))
def test_rand(self):
# Just make sure that things generated are on the manifold and that
# if you generate two they are not equal.
X = self.man.rand()
np_testing.assert_allclose(multiprod(multitransp(X), X),
multieye(self.k, self.n), atol=1e-10)
Y = self.man.rand()
assert la.norm(X - Y) > 1e-6
def test_randvec(self):
# Make sure things generated are in tangent space and if you generate
# two then they are not equal.
X = self.man.rand()
U = self.man.randvec(X)
np_testing.assert_allclose(multisym(multiprod(multitransp(X), U)),
np.zeros((self.k, self.n, self.n)),
atol=1e-10)
V = self.man.randvec(X)
assert la.norm(U - V) > 1e-6
# def test_transp(self):
def test_exp_log_inverse(self):
s = self.man
x = s.rand()
y = s.rand()
u = s.log(x, y)
z = s.exp(x, u)
np_testing.assert_almost_equal(0, self.man.dist(y, z))
def test_log_exp_inverse(self):
s = self.man
x = s.rand()
u = s.randvec(x)
y = s.exp(x, u)
v = s.log(x, y)
# Check that the manifold difference between the tangent vectors u and
# v is 0
np_testing.assert_almost_equal(0, self.man.norm(x, u - v))
def PNG(X, log=True, verbosity = 1):
# Assuming X consists of N points on Gr(p, n), p < n
# options:
# log: print projection info
# return an N x p(n-p) score array
N, n, p = X.shape
cpx = np.iscomplex(X).any() # true if X is complex-valued
scores = np.zeros((N,int(p*(n-p))), dtype = X.dtype)
scores[:] = np.NaN
X_old = X.copy()
# Gr(p, n) -> Gr(p, n-1) -> ... -> Gr(p, p+1)
for i in range(n-1, p, -1):
if log:
print(f'Gr({p}, {i+1}) -> Gr({p}, {i})')
#X_new, A, B = NG_dr(X_old, i, verbosity)
X_new, A, A_perp, b = NG_dr1(X_old, verbosity)
#A_perp = ortho_complement(A)[:,0]
AAT = np.matmul(A, A.conj().T)
#IAATB = np.matmul(np.eye(X_old.shape[1]) - AAT, B)
A_perpBT = np.matmul(A_perp, b.T)
#X_new_embedded = np.array([np.linalg.qr(np.matmul(A, X_new[i]) + IAATB)[0] for i in range(N)])
X_new_embedded = np.array([np.linalg.qr(np.matmul(A, X_new[i]) + A_perpBT)[0] for i in range(N)])
# compute scores
if cpx:
gr = ComplexGrassmann(X_old.shape[1], X_old.shape[2])
else:
gr = Grassmann(X_old.shape[1], X_old.shape[2])
for j in range(N):
scores[j,((n-i-1)*p):(n-i)*p] = gr.dist(X_old[j], X_new_embedded[j]) * \
np.matmul(X_old[j].conj().transpose(), A_perp)[:,0]
X_old = X_new
if p > 1:
# Gr(p, p+1) -> Gr(1, p+1)
X_new = np.zeros((N, p+1, 1), dtype=X_old.dtype)
if log:
print(f'Gr({p}, {p+1}) -> Gr(1, {p+1})')
for i in range(N):
X_new[i] = ortho_complement(X_old[i])
X_old = X_new
# Gr(1, p+1) -> ... -> Gr(1,2)
for i in range(p, 1, -1):
if log:
print(f'Gr(1, {i+1}) -> Gr(1, {i})')
#X_new, A, B = NG_dr(X_old, i, verbosity)
X_new, A, A_perp, b = NG_dr1(X_old, verbosity)
#A_perp = ortho_complement(A)[:,0]
AAT = np.matmul(A, A.conj().T)
#IAATB = np.matmul(np.eye(X_old.shape[1]) - AAT, B)
A_perpBT = np.matmul(A_perp, b.T)
#X_new_embedded = np.array([np.linalg.qr(np.matmul(A, X_new[i]) + IAATB)[0] for i in range(N)])
X_new_embedded = np.array([np.linalg.qr(np.matmul(A, X_new[i]) + A_perpBT)[0] for i in range(N)])
# compute scores
if cpx:
gr = ComplexGrassmann(X_old.shape[1], X_old.shape[2])
else:
gr = Grassmann(X_old.shape[1], X_old.shape[2])
for j in range(N):
scores[j,(n-p)*p-i] = gr.dist(X_old[j], X_new_embedded[j]) * \
np.matmul(X_old[j].conj().transpose(), A_perp)
X_old = X_new
# Gr(1,2) -> NGM
if log:
print('Gr(1, 2) -> NGM')
if cpx:
gr = ComplexGrassmann(2,1)
else:
gr = Grassmann(2,1)
NGM = compute_centroid(gr, X_new)
v_0 = gr.log(NGM, X_new[0])
v_0 = v_0/np.linalg.norm(v_0)
for j in range(N):
v = gr.log(NGM, X_new[j])/v_0
scores[j, (n-p)*p-1] = v[0] # signed distance
return scores[:,::-1]
