def test_precond_LinearLeastSquares(self):
n = 5
_A = np.eye(n) + 0.01 * util.randn([n, n])
A = linop.MatMul([n, 1], _A)
x = util.randn([n, 1])
y = A(x)
x_lstsq = np.linalg.lstsq(_A, y, rcond=-1)[0]
p = 1 / (np.sum(abs(_A)**2, axis=0).reshape([n, 1]))
P = linop.Multiply([n, 1], p)
x_rec = app.LinearLeastSquares(A, y, show_pbar=False).run()
npt.assert_allclose(x_rec, x_lstsq, atol=1e-3)
alpha = 1 / app.MaxEig(P * A.H * A, show_pbar=False).run()
x_rec = app.LinearLeastSquares(A,
y,
solver='GradientMethod',
alpha=alpha,
max_power_iter=100,
max_iter=1000,
show_pbar=False).run()
npt.assert_allclose(x_rec, x_lstsq, atol=1e-3)
tau = p
x_rec = app.LinearLeastSquares(A,
y,
solver='PrimalDualHybridGradient',
max_iter=1000,
tau=tau,
show_pbar=False).run()
npt.assert_allclose(x_rec, x_lstsq, atol=1e-3)
def test_Multiply(self):
# Test scalar
ishape = [2]
mult = 1.1
A = linop.Multiply(ishape, mult)
self.check_linop_adjoint(A)
self.check_linop_normal(A)
self.check_linop_linear(A)
self.check_linop_pickleable(A)
x = np.array([1.0, 2.0], np.complex)
y = np.array([1.1, 2.2], np.complex)
npt.assert_allclose(A * x, y)
# Test simple
ishape = [2]
mult = np.array([1.0, 2.0])
A = linop.Multiply(ishape, mult)
self.check_linop_adjoint(A)
self.check_linop_normal(A)
self.check_linop_linear(A)
self.check_linop_pickleable(A)
x = np.array([1.0, 2.0], np.complex)
y = np.array([1.0, 4.0], np.complex)
npt.assert_allclose(A * x, y)
# Test broadcasting
ishape = [2]
mult = np.array([[1.0, 2.0], [3.0, 4.0]])
A = linop.Multiply(ishape, mult)
self.check_linop_adjoint(A)
self.check_linop_normal(A)
self.check_linop_linear(A)
self.check_linop_pickleable(A)
x = np.array([1.0, 2.0], np.complex)
y = np.array([[1.0, 4.0], [3.0, 8.0]], np.complex)
npt.assert_allclose(A * x, y)
def test_precond_LinearLeastSquares(self):
n = 5
mat = np.eye(n) + 0.1 * util.randn([n, n])
A = linop.MatMul([n, 1], mat)
x = util.randn([n, 1])
y = A(x)
x_lstsq = np.linalg.lstsq(mat, y, rcond=-1)[0]
p = 1 / (np.sum(abs(mat)**2, axis=0).reshape([n, 1]))
P = linop.Multiply([n, 1], p)
x_rec = app.LinearLeastSquares(A, y).run()
npt.assert_allclose(x_rec, x_lstsq)
alpha = p / app.MaxEig(P * A.H * A).run()
x_rec = app.LinearLeastSquares(A, y, alg_name='GradientMethod',
max_iter=1000, alpha=alpha).run()
npt.assert_allclose(x_rec, x_lstsq)
tau = p
x_rec = app.LinearLeastSquares(A, y, alg_name='PrimalDualHybridGradient',
max_iter=1000, tau=tau).run()
npt.assert_allclose(x_rec, x_lstsq)
def _get_PrimalDualHybridGradient(self):
with self.y_device:
y = -self.y
A = self.A
if self.proxg is None:
proxg = prox.NoOp(self.x.shape)
else:
proxg = self.proxg
if self.lamda > 0:
def gradh(x):
with backend.get_device(self.x):
gradh_x = 0
if self.lamda > 0:
if self.z is None:
gradh_x += self.lamda * x
else:
gradh_x += self.lamda * (x - self.z)
return gradh_x
gamma_primal = self.lamda
else:
gradh = None
gamma_primal = 0
if self.G is None:
proxfc = prox.L2Reg(y.shape, 1, y=y)
gamma_dual = 1
else:
A = linop.Vstack([A, self.G])
proxf1c = prox.L2Reg(self.y.shape, 1, y=y)
proxf2c = prox.Conj(self.proxg)
proxfc = prox.Stack([proxf1c, proxf2c])
proxg = prox.NoOp(self.x.shape)
gamma_dual = 0
if self.tau is None:
if self.sigma is None:
self.sigma = 1
S = linop.Multiply(A.oshape, self.sigma)
AHA = A.H * S * A
max_eig = MaxEig(AHA,
dtype=self.x.dtype,
device=self.x_device,
max_iter=self.max_power_iter,
show_pbar=self.show_pbar).run()
self.tau = 1 / (max_eig + self.lamda)
else:
T = linop.Multiply(A.ishape, self.tau)
AAH = A * T * A.H
max_eig = MaxEig(AAH,
dtype=self.x.dtype,
device=self.x_device,
max_iter=self.max_power_iter,
show_pbar=self.show_pbar).run()
self.sigma = 1 / max_eig
with self.y_device:
u = self.y_device.xp.zeros(A.oshape, dtype=self.y.dtype)
self.alg = PrimalDualHybridGradient(proxfc,
proxg,
A,
A.H,
self.x,
u,
self.tau,
self.sigma,
gamma_primal=gamma_primal,
gamma_dual=gamma_dual,
gradh=gradh,
max_iter=self.max_iter)
def _get_PrimalDualHybridGradient(self):
with self.y_device:
A = self.A
if self.lamda > 0:
gamma_primal = self.lamda
proxg = prox.L2Reg(self.x.shape,
self.lamda,
y=self.z,
proxh=self.proxg)
else:
gamma_primal = 0
if self.proxg is None:
proxg = prox.NoOp(self.x.shape)
else:
proxg = self.proxg
if self.G is None:
proxfc = prox.L2Reg(self.y.shape, 1, y=-self.y)
gamma_dual = 1
else:
A = linop.Vstack([A, self.G])
proxf1c = prox.L2Reg(self.y.shape, 1, y=-self.y)
proxf2c = prox.Conj(proxg)
proxfc = prox.Stack([proxf1c, proxf2c])
proxg = prox.NoOp(self.x.shape)
gamma_dual = 0
if self.tau is None:
if self.sigma is None:
self.sigma = 1
S = linop.Multiply(A.oshape, self.sigma)
AHA = A.H * S * A
max_eig = MaxEig(AHA,
dtype=self.x.dtype,
device=self.x_device,
max_iter=self.max_power_iter,
show_pbar=self.show_pbar).run()
self.tau = 1 / max_eig
elif self.sigma is None:
T = linop.Multiply(A.ishape, self.tau)
AAH = A * T * A.H
max_eig = MaxEig(AAH,
dtype=self.x.dtype,
device=self.x_device,
max_iter=self.max_power_iter,
show_pbar=self.show_pbar).run()
self.sigma = 1 / max_eig
with self.y_device:
u = self.y_device.xp.zeros(A.oshape, dtype=self.y.dtype)
self.alg = PrimalDualHybridGradient(proxfc,
proxg,
A,
A.H,
self.x,
u,
self.tau,
self.sigma,
gamma_primal=gamma_primal,
gamma_dual=gamma_dual,
max_iter=self.max_iter)