def testMinrealBrute(self):
for n, m, p in permutations(range(1,6), 3):
s = matlab.rss(n, p, m)
sr = s.minreal()
if s.states > sr.states:
self.nreductions += 1
else:
np.testing.assert_array_almost_equal(
np.sort(eigvals(s.A)), np.sort(eigvals(sr.A)))
for i in range(m):
for j in range(p):
ht1 = matlab.tf(
matlab.ss(s.A, s.B[:,i], s.C[j,:], s.D[j,i]))
ht2 = matlab.tf(
matlab.ss(sr.A, sr.B[:,i], sr.C[j,:], sr.D[j,i]))
try:
self.assert_numden_almost_equal(
ht1.num[0][0], ht2.num[0][0],
ht1.den[0][0], ht2.den[0][0])
except Exception as e:
# for larger systems, the tf minreal's
# the original rss, but not the balanced one
if n < 6:
raise e
self.assertEqual(self.nreductions, 2)
def modularity_spectrum(G):
"""Return eigenvalues of the modularity matrix of G.
Parameters
----------
G : Graph
A NetworkX Graph or DiGraph
Returns
-------
evals : NumPy array
Eigenvalues
See Also
--------
modularity_matrix
References
----------
.. [1] M. E. J. Newman, "Modularity and community structure in networks",
Proc. Natl. Acad. Sci. USA, vol. 103, pp. 8577-8582, 2006.
"""
from scipy.linalg import eigvals
if G.is_directed():
return eigvals(nx.directed_modularity_matrix(G))
else:
return eigvals(nx.modularity_matrix(G))
def format_eig_svd():
def format_cplx(z):
if z.imag < 1e-300:
return '{0:.4f}'.format(z.real)
return '{0:.4f}+{1:.4f}i'.format(z.real, z.imag)
eig12 = sp.eigvals(generate_matrix(12))
svd12 = sp.svdvals(generate_matrix(12))
eig25 = sp.eigvals(generate_matrix(25))
svd25 = sp.svdvals(generate_matrix(25))
result12 = r'\begin{tabular}{cc}' + '\n'
result12 += r' Eigenvalues&Singular values\\' + '\n'
result12 += ' \\hline\n'
result25 = copy.copy(result12)
for k in range(25):
if k < 12:
result12 += r' ${0}$&${1:.4f}$\\'.format(format_cplx(eig12[k]), svd12[k]) + '\n'
result25 += r' ${0}$&${1:.4f}$\\'.format(format_cplx(eig25[k]), svd25[k]) + '\n'
result12 += '\\end{tabular}\n'
result25 += '\\end{tabular}\n'
print(result12)
print(result25)
def test_dare(self):
A = matrix([[-0.6, 0],[-0.1, -0.4]])
Q = matrix([[2, 1],[1, 0]])
B = matrix([[2, 1],[0, 1]])
R = matrix([[1, 0],[0, 1]])
X,L,G = dare(A,B,Q,R)
# print("The solution obtained is", X)
assert_array_almost_equal(
A.T * X * A - X -
A.T * X * B * solve(B.T * X * B + R, B.T * X * A) + Q, zeros((2,2)))
assert_array_almost_equal(solve(B.T * X * B + R, B.T * X * A), G)
# check for stable closed loop
lam = eigvals(A - B * G)
assert_array_less(abs(lam), 1.0)
A = matrix([[1, 0],[-1, 1]])
Q = matrix([[0, 1],[1, 1]])
B = matrix([[1],[0]])
R = 2
X,L,G = dare(A,B,Q,R)
# print("The solution obtained is", X)
assert_array_almost_equal(
A.T * X * A - X -
A.T * X * B * solve(B.T * X * B + R, B.T * X * A) + Q, zeros((2,2)))
assert_array_almost_equal(B.T * X * A / (B.T * X * B + R), G)
# check for stable closed loop
lam = eigvals(A - B * G)
assert_array_less(abs(lam), 1.0)
def get_graph_props(g):
travgl = g.transitivity_avglocal_undirected()
tru = g.transitivity_undirected()
d = g.diameter()
asd = g.assortativity_degree()
apl = g.average_path_length()
omega = g.omega()
density = g.density()
maxd = g.maxdegree()
medd = np.median(g.degree())
plaw = ig.power_law_fit(g.degree())
spnorm = max(np.abs(spl.eigvals(g.get_adjacency().data)))
leigs = spl.eigvals(g.laplacian())
algc = abs(sorted([e for e in leigs if e > 1e-10])[1])
return [travgl, # avg. local transitivity
tru, # global transitivity
d, # diameter
asd, # degree assortativity
apl, # avg. path length
omega, # max. clique
density,
maxd, # max. degree
medd, # median degree
plaw.alpha, # power law exponent
spnorm, # largest eigenvalue of adj. matrix
algc, # 2nd smallest non-zero eigenvalue of laplacian
]
def ps_scatter_plot(A, epsilon=.001, num_pts=20):
n = A.shape[0]
eigs = np.empty((num_pts+1,n),dtype=complex)
for i in xrange(1,num_pts+1):
E = np.random.random((n,n))
E *= epsilon/la.norm(E)
es = la.eigvals(A+E)
eigs[i,:] = es
plt.plot(np.real(eigs[i]),np.imag(eigs[i]),'b*')
eigs[0] = la.eigvals(A.todense())
plt.plot(np.real(eigs[0]),np.imag(eigs[0]),'r*')
plt.show()
return eigs
def computeAbsoluteLimitingLinearCoefficient(n,multiplyO,multiplyN,multiplyL,multiplyR): # {{{
if True: # n <= 3:
matrix = []
for i in range(n):
matrix.append(multiplyO(array([0]*i+[1]+[0]*(n-1-i))))
matrix = array(matrix)
evals = eigvals(matrix)
lam = evals[argmax(abs(evals))]
tmatrix = matrix-lam*identity(n)
ovecs = svd(dot(tmatrix,tmatrix))[-1][-2:]
assert ovecs.shape == (2,n)
else:
ovals, ovecs = eigs(LinearOperator((n,n),matvec=multiplyO),k=2,which='LM',ncv=9)
ovecs = ovecs.transpose()
Omatrix = zeros((2,2),dtype=complex128)
for i in range(2):
for j in range(2):
Omatrix[i,j] = dot(ovecs[i].conj(),multiplyO(ovecs[j]))
numerator = sqrt(trace(dot(Omatrix.transpose().conj(),Omatrix))-2)
lnvecs = multiplyL(ovecs)
rnvecs = multiplyR(ovecs)
Nmatrix = zeros((2,2),dtype=complex128)
for i in range(2):
for j in range(2):
Nmatrix[i,j] = dot(lnvecs[i].conj(),multiplyN(rnvecs[j]))
denominator = sqrt(trace(dot(Nmatrix.transpose().conj(),Nmatrix)))
return numerator/denominator
def bands(self, k):
"""
Compute the band structure in the first Bloch wavevector k = [-pi/a, pi/a]
"""
# onsite energies
onsite = self.onsite
# consider the case where hop_inter and hop_intra are different
# the intra-cell hopping term \Sum_i a_i^\dag b_i = \Sum_k a_k^\dag b_k e^{ik(rb - ra)}
# the inter-cell hopping term \Sum_j b_j^\dag a_{j+1} = \Sum_k b_k^\dag a_k e^{ik(ra - rb)}
hop_intra = self.hop_intra
hop_inter = self.hop_inter
Norbs = self.Norbs
r = self.r
a = self.a
# constuct the H_k matrix, that is the Hamiltonian expressed in terms of spacial Fourier space
# H = (a_k, b_k)^\dag H(k) (a_k, b_k)^T
H = np.zeros((Norbs, Norbs), dtype=np.complex128)
# onsite energy
for i in range(Norbs): H[i,i] = onsite[i]
# hopping parameters
for i in range(Norbs):
for j in range(i+1, Norbs):
H[i,j] = hop_intra[i,j] * np.exp(-1j * k * (r[i] - r[j])) + \
hop_inter[i,j] * np.exp(-1j * k *(a + r[i] - r[j]))
H[j,i] = np.conj(H[i,j])
eigvals = linalg.eigvals(H)
return eigvals
def _default_response_times(A, n):
"""Compute a reasonable set of time samples for the response time.
This function is used by `impulse`, `impulse2`, `step` and `step2`
to compute the response time when the `T` argument to the function
is None.
Parameters
----------
A : ndarray
The system matrix, which is square.
n : int
The number of time samples to generate.
Returns
-------
t : ndarray
The 1-D array of length `n` of time samples at which the response
is to be computed.
"""
# Create a reasonable time interval.
# TODO: This could use some more work.
# For example, what is expected when the system is unstable?
vals = linalg.eigvals(A)
r = min(abs(real(vals)))
if r == 0.0:
r = 1.0
tc = 1.0 / r
t = linspace(0.0, 7 * tc, n)
return t
def Energy_condensate_full(Q, F1, x, y, H, mu, kappa, Ns) :
if Q==0 and F1 ==0 :
return 1e14
m = find_minimum(Q, F1, mu, kappa, Ns)
if m[0] < H/2 :
return 1e14
result = 0
for n1 in range(Ns) :
for n2 in range(Ns) :
M, dim = HamiltonianMatrix(n1, n2, Q, F1, 0, H, mu, kappa, Ns, 'T1')
B = np.identity(dim)
B[dim/2:dim, dim/2:dim] = -np.identity(dim/2)
eig = np.absolute(np.real(lin.eigvals(np.dot(B,M))))
result += sum(eig)/2
vec = [x[Ns * n1 + n2], np.conjugate(y[Ns * ((Ns - n1) % Ns) + (Ns - n2) % Ns])]
result += np.dot(vec, np.dot(np.conj(vec).T, M))
return result - 3 * Ns ** 2 * (np.abs(F1)**2 - np.abs(Q)**2)/2 - Ns**2 * mu*(1. + kappa) + Ns * H
def _default_response_frequencies(A, n):
"""Compute a reasonable set of frequency points for bode plot.
This function is used by `bode` to compute the frequency points (in rad/s)
when the `w` argument to the function is None.
Parameters
----------
A : ndarray
The system matrix, which is square.
n : int
The number of time samples to generate.
Returns
-------
w : ndarray
The 1-D array of length `n` of frequency samples (in rad/s) at which
the response is to be computed.
"""
vals = linalg.eigvals(A)
# Remove poles at 0 because they don't help us determine an interesting
# frequency range. (And if we pass a 0 to log10() below we will crash.)
poles = [pole for pole in vals if pole != 0]
# If there are no non-zero poles, just hardcode something.
if len(poles) == 0:
minpole = 1
maxpole = 1
else:
minpole = min(abs(real(poles)))
maxpole = max(abs(real(poles)))
# A reasonable frequency range is two orders of magnitude before the
# minimum pole (slowest) and two orders of magnitude after the maximum pole
# (fastest).
w = numpy.logspace(numpy.log10(minpole) - 2, numpy.log10(maxpole) + 2, n)
return w
def ar_model_check_stable(A):
"""check if this AR model is stable
:Parameters:
A : ndarray
The coefficient matrix of the model
"""
# inits and checks
m, p = A.shape
p /= m
if p != round(p):
raise ValueError('bad inputs!')
# check for stable model
A1 = N.concatenate((
A,
N.concatenate((
N.eye((p - 1) * m),
N.zeros(((p - 1) * m, m))
), axis=1)
))
lambdas = NL.eigvals(A1)
rval = True
if (N.absolute(lambdas) > 1).any():
rval = False
del A1, lambdas
return rval
def test_simple_tr(self):
a = array([[1,2,3],[1,2,3],[2,5,6]],'d')
a = transpose(a).copy()
a = transpose(a)
w = eigvals(a)
exact_w = [(9+sqrt(93))/2,0,(9-sqrt(93))/2]
assert_array_almost_equal(w,exact_w)
def test_simple_complex(self):
a = [[1,2,3],[1,2,3],[2,5,6+1j]]
w = eigvals(a)
exact_w = [(9+1j+sqrt(92+6j))/2,
0,
(9+1j-sqrt(92+6j))/2]
assert_array_almost_equal(w,exact_w)
def adjacency_spectrum(G, weight='weight'):
"""Return eigenvalues of the adjacency matrix of G.
Parameters
----------
G : graph
A NetworkX graph
weight : string or None, optional (default='weight')
The edge data key used to compute each value in the matrix.
If None, then each edge has weight 1.
Returns
-------
evals : NumPy array
Eigenvalues
Notes
-----
For MultiGraph/MultiDiGraph, the edges weights are summed.
See to_numpy_matrix for other options.
See Also
--------
adjacency_matrix
"""
from scipy.linalg import eigvals
return eigvals(nx.adjacency_matrix(G,weight=weight).todense())
def test_timescales(self):
P_dense=self.bdc.transition_matrix()
P=self.bdc.transition_matrix_sparse()
ev=eigvals(P_dense)
"""Sort with decreasing magnitude"""
ev=ev[np.argsort(np.abs(ev))[::-1]]
ts=-1.0/np.log(np.abs(ev))
"""k=None"""
with self.assertRaises(ValueError):
tsn=timescales(P)
"""k is not None"""
tsn=timescales(P, k=self.k)
self.assertTrue(np.allclose(ts[1:self.k], tsn[1:]))
"""k is not None, ncv is not None"""
tsn=timescales(P, k=self.k, ncv=self.ncv)
self.assertTrue(np.allclose(ts[1:self.k], tsn[1:]))
"""tau=7"""
"""k is not None"""
tsn=timescales(P, k=self.k, tau=7)
self.assertTrue(np.allclose(7*ts[1:self.k], tsn[1:]))
def set_aw(sys,poles):
"""Divide in controller in input and feedback part
for anti-windup
Usage
=====
[sys_in,sys_fbk]=set_aw(sys,poles)
Inputs
------
sys: controller
poles : poles for the anti-windup filter
Outputs
-------
sys_in, sys_fbk: controller in input and feedback part
"""
sys=ss(sys);
den_old=poly(eigvals(sys.A))
den = poly(poles)
tmp= tf(den_old,den,sys.Tsamp)
tmpss=tf2ss(tmp)
sys_in=ss(tmp*sys)
sys_in.Tsamp=sys.Tsamp
sys_fbk=ss(1-tmp)
sys_fbk.Tsamp=sys.Tsamp
return sys_in, sys_fbk
def _run_hamiltonian(verbose=True):
c = classicalHamiltonian()
if verbose:
print(c.potential(array([-0.5, 0.5])))
print(c.potential(array([-0.5, 0.0])))
print(c.potential(array([0.0, 0.0])))
xopt = optimize.fmin(c.potential, c.initialposition(), xtol=1e-10)
# Important to restrict the step in order to avoid the discontinutiy at
# x=[0,0]
# hessian = nd.Hessian(c.potential, step_max=1.0, step_nom=np.abs(xopt))
step = nd.MaxStepGenerator(step_max=2, step_ratio=4, num_steps=16)
hessian = nd.Hessian(c.potential, step=step, method='central',
full_output=True)
# hessian = algopy.Hessian(c.potential) # Does not work
# hessian = scientific.Hessian(c.potential) # does not work
H, info = hessian(xopt)
true_H = np.array([[5.23748385e-12, -2.61873829e-12],
[-2.61873829e-12, 5.23748385e-12]])
if verbose:
print(xopt)
print('H', H)
print('H-true_H', np.abs(H-true_H))
print('error_estimate', info.error_estimate)
eigenvalues = linalg.eigvals(H)
normal_modes = c.normal_modes(eigenvalues)
print('eigenvalues', eigenvalues)
print('normal_modes', normal_modes)
return H, info.error_estimate, true_H
def testMinreal(self, verbose=False):
"""Test a minreal model reduction"""
#A = [-2, 0.5, 0; 0.5, -0.3, 0; 0, 0, -0.1]
A = [[-2, 0.5, 0], [0.5, -0.3, 0], [0, 0, -0.1]]
#B = [0.3, -1.3; 0.1, 0; 1, 0]
B = [[0.3, -1.3], [0.1, 0.], [1.0, 0.0]]
#C = [0, 0.1, 0; -0.3, -0.2, 0]
C = [[0., 0.1, 0.0], [-0.3, -0.2, 0.0]]
#D = [0 -0.8; -0.3 0]
D = [[0., -0.8], [-0.3, 0.]]
# sys = ss(A, B, C, D)
sys = ss(A, B, C, D)
sysr = minreal(sys)
self.assertEqual(sysr.states, 2)
self.assertEqual(sysr.inputs, sys.inputs)
self.assertEqual(sysr.outputs, sys.outputs)
np.testing.assert_array_almost_equal(
eigvals(sysr.A), [-2.136154, -0.1638459])
s = tf([1, 0], [1])
h = (s+1)*(s+2.00000000001)/(s+2)/(s**2+s+1)
hm = minreal(h)
hr = (s+1)/(s**2+s+1)
np.testing.assert_array_almost_equal(hm.num[0][0], hr.num[0][0])
np.testing.assert_array_almost_equal(hm.den[0][0], hr.den[0][0])
def __init__(self, bb_ = (None,None), mumu_ = (None,None), met = (None,None), massT2=172.5**2, massW2=80.4**2, lv = utils.LorentzV ) :
U = np.diag([1,1,-1])
S = np.array([[-1, 0,met[0]],
[ 0,-1,met[1]],
[ 0, 0, 1]])
nus = utils.vessel()
nus.ellipse = tuple( self.Ellipse(b,mu,massT2,massW2) for b,mu in zip(bb_,mumu_) )
if any(e==None for e in nus.ellipse) : self.nunu_s = []; return
nus.ellipseT = tuple( np.vstack([e[:2],[0,0,1]]) for e in nus.ellipse )
nus.ellipseT_inv = tuple( np.linalg.inv(eT) for eT in nus.ellipseT )
nus.nT_inv = tuple( eT.dot(U.dot(eT.T)) for eT in nus.ellipseT )
nus.nT = tuple( np.linalg.inv(nTi) for nTi in nus.nT_inv )
nT_p = S.T.dot(nus.nT[1]).dot(S)
eig = next( e.real for e in LA.eigvals( nus.nT_inv[0].dot(nT_p),overwrite_a=True ) if not e.imag )
G = nT_p - eig * nus.nT[0]
nus.vs = [ ( nus.ellipse[0].dot(nus.ellipseT_inv[0]).dot(nuT),
nus.ellipse[1].dot(nus.ellipseT_inv[1]).dot(S.dot(nuT)))
for nuT in self.intersections( G, nus.nT[0] ) ]
if not nus.vs : nus.vs = [self.closestXY(nus.ellipse,met)]
self.nunu_s = [ (lv(),lv()) for _ in nus.vs ]
for (nu,n_),(vu,v_) in zip(self.nunu_s,nus.vs) :
nu.SetPxPyPzE(vu[0],vu[1],vu[2],0); nu.SetM(0)
n_.SetPxPyPzE(v_[0],v_[1],v_[2],0); n_.SetM(0)
self.nus = nus
self.bb_ = bb_
self.mumu_ = mumu_
self.met = met
def bb_step(sys,X0=None,Tf=None,Ts=0.001):
"""Plot the step response of the continous system sys
Call:
y=bb_step(sys [,Tf=final time] [,Ts=time step])
Parameters
----------
sys : Continous System in State Space form
X0: Initial state vector (not used yet)
Ts : sympling time
Tf : Final simulation time
Returns
-------
Nothing
"""
if Tf==None:
vals = eigvals(sys.A)
r = min(abs(real(vals)))
if r < 1e-10:
r = 0.1
Tf = 7.0 / r
sysd=c2d(sys,Ts)
dstep(sysd,Tf=Tf)
def eigenvalues(A, n):
"""
Return the eigenvalues of A in order from largest to smallest.
Parameters
----------
A : numpy.array with shape (nstates,nstates)
The matrix for which eigenvalues are to be computed.
n : int
The number of largest eigenvalues to return.
Examples
--------
Return all sorted eigenvalues.
>>> from bhmm.util import testsystems
>>> Tij = testsystems.generate_transition_matrix(nstates=3, reversible=True)
>>> ew_sorted = eigenvalues(Tij, 3)
Return largest eigenvalue.
>>> ew_sorted = eigenvalues(Tij, 1)
TODO
----
Replace this with a call to the EMMA method once we use EMMA as a dependency.
"""
v=linalg.eigvals(A).real
idx=(-v).argsort()[:n]
return v[idx]
def projection_shifts_init(A, E, B, shift_options):
"""Find starting shift parameters for low-rank ADI iteration using
Galerkin projection on spaces spanned by LR-ADI iterates.
See [PK16]_, pp. 92-95.
Parameters
----------
A
The |Operator| A from the corresponding Lyapunov equation.
E
The |Operator| E from the corresponding Lyapunov equation.
B
The |VectorArray| B from the corresponding Lyapunov equation.
shift_options
The shift options to use (see :func:`lyap_solver_options`).
Returns
-------
shifts
A |NumPy array| containing a set of stable shift parameters.
"""
for i in range(shift_options['init_maxiter']):
Q = gram_schmidt(B, atol=0, rtol=0)
shifts = spla.eigvals(A.apply2(Q, Q), E.apply2(Q, Q))
shifts = shifts[np.real(shifts) < 0]
if shifts.size == 0:
# use random subspace instead of span{B} (with same dimensions)
if shift_options['init_seed'] is not None:
np.random.seed(shift_options['init_seed'])
np.random.seed(np.random.random() + i)
B = B.space.make_array(np.random.rand(len(B), B.space.dim))
else:
return shifts
raise RuntimeError('Could not generate initial shifts for low-rank ADI iteration.')
def run_hamiltonian(hessian, verbose=True):
c = ClassicalHamiltonian()
xopt = optimize.fmin(c.potential, c.initialposition(), xtol=1e-10)
hessian.fun = c.potential
hessian.full_output = True
h, info = hessian(xopt)
true_h = np.array([[5.23748385e-12, -2.61873829e-12],
[-2.61873829e-12, 5.23748385e-12]])
eigenvalues = linalg.eigvals(h)
normal_modes = c.normal_modes(eigenvalues)
if verbose:
print(c.potential([-0.5, 0.5]))
print(c.potential([-0.5, 0.0]))
print(c.potential([0.0, 0.0]))
print(xopt)
print('h', h)
print('h-true_h', np.abs(h - true_h))
print('error_estimate', info.error_estimate)
print('eigenvalues', eigenvalues)
print('normal_modes', normal_modes)
return h, info.error_estimate, true_h
def _default_response_frequencies(A, n):
"""Compute a reasonable set of frequency points for bode plot.
This function is used by `bode` to compute the frequency points (in rad/s)
when the `w` argument to the function is None.
Parameters
----------
A : ndarray
The system matrix, which is square.
n : int
The number of time samples to generate.
Returns
-------
w : ndarray
The 1-D array of length `n` of frequency samples (in rad/s) at which
the response is to be computed.
"""
vals = linalg.eigvals(A)
minpole = min(abs(real(vals)))
maxpole = max(abs(real(vals)))
# A reasonable frequency range is two orders of magnitude before the
# minimum pole (slowest) and two orders of magnitude after the maximum pole
# (fastest).
w = numpy.logspace(numpy.log10(minpole) - 2, numpy.log10(maxpole) + 2, n)
return w
def step(system, X0=None, T=None, N=None):
"""Step response of continuous-time system.
Inputs:
system -- an instance of the LTI class or a tuple with 2, 3, or 4
elements representing (num, den), (zero, pole, gain), or
(A, B, C, D) representation of the system.
X0 -- (optional, default = 0) inital state-vector.
T -- (optional) time points (autocomputed if not given).
N -- (optional) number of time points to autocompute (100 if not given).
Ouptuts: (T, yout)
T -- output time points,
yout -- step response of system.
"""
if isinstance(system, lti):
sys = system
else:
sys = lti(*system)
if N is None:
N = 100
if T is None:
vals = linalg.eigvals(sys.A)
tc = 1.0/min(abs(real(vals)))
T = arange(0,7*tc,7*tc / float(N))
U = ones(T.shape, sys.A.dtype)
vals = lsim(sys, U, T, X0=X0)
return vals[0], vals[1]
def compare_eigen_methods():
""" timing of different eigensolver methods"""
import scipy.linalg as linalg
print '\n *** diagonalize a real symmetric band matrix by different methods ***\n'
mt=mytimer.create(10)
try:
N=float(sys.argv[1])
S=float(sys.argv[2])
except:
sys.exit('supply N S (command line arguments): matrix dimension N and and number of super-diagonals S ')
np.random.seed(1)
a=np.random.random((N,N))
ab=GMatrix(np.random.random((S+1,N)),storage='upper_banded')
mt[0].start('lapack symmetric upper banded')
print ab.store+'\n',ab.eigvals()[:5]
mt[0].stop()
a=ab.restore('full')
mt[1].start('lapack symmetric full')
print a.store+'\n',a.eigvals()[:5]
mt[1].stop()
print 'lingalg'
mt[2].start('linalg general')
print np.sort(linalg.eigvals(a.m).real)[:5]
mt[2].stop()
mytimer.table()
def __init__(self,para): self.parms = Parameters() self.parms.N = para.N self.parms.Nin = para.Nin self.parms.Nout= para.Nout self.parms.inp_sc= para.inp_sc self.parms.spectr_rad= para.spectr_rad self.parms.leak_rate= para.leak_rate self.parms.inpBias = para.inpBias self.parms.Pscaling = para.Pscaling self.parms.OutScaling = para.OutScaling self.parms.alpha = para.alpha self.parms.t1 = para.t1 self.parms.dt = para.dt self.parms.y_d = para.y_d self.P = np.eye(self.parms.N)*self.parms.Pscaling#100 self.inpBias = self.parms.inpBias * np.random.randn(self.parms.N,1) wtemp = np.random.randn(self.parms.N,self.parms.N) self.W = self.parms.spectr_rad*wtemp/max(abs(linalg.eigvals(wtemp))) self.V = np.random.randn(self.parms.N,self.parms.Nin)*np.dot(np.ones((self.parms.N,1)),self.parms.inp_sc) self.Woutp = np.random.randn(self.parms.Nout,self.parms.N) self.state_A = np.random.rand(self.parms.N,1)*2.-1. self.state_B = self.state_A self.orgstate = self.state_A
def z2_vanderbilt(h,nk=30,nt=100,nocc=None,full=False):
""" Calculate Z2 invariant according to Vanderbilt algorithm"""
out = [] # output list
path = np.linspace(0.,1.,nk) # set of kpoints
fo = open("WANNIER_CENTERS.OUT","w")
if full: ts = np.linspace(0.,1.0,nt,endpoint=False)
else: ts = np.linspace(0.,0.5,nt,endpoint=False)
wfall = [[occ_states2d(h,np.array([k,t,0.,])) for k in path] for t in ts]
# select a continuos gauge for the first wave
for it in range(len(ts)-1): # loop over ts
wfall[it+1][0] = smooth_gauge(wfall[it][0],wfall[it+1][0])
for it in range(len(ts)): # loop over t points
row = [] # empty list for this row
t = ts[it] # select the t point
wfs = wfall[it] # get set of waves
for i in range(len(wfs)-1):
wfs[i+1] = smooth_gauge(wfs[i],wfs[i+1]) # transform into a smooth gauge
# m = uij(wfs[i],wfs[i+1]) # matrix of wavefunctions
m = uij(wfs[0],wfs[len(wfs)-1]) # matrix of wavefunctions
evals = lg.eigvals(m) # eigenvalues of the rotation
x = np.angle(evals) # phase of the eigenvalues
fo.write(str(t)+" ") # write pumping variable
row.append(t) # store
for ix in x: # loop over phases
fo.write(str(ix)+" ")
row.append(ix) # store
fo.write("\n")
out.append(row) # store
fo.close()
return np.array(out).transpose() # transpose the map
def _run_hamiltonian(verbose=True):
c = classicalHamiltonian()
if verbose:
print(c.potential(array([-0.5, 0.5])))
print(c.potential(array([-0.5, 0.0])))
print(c.potential(array([0.0, 0.0])))
xopt = optimize.fmin(c.potential, c.initialposition(), xtol=1e-10)
hessian = nd.Hessian(c.potential)
H = hessian(xopt)
true_H = np.array([[5.23748385e-12, -2.61873829e-12],
[-2.61873829e-12, 5.23748385e-12]])
error_estimate = np.NAN
if verbose:
print(xopt)
print('H', H)
print('H-true_H', np.abs(H - true_H))
# print('error_estimate', info.error_estimate)
eigenvalues = linalg.eigvals(H)
normal_modes = c.normal_modes(eigenvalues)
print('eigenvalues', eigenvalues)
print('normal_modes', normal_modes)
return H, error_estimate, true_H
def find_zeros(self, pprint=False):
"""
Find the zeros and poles of a complex function (C->C) inside a closed curve.
input:
"""
# total multiplicity of zeros (number of zeros * order)
pol_unity = monicPolynomial([])
p_unity = pol_unity.f_polynomial()
residue = self.inner_prod(p_unity, p_unity)
N = int(round(residue.real))
accuracy = np.abs(N - residue)
if pprint: print('N =', N, ' (accuracy =', accuracy, ')')
# if N is zero
if N == 0:
n = 0
zeros = np.array([])
else:
# list of FOPs
phis = []
pols = []
phis.append(p_unity)
pols.append(pol_unity) # phi_0
# compute arithmetic mean of nodes
p_aux = monicPolynomial([0.]).f_polynomial()
mu = self.inner_prod(p_unity, p_aux) / N
if pprint: print('mu =', mu)
# append first polynomial
pol = monicPolynomial([-mu])
phis.append(pol.f_polynomial())
pols.append(pol) # phi_1
# if the algorithm quits after the first zero, it is mu
zeros = np.array([mu])
n = 1
# initialization
r = 1
t = 0
while r + t < N:
if pprint: print(str(r + t))
# naive criterion to check if phi_r+t+1 is regular
prod_aux, maxpsum = self.inner_prod(phis[-1],
phis[-1],
compute_maxpsum=True)
# compute eigenvalues of the next pencil
G, G1 = self.generalized_hankel_matrices(phis, pols)
eigv = la.eigvals(G1, G)
# print eigv
# check if these eigenvalues lie within the contour
if self.points_within_contour(eigv + mu):
# if np.abs(prod_aux)/maxpsum > eps_reg:
if pprint: print(str(r + t) + '.1')
# compute next FOP in the regular way
pol = monicPolynomial(eigv, coef_type='zeros')
phis.append(pol.f_polynomial())
pols.append(pol)
r += t + 1
t = 0
n = r
zeros = eigv + mu
else:
if pprint: print(str(r + t) + '.2')
c = npol.polyfromroots([mu])
pol = monicPolynomial(npol.polymul(c, pols[-1].coef),
coef_type='normal')
pols.append(pol)
phis.append(pol.f_polynomial())
t += 1
# check multiplicities
# constuct vandermonde system
if len(zeros) > 0:
A = np.vander(zeros).T[::-1, :]
b = np.array([
self.inner_prod(p_unity, lambda x, k=k: x**k) for k in range(n)
])
# solve the Vandermonde system
nu = la.solve(A, b)
nu = np.round(nu).real.astype(int)
sane = (np.sum(nu) == N)
else:
nu = np.array([])
sane = True
# for printing result
if pprint:
print('>>> Result of computation of zeros <<<')
print('number of zeros = ', n - len(np.where(nu == 0)[0]))
pstring = 'yes!' if sane == 1 else 'no!'
print('sane? ' + pstring)
for i, zero in enumerate(zeros):
print('zero #' + str(i + 1) + ' = ' + str(zero) +
' (multiplicity = ' + str(nu[i]) + ')')
print('')
# eliminate spurious zeros (the ones with zero multiplicity)
inds_ = np.argsort(zeros.real)
# inds = np.where(nu[inds_] > 0)[0]
if self.use_known_zeros:
self.global_zeros = np.concatenate(
(self.global_zeros, zeros[inds_][inds]))
self.global_zmultiplicities = np.concatenate(
(self.global_zmultiplicities, nu[inds_][inds]))
iglob = np.argsort(self.global_zeros.real)
self.global_zeros = self.global_zeros[iglob]
self.global_zmultiplicities = self.global_zmultiplicities[iglob]
return zeros[inds_], (n - len(np.where(nu == 0)[0]), nu[inds_], sane)
def QFIM_Gauss(R, dR, D, dD):
"""
Calculation of the SLD based quantum Fisher information (QFI) and quantum
Fisher information matrix (QFIM) with gaussian states.
Parameters
----------
> **R:** `array`
-- First-order moment.
> **dR:** `list`
-- Derivatives of the first-order moment on the unknown parameters to be
estimated. For example, dR[0] is the derivative vector on the first
parameter.
> **D:** `matrix`
-- Second-order moment.
> **dD:** `list`
-- Derivatives of the second-order moment on the unknown parameters to be
estimated. For example, dD[0] is the derivative vector on the first
parameter.
> **eps:** `float`
-- Machine epsilon.
Returns
----------
**QFI or QFIM with gaussian states:** `float or matrix`
-- For single parameter estimation (the length of drho is equal to one),
the output is QFI and for multiparameter estimation (the length of drho
is more than one), it returns QFIM.
"""
para_num = len(dR)
m = int(len(R) / 2)
QFIM_res = np.zeros([para_num, para_num])
C = np.array([[D[i][j] - R[i] * R[j] for j in range(2 * m)]
for i in range(2 * m)])
dC = [
np.array([[
dD[k][i][j] - dR[k][i] * R[j] - R[i] * dR[k][j]
for j in range(2 * m)
] for i in range(2 * m)]) for k in range(para_num)
]
C_sqrt = sqrtm(C)
J = np.kron([[0, 1], [-1, 0]], np.eye(m))
B = C_sqrt @ J @ C_sqrt
P = np.eye(2 * m)
P = np.vstack([P[:][::2], P[:][1::2]])
T, Q = schur(B)
vals = eigvals(B)
c = vals[::2].imag
Diag = np.diagflat(c**-0.5)
S = inv(J @ C_sqrt @ Q @ P @ np.kron([[0, 1], [-1, 0]], -Diag)).T @ P.T
sx = np.array([[0.0, 1.0], [1.0, 0.0]])
sy = np.array([[0.0, -1.0j], [1.0j, 0.0]])
sz = np.array([[1.0, 0.0], [0.0, -1.0]])
a_Gauss = [1j * sy, sz, np.eye(2), sx]
es = [[np.eye(1, m**2, m * i + j).reshape(m, m) for j in range(m)]
for i in range(m)]
As = [[np.kron(s, a_Gauss[i]) / np.sqrt(2) for s in es] for i in range(4)]
gs = [[[[np.trace(inv(S) @ dC @ inv(S.T) @ aa.T) for aa in a] for a in A]
for A in As] for dC in dC]
G = [
np.zeros((2 * m, 2 * m)).astype(np.longdouble) for _ in range(para_num)
]
for i in range(para_num):
for j in range(m):
for k in range(m):
for l in range(4):
G[i] += np.real(gs[i][l][j][k] / (4 * c[j] * c[k] +
(-1)**(l + 1)) *
inv(S.T) @ As[l][j][k] @ inv(S))
QFIM_res += np.real([[
np.trace(G[i] @ dC[j]) + dR[i] @ inv(C) @ dR[j]
for j in range(para_num)
] for i in range(para_num)])
if para_num == 1:
return QFIM_res[0][0]
else:
return QFIM_res
def time_eigvals(self, size, contig, module):
if module == 'numpy':
nl.eigvals(self.a)
else:
sl.eigvals(self.a)
def eigvalsh(a, UPLO="L", eigvals=[]):
val = la.eigvals(a)
val = np.sort(np.real(val))
if eigvals:
return val[eigvals[0]:eigvals[1] + 1]
return val
def is_stable(self, K):
stab = False
if np.amax(np.abs(LA.eigvals(self.a_cl(K)))) < (1.0 - 1.0e-6):
stab = True
return stab
# V
JAC[2*M-2, :] = concatenate((zeros(M), BTOP, zeros(4*M)))
JAC[2*M-1, :] = concatenate((zeros(M), BBOT, zeros(4*M)))
B = zeros((6*M, 6*M), dtype='complex')
B[:2*M, :2*M] = eye(2*M,2*M)
B[3*M:, 3*M:] = eye(3*M,3*M)
### BCs on RHS matrix
B[M-2, :] = 0
B[M-1, :] = 0
B[2*M-2, :] = 0
B[2*M-1, :] = 0
eigenvalues = linalg.eigvals(JAC, B)
eigenvalues = eigenvalues[~isnan(eigenvalues*conj(eigenvalues))]
eigenvalues = eigenvalues[~isinf(eigenvalues*conj(eigenvalues))]
eigarr = zeros((len(eigenvalues), 2))
eigarr[:,0] = real(eigenvalues)
eigarr[:,1] = imag(eigenvalues)
savetxt("eigs.txt", eigarr)
#actualDecayRate = amax(eigarr[:, 0])
actualDecayRate = -1.0
for i in range(len(eigarr[:,0])):
if eigarr[i,0] > 1.0:
continue
def matrix_matrix_best_mat(n, kA, kB, gammaB, no_trials):
samples_in_omega = 200
k = kA * kB
s = n - k
identity_part = np.identity((k), dtype=float)
DeltaB = int(np.round((s - 1) * (kB - 1) / (gammaB - 1 / kB)))
while DeltaB % kB != 0:
DeltaB = DeltaB + 1
z = int(DeltaB / kB + (s - 1) * (kB - 1))
workers = list(range(n))
Choice_of_workers = list(it.combinations(workers, k))
size_total = np.shape(Choice_of_workers)
total_no_choices = size_total[0]
best_mat_A = {}
best_mat_B = {}
mu = 0
sigma = 1
min_eigenvalue = np.zeros(total_no_choices * samples_in_omega)
max_eigenvalue = np.zeros(total_no_choices * samples_in_omega)
condition_number = np.zeros(no_trials, dtype=float)
for trial in range(0, no_trials):
best_mat_A[trial] = np.random.normal(mu, sigma, [kA, s])
best_mat_B[trial] = np.random.normal(mu, sigma, [kB, s])
matrices = {}
matrices[0] = best_mat_A[trial]
matrices[1] = best_mat_B[trial]
best_mat_comb = np.zeros((kA * kB, s))
for i in range(s):
cum_prod = matrices[0][:, i]
cum_prod = np.einsum('i,j->ij', cum_prod, matrices[1][:,
i]).ravel()
best_mat_comb[:, i] = cum_prod
ind = 0
exponent_vector = list(range(0, kB))
for i in range(1, kA):
m = i * z
exponent_vector = np.concatenate(
(exponent_vector, list(range(m, m + kB))), axis=0)
w = np.zeros(2 * samples_in_omega, dtype=float)
for i in range(0, samples_in_omega):
w[i] = -np.pi + i * 2 * np.pi / samples_in_omega
zz = samples_in_omega
for z in range(0, zz):
imag = 1j
omega = np.zeros((k, s), dtype=complex)
for i in range(0, s):
omega[:, i] = np.power(np.exp(-imag * w[z])**i, list(range(k)))
Generator_mat = np.concatenate(
(identity_part, np.multiply(best_mat_comb, omega)), axis=1)
for i in range(0, total_no_choices):
Coding_matrix = []
kk = list(Choice_of_workers[i])
Coding_matrix = Generator_mat[:, kk]
Coding_matrixT = np.transpose(Coding_matrix)
D = np.matmul(np.conjugate(Coding_matrixT), Coding_matrix)
eigenvalues = eigvals(D)
eigenvalues = np.real(eigenvalues)
min_eigenvalue[ind] = np.min(eigenvalues)
max_eigenvalue[ind] = np.max(eigenvalues)
ind = ind + 1
condition_number[trial] = np.sqrt(
np.max(max_eigenvalue) / np.min(min_eigenvalue))
best_cond_min = np.min(condition_number)
position = np.argmin(condition_number)
R_A = best_mat_A[position]
R_B = best_mat_B[position]
return R_A, R_B, best_cond_min
def balfreq(SS, DictBalFreq):
'''
Method for frequency limited balancing.
The Observability ad controllability Gramians over the frequencies kv
are solved in factorised form. Balancd modes are then obtained with a
square-root method.
Details:
Observability and controllability Gramians are solved in factorised form
through explicit integration. The number of integration points determines
both the accuracy and the maximum size of the balanced model.
Stability over all (Nb) balanced states is achieved if:
a. one of the Gramian is integrated through the full Nyquist range
b. the integration points are enough.
Input:
- DictBalFreq: dictionary specifying integration method with keys:
- 'frequency': defines limit frequencies for balancing. The balanced
model will be accurate in the range [0,F], where F is the value of
this key. Note that F units must be consistent with the units specified
in the self.ScalingFacts dictionary.
- 'method_low': ['gauss','trapz'] specifies whether to use gauss
quadrature or trapezoidal rule in the low-frequency range [0,F]
- 'options_low': options to use for integration in the low-frequencies.
These depend on the integration scheme (See below).
- 'method_high': method to use for integration in the range [F,F_N],
where F_N is the Nyquist frequency. See 'method_low'.
- 'options_high': options to use for integration in the high-frequencies.
- 'check_stability': if True, the balanced model is truncated to
eliminate unstable modes - if any is found. Note that very accurate
balanced model can still be obtained, even if high order modes are
unstable. Note that this option is overridden if ""
- 'get_frequency_response': if True, the function also returns the
frequency response evaluated at the low-frequency range integration
points. If True, this option also allows to automatically tune the
balanced model.
Future options:
- Ncpu: for parallel run
The following integration schemes are available:
- 'trapz': performs integration over equally spaced points using
trapezoidal rule. It accepts options dictionaries with keys:
- 'points': number of integration points to use (including
domain boundary)
- 'gauss' performs gauss-lobotto quadrature. The domain can be
partitioned in Npart sub-domain in which the gauss-lobotto quadrature
of order Ord can be applied. A total number of Npart*Ord points is
required. It accepts options dictionaries of the form:
- 'partitions': number of partitions
- 'order': quadrature order.
Example:
The following dictionary
DictBalFreq={ 'frequency': 1.2,
'method_low': 'trapz',
'options_low': {'points': 12},
'method_high': 'gauss',
'options_high': {'partitions': 2, 'order': 8},
'check_stability': True }
balances the state-space model in the frequency range [0, 1.2]
using
(a) 12 equally-spaced points integration of the Gramians in
the low-frequency range [0,1.2] and
(b) a 2 Gauss-Lobotto 8-th order quadratures of the controllability
Gramian in the high-frequency range.
A total number of 28 integration points will be required, which will
result into a balanced model with number of states
min{ 2*28* number_inputs, 2*28* number_outputs }
The model is finally truncated so as to retain only the first Ns stable
modes.
'''
### check input dictionary
if 'frequency' not in DictBalFreq:
raise NameError('Solution dictionary must include the "frequency" key')
if 'method_low' not in DictBalFreq:
warnings.warn('Setting default options for low-frequency integration')
DictBalFreq['method_low'] = 'trapz'
DictBalFreq['options_low'] = {'points': 12}
if 'method_high' not in DictBalFreq:
warnings.warn('Setting default options for high-frequency integration')
DictBalFreq['method_high'] = 'gauss'
DictBalFreq['options_high'] = {'partitions': 2, 'order': 8}
if 'check_stability' not in DictBalFreq:
DictBalFreq['check_stability'] = True
if 'output_modes' not in DictBalFreq:
DictBalFreq['output_modes'] = True
if 'get_frequency_response' not in DictBalFreq:
DictBalFreq['get_frequency_response'] = False
### get integration points and weights
# Nyquist frequency
kn = np.pi / SS.dt
Opt = DictBalFreq['options_low']
if DictBalFreq['method_low'] == 'trapz':
kv_low, wv_low = get_trapz_weights(0., DictBalFreq['frequency'],
Opt['points'], False)
elif DictBalFreq['method_low'] == 'gauss':
kv_low, wv_low = get_gauss_weights(0., DictBalFreq['frequency'],
Opt['partitions'], Opt['order'])
else:
raise NameError('Invalid value %s for key "method_low"' %
DictBalFreq['method_low'])
Opt = DictBalFreq['options_high']
if DictBalFreq['method_high'] == 'trapz':
if Opt['points'] == 0:
warnings.warn('You have chosen no points in high frequency range!')
kv_high, wv_high = [], []
else:
kv_high, wv_high = get_trapz_weights(DictBalFreq['frequency'], kn,
Opt['points'], True)
elif DictBalFreq['method_high'] == 'gauss':
if Opt['order'] * Opt['partitions'] == 0:
warnings.warn('You have chosen no points in high frequency range!')
kv_high, wv_high = [], []
else:
kv_high, wv_high = get_gauss_weights(DictBalFreq['frequency'], kn,
Opt['partitions'],
Opt['order'])
else:
raise NameError('Invalid value %s for key "method_high"' %
DictBalFreq['method_high'])
### -------------------------------------------------- loop frequencies
### merge vectors
Nk_low = len(kv_low)
kvdt = np.concatenate((kv_low, kv_high)) * SS.dt
wv = np.concatenate((wv_low, wv_high)) * SS.dt
zv = np.cos(kvdt) + 1.j * np.sin(kvdt)
Eye = libsp.eye_as(SS.A)
Zc = np.zeros((SS.states, 2 * SS.inputs * len(kvdt)), )
Zo = np.zeros((SS.states, 2 * SS.outputs * Nk_low), )
if DictBalFreq['get_frequency_response']:
Yfreq = np.empty((
SS.outputs,
SS.inputs,
Nk_low,
), dtype=np.complex_)
kv = kv_low
for kk in range(len(kvdt)):
zval = zv[kk]
Intfact = wv[kk] # integration factor
Qctrl = Intfact * libsp.solve(zval * Eye - SS.A, SS.B)
kkvec = range(2 * kk * SS.inputs, 2 * (kk + 1) * SS.inputs)
Zc[:, kkvec[:SS.inputs]] = Qctrl.real
Zc[:, kkvec[SS.inputs:]] = Qctrl.imag
### ----- frequency response
if DictBalFreq['get_frequency_response'] and kk < Nk_low:
Yfreq[:,:,kk]= (1./Intfact)*\
libsp.dot(SS.C,Qctrl,type_out=np.ndarray)+SS.D
### ----- observability
if kk >= Nk_low:
continue
Qobs = Intfact * libsp.solve(np.conj(zval) * Eye - SS.A.T, SS.C.T)
kkvec = range(2 * kk * SS.outputs, 2 * (kk + 1) * SS.outputs)
Zo[:, kkvec[:SS.outputs]] = Intfact * Qobs.real
Zo[:, kkvec[SS.outputs:]] = Intfact * Qobs.imag
# delete full matrices
Kernel = None
Qctrl = None
Qobs = None
# LRSQM (optimised)
U, hsv, Vh = scalg.svd(np.dot(Zo.T, Zc), full_matrices=False)
sinv = hsv**(-0.5)
T = np.dot(Zc, Vh.T * sinv)
Ti = np.dot((U * sinv).T, Zo.T)
# Zc,Zo=None,None
### build frequency balanced model
Ab = libsp.dot(Ti, libsp.dot(SS.A, T))
Bb = libsp.dot(Ti, SS.B)
Cb = libsp.dot(SS.C, T)
SSb = libss.ss(Ab, Bb, Cb, SS.D, dt=SS.dt)
### Eliminate unstable modes - if any:
if DictBalFreq['check_stability']:
for nn in range(1, len(hsv) + 1):
eigs_trunc = scalg.eigvals(SSb.A[:nn, :nn])
eigs_trunc_max = np.max(np.abs(eigs_trunc))
if eigs_trunc_max > 1. - 1e-16:
SSb.truncate(nn - 1)
hsv = hsv[:nn - 1]
T = T[:, :nn - 1]
Ti = Ti[:nn - 1, :]
break
outs = (SSb, hsv)
if DictBalFreq['output_modes']:
outs += (T, Ti, Zc, Zo, U, Vh)
return outs
def system_norm(G, p=np.inf, hinf_tol=1e-6, eig_tol=1e-8):
"""
Computes the system p-norm. Currently, no balancing is done on the
system, however in the future, a scaling of some sort will be introduced.
Currently, only H₂ and H∞-norm are understood.
For H₂-norm, the standard grammian definition via controllability grammian,
that can be found elsewhere is used.
Parameters
----------
G : {State,Transfer}
System for which the norm is computed
p : {int,np.inf}
The norm type; `np.inf` for H∞- and `2` for H2-norm
hinf_tol: float
When the progress is below this tolerance the result is accepted
as converged.
eig_tol: float
The algorithm relies on checking the eigenvalues of the Hamiltonian
being on the imaginary axis or not. This value is the threshold
such that the absolute real value of the eigenvalues smaller than
this value will be accepted as pure imaginary eigenvalues.
Returns
-------
n : float
Resulting p-norm
Notes
-----
The H∞ norm is computed via the so-called BBBS algorithm ([1]_, [2]_).
.. [1] N.A. Bruinsma, M. Steinbuch: Fast Computation of H∞-norm of
transfer function. System and Control Letters, 14, 1990.
:doi:`10.1016/0167-6911(90)90049-Z`
.. [2] S. Boyd and V. Balakrishnan. A regularity result for the singular
values of a transfer matrix and a quadratically convergent
algorithm for computing its L∞-norm. System and Control Letters,
1990. :doi:`10.1016/0167-6911(90)90037-U`
"""
# Tried the corrections given in arXiv:1707.02497, couldn't get the gains
# mentioned in the paper.
_check_for_state_or_transfer(G)
if p not in (2, np.inf):
raise ValueError('The p in p-norm is not 2 or infinity. If you'
' tried the string \'inf\', use "np.inf" instead')
T = transfer_to_state(G) if isinstance(G, Transfer) else G
a, b, c, d = T.matrices
# 2-norm
if p == 2:
# Handle trivial infinities
if not np.allclose(T.d, np.zeros_like(T.d)) or (not T._isstable):
return np.Inf
if T.SamplingSet == 'R':
x = lyapunov_eq_solver(a.T, b @ b.T)
return np.sqrt(np.trace(c @ x @ c.T))
else:
x = lyapunov_eq_solver(a.T, b @ b.T, form='d')
return np.sqrt(np.trace(c @ x @ c.T + d @ d.T))
# ∞-norm
elif np.isinf(p):
if not T._isstable:
return np.Inf
# Initial gamma0 guess
# Get the max of the largest svd of either
# - feedthrough matrix
# - G(iw) response at the pole with smallest damping
# - G(iw) at w = 0
# Formula (4.3) given in Bruinsma, Steinbuch Sys.Cont.Let. (1990)
if any(T.poles.imag):
J = [np.abs(x.imag / x.real / np.abs(x)) for x in T.poles]
ind = np.argmax(J)
low_damp_fr = np.abs(T.poles[ind])
else:
low_damp_fr = np.min(np.abs(T.poles))
f, w = frequency_response(T,
w=[0, low_damp_fr],
w_unit='rad/s',
output_unit='rad/s')
if T._isSISO:
lb = np.max(np.abs(f))
else:
# Only evaluated at two frequencies, 0 and wb
lb = np.max(norm(f, ord=2, axis=(0, 1)))
# Finally
gamma_lb = np.max([lb, norm(d, ord=2)])
# Start a for loop with a definite end! Convergence is quartic!!
for x in range(51):
# (Step b1)
test_gamma = gamma_lb * (1 + 2 * np.sqrt(np.spacing(1.)))
# (Step b2)
R = d.T @ d - test_gamma**2 * np.eye(d.shape[1])
S = d @ d.T - test_gamma**2 * np.eye(d.shape[0])
# TODO : Implement the result of Benner for the Hamiltonian later
mat = block(
[[a - b @ solve(R, d.T) @ c, -test_gamma * b @ solve(R, b.T)],
[
test_gamma * c.T @ solve(S, c),
-(a - b @ solve(R, d.T) @ c).T
]])
eigs_of_H = eigvals(mat)
# (Step b3)
im_eigs = eigs_of_H[np.abs(eigs_of_H.real) <= eig_tol]
# If none left break
if im_eigs.size == 0:
gamma_ub = test_gamma
break
else:
# Take the ones with positive imag part
w_i = np.sort(np.unique(np.abs(im_eigs.imag)))
# Evaluate the cubic interpolant
m_i = (w_i[1:] + w_i[:-1]) / 2
f, w = frequency_response(T,
w=m_i,
w_unit='rad/s',
output_unit='rad/s')
if T._isSISO:
gamma_lb = np.max(np.abs(f))
else:
gamma_lb = np.max(norm(f, ord=2, axis=(0, 1)))
return (gamma_lb + gamma_ub) / 2
for i in range(0, 7):
cmat[i][i] = 1
cmat[0][1] = cmat[1][0] = spst.pearsonr(data.det, data.lam)[0]
cmat[0][2] = cmat[2][0] = spst.pearsonr(data.det, data.lamdet)[0]
cmat[0][3] = cmat[3][0] = spst.pearsonr(data.det, data.lavg)[0]
cmat[0][4] = cmat[4][0] = spst.pearsonr(data.det, data.lent)[0]
cmat[0][5] = cmat[5][0] = spst.pearsonr(data.det, data.vavg)[0]
cmat[0][6] = cmat[6][0] = spst.pearsonr(data.det, data.vent)[0]
cmat[1][2] = cmat[2][1] = spst.pearsonr(data.lam, data.lamdet)[0]
cmat[1][3] = cmat[3][1] = spst.pearsonr(data.lam, data.lavg)[0]
cmat[1][4] = cmat[4][1] = spst.pearsonr(data.lam, data.lent)[0]
cmat[1][5] = cmat[5][1] = spst.pearsonr(data.lam, data.vavg)[0]
cmat[1][6] = cmat[6][1] = spst.pearsonr(data.lam, data.vent)[0]
cmat[2][3] = cmat[3][2] = spst.pearsonr(data.lamdet, data.lavg)[0]
cmat[2][4] = cmat[4][2] = spst.pearsonr(data.lamdet, data.lent)[0]
cmat[2][5] = cmat[5][2] = spst.pearsonr(data.lamdet, data.vavg)[0]
cmat[2][6] = cmat[6][2] = spst.pearsonr(data.lamdet, data.vent)[0]
cmat[3][4] = cmat[4][3] = spst.pearsonr(data.lavg, data.lent)[0]
cmat[3][5] = cmat[5][3] = spst.pearsonr(data.lavg, data.vavg)[0]
cmat[3][6] = cmat[6][3] = spst.pearsonr(data.lavg, data.vent)[0]
cmat[4][5] = cmat[5][4] = spst.pearsonr(data.lent, data.vavg)[0]
cmat[4][6] = cmat[6][4] = spst.pearsonr(data.lent, data.vent)[0]
cmat[5][6] = cmat[6][5] = spst.pearsonr(data.vavg, data.vent)[0]
print cmat
b = spl.eigvals(abs(cmat))
print b
bvar = np.var(b)
meff = 1 + ((6) * (1 - (bvar / 7)))
print meff
def _ideal_tfinal_and_dt(sys, is_step=True):
"""helper function to compute ideal simulation duration tfinal and dt, the
time increment. Usually called by _default_time_vector, whose job it is to
choose a realistic time vector. Considers both poles and zeros.
For discrete-time models, dt is inherent and only tfinal is computed.
Parameters
----------
sys : StateSpace or TransferFunction
The system whose time response is to be computed
is_step : bool
Scales the dc value by the magnitude of the nonzero mode since
integrating the impulse response gives
:math:`\int e^{-\lambda t} = -e^{-\lambda t}/ \lambda`
Default is True.
Returns
-------
tfinal : float
The final time instance for which the simulation will be performed.
dt : float
The estimated sampling period for the simulation.
Notes
-----
Just by evaluating the fastest mode for dt and slowest for tfinal often
leads to unnecessary, bloated sampling (e.g., Transfer(1,[1,1001,1000]))
since dt will be very small and tfinal will be too large though the fast
mode hardly ever contributes. Similarly, change the numerator to [1, 2, 0]
and the simulation would be unnecessarily long and the plot is virtually
an L shape since the decay is so fast.
Instead, a modal decomposition in time domain hence a truncated ZIR and ZSR
can be used such that only the modes that have significant effect on the
time response are taken. But the sensitivity of the eigenvalues complicate
the matter since dlambda = <w, dA*v> with <w,v> = 1. Hence we can only work
with simple poles with this formulation. See Golub, Van Loan Section 7.2.2
for simple eigenvalue sensitivity about the nonunity of <w,v>. The size of
the response is dependent on the size of the eigenshapes rather than the
eigenvalues themselves.
By Ilhan Polat, with modifications by Sawyer Fuller to integrate into
python-control 2020.08.17
"""
sqrt_eps = np.sqrt(np.spacing(1.))
default_tfinal = 5 # Default simulation horizon
default_dt = 0.1
total_cycles = 5 # number of cycles for oscillating modes
pts_per_cycle = 25 # Number of points divide a period of oscillation
log_decay_percent = np.log(100) # Factor of reduction for real pole decays
if sys.is_static_gain():
tfinal = default_tfinal
dt = sys.dt if isdtime(sys, strict=True) else default_dt
elif isdtime(sys, strict=True):
dt = sys.dt
A = _convertToStateSpace(sys).A
tfinal = default_tfinal
p = eigvals(A)
# Array Masks
# unstable
m_u = (np.abs(p) >= 1 + sqrt_eps)
p_u, p = p[m_u], p[~m_u]
if p_u.size > 0:
m_u = (p_u.real < 0) & (np.abs(p_u.imag) < sqrt_eps)
t_emp = np.max(log_decay_percent / np.abs(np.log(p_u[~m_u]) / dt))
tfinal = max(tfinal, t_emp)
# zero - negligible effect on tfinal
m_z = np.abs(p) < sqrt_eps
p = p[~m_z]
# Negative reals- treated as oscillary mode
m_nr = (p.real < 0) & (np.abs(p.imag) < sqrt_eps)
p_nr, p = p[m_nr], p[~m_nr]
if p_nr.size > 0:
t_emp = np.max(log_decay_percent / np.abs(
(np.log(p_nr) / dt).real))
tfinal = max(tfinal, t_emp)
# discrete integrators
m_int = (p.real - 1 < sqrt_eps) & (np.abs(p.imag) < sqrt_eps)
p_int, p = p[m_int], p[~m_int]
# pure oscillatory modes
m_w = (np.abs(np.abs(p) - 1) < sqrt_eps)
p_w, p = p[m_w], p[~m_w]
if p_w.size > 0:
t_emp = total_cycles * 2 * np.pi / np.abs(np.log(p_w) / dt).min()
tfinal = max(tfinal, t_emp)
if p.size > 0:
t_emp = log_decay_percent / np.abs((np.log(p) / dt).real).min()
tfinal = max(tfinal, t_emp)
if p_int.size > 0:
tfinal = tfinal * 5
else: # cont time
sys_ss = _convertToStateSpace(sys)
# Improve conditioning via balancing and zeroing tiny entries
# See <w,v> for [[1,2,0], [9,1,0.01], [1,2,10*np.pi]] before/after balance
b, (sca, perm) = matrix_balance(sys_ss.A, separate=True)
p, l, r = eig(b, left=True, right=True)
# Reciprocal of inner product <w,v> for each eigval, (bound the ~infs by 1e12)
# G = Transfer([1], [1,0,1]) gives zero sensitivity (bound by 1e-12)
eig_sens = np.reciprocal(maximum(1e-12, einsum('ij,ij->j', l, r).real))
eig_sens = minimum(1e12, eig_sens)
# Tolerances
p[np.abs(p) < np.spacing(eig_sens * norm(b, 1))] = 0.
# Incorporate balancing to outer factors
l[perm, :] *= np.reciprocal(sca)[:, None]
r[perm, :] *= sca[:, None]
w, v = sys_ss.C.dot(r), l.T.conj().dot(sys_ss.B)
origin = False
# Computing the "size" of the response of each simple mode
wn = np.abs(p)
if np.any(wn == 0.):
origin = True
dc = np.zeros_like(p, dtype=float)
# well-conditioned nonzero poles, np.abs just in case
ok = np.abs(eig_sens) <= 1 / sqrt_eps
# the averaged t->inf response of each simple eigval on each i/o channel
# See, A = [[-1, k], [0, -2]], response sizes are k-dependent (that is
# R/L eigenvector dependent)
dc[ok] = norm(v[ok, :], axis=1) * norm(w[:, ok], axis=0) * eig_sens[ok]
dc[wn != 0.] /= wn[wn != 0] if is_step else 1.
dc[wn == 0.] = 0.
# double the oscillating mode magnitude for the conjugate
dc[p.imag != 0.] *= 2
# Now get rid of noncontributing integrators and simple modes if any
relevance = (dc > 0.1 * dc.max()) | ~ok
psub = p[relevance]
wnsub = wn[relevance]
tfinal, dt = [], []
ints = wnsub == 0.
iw = (psub.imag != 0.) & (np.abs(psub.real) <= sqrt_eps)
# Pure imaginary?
if np.any(iw):
tfinal += (total_cycles * 2 * np.pi / wnsub[iw]).tolist()
dt += (2 * np.pi / pts_per_cycle / wnsub[iw]).tolist()
# The rest ~ts = log(%ss value) / exp(Re(eigval)t)
texp_mode = log_decay_percent / np.abs(psub[~iw & ~ints].real)
tfinal += texp_mode.tolist()
dt += minimum(
texp_mode / 50,
(2 * np.pi / pts_per_cycle / wnsub[~iw & ~ints])).tolist()
# All integrators?
if len(tfinal) == 0:
return default_tfinal * 5, default_dt * 5
tfinal = np.max(tfinal) * (5 if origin else 1)
dt = np.min(dt)
return tfinal, dt
def ispos(mat):
evals = eigvals(mat)
if np.all(evals >= 0.0):
return True
return False
def analyseMatrix(M):
print('Negative eigenvalues:',
[(v, i) for (v, i) in enumerate(linalg.eigvals(M)) if v < 0])
print('Symmetric: ', np.allclose(M, M.T))
# Trigonometric functions - sinm, cosm, tanm linalg.sinm(A_sq) linalg.sinm(A_non_sq) # Hyperbolic trigonometric functions - sinhm, coshm, tanhm linalg.sinhm(A_sq) linalg.sinhm(A_non_sq) # Arbitrary function from scipy import special, random, linalg np.random.seed(1234) A = random.rand(3, 3) B = linalg.funm(A, lambda x: special.jv(0, x)) A B linalg.eigvals(A) special.jv(0, linalg.eigvals(A)) linalg.eigvals(B) # ----------------------------------------------------------------------------- # SPARSE EIGENVALUE PROBLEMS WITH ARPACK # Can be used to find only smallest/largest/real/complex part eigenvalues from scipy.linalg import eig, eigh from scipy.sparse.linalg import eigs, eigsh np.set_printoptions(suppress = True) np.random.seed(0)
### EIGENVALUE PROBLEMS ### =================== # (1): eig # --- # Solve an ordinary or generalized eigenvalue problem of a square matrix. print(linalg.eig(a)) # (2): eigvals # --- # Compute eigenvalues from an ordinary or generalized eigenvalue problem. print(linalg.eigvals(a)) ################################################################################################### ### =============== ### DESCOMPOSITIONS ### =============== # (1.a): lu # --- # Compute pivoted LU decomposition of a matrix. P, L, U = linalg.lu(a) print(P)
# Make the scaling matrix for RHS of equation
RHS = eye(10 * vLen, 10 * vLen)
RHS[:3 * vLen, :3 * vLen] = Re * eye(3 * vLen, 3 * vLen)
# Zero all elements corresponding to p equation
RHS[3 * vLen:4 * vLen, :] = zeros((vLen, 10 * vLen))
# Apply boundary conditions to RHS
for i in range(3 * (2 * N + 1)):
RHS[M * (i + 1) - 1, M * (i + 1) - 1] = 0
RHS[M * (i + 1) - 2, M * (i + 1) - 2] = 0
del i
# Use library function to solve for eigenvalues/vectors
print 'in linalg.eig time=', (time.time() - startTime)
eigenvals = linalg.eigvals(equations_matrix, RHS, overwrite_a=True)
# Save output
eigarray = vstack((real(eigenvals), imag(eigenvals))).T
#remove nans and infs from eigenvalues
eigarray = eigarray[~isnan(eigarray).any(1), :]
eigarray = eigarray[~isinf(eigarray).any(1), :]
savetxt(
'ev-k{k}{file}-redn{Nselect}.dat'.format(k=k,
file=filename[:-7],
Nselect=Nselect), eigarray)
#stop the clock
print 'done in', (time.time() - startTime)
def test_simple_complex(self):
a = [[1, 2, 3], [1, 2, 3], [2, 5, 6 + 1j]]
w = eigvals(a)
exact_w = [(9 + 1j + sqrt(92 + 6j)) / 2, 0,
(9 + 1j - sqrt(92 + 6j)) / 2]
assert_array_almost_equal(w, exact_w)
def h_infinity_norm(ss, **kwargs):
r"""
Returns H-infinity norm of a linear system using iterative methods.
The H-infinity norm of a MIMO system is traditionally calculated finding the largest SVD of the
transfer function evaluated across the entire frequency spectrum. That can prove costly for a
large number of evaluations, hence the iterative methods of [1] are employed.
In the case of a SISO system the H-infinity norm corresponds to the maximum frequency gain.
A scalar value is returned if the system is stable. If the system is unstable it returns ``np.Inf``.
References:
[1] Bruinsma, N. A., & Steinbuch, M. (1990). A fast algorithm to compute the H∞-norm of a transfer function
matrix. Systems and Control Letters, 14(4), 287–293. https://doi.org/10.1016/0167-6911(90)90049-Z
Args:
ss (sharpy.linear.src.libss.ss): Multi input multi output system.
**kwargs: Key-word arguments.
Keyword Args:
tol (float (optional)): Tolerance. Defaults to ``1e-7``.
tol_imag_eigs (float (optional)): Tolerance to find purely imaginary eigenvalues. Defaults to ``1e-7``.
iter_max (int (optional)): Maximum number of iterations.
print_info (bool (optional)): Print status and information. Defaults to ``False``.
Returns:
float: H-infinity norm of the system.
"""
tol = kwargs.get('tol', 1e-7)
iter_max = kwargs.get('iter_max', 10)
print_info = kwargs.get('print_info', False)
# tolerance to find purely imaginary eigenvalues i.e those with Re(eig) < tol_imag_eigs
tol_imag_eigs = kwargs.get('tol_imag_eigs', 1e-7)
if ss.dt is not None:
ss = libss.disc2cont(ss)
# 1) Compute eigenvalues of original system
eigs = sclalg.eigvals(ss.A)
if any(eigs.real > tol_imag_eigs):
if print_info:
try:
cout.cout_wrap('System is unstable - H-inf = np.inf')
except ValueError:
print('System is unstable - H-inf = np.inf')
return np.inf
# 2) Find eigenvalue that maximises equation. If all real pick largest eig
if np.max(np.abs(eigs.imag) < tol_imag_eigs):
eig_m = np.max(eigs.real)
else:
eig_m, _ = max_eigs(eigs)
# 3) Choose best option for gamma_lb
max_steady_state = np.max(
sclalg.svd(ss.transfer_function_evaluation(0), compute_uv=False))
max_eig_m = np.max(
sclalg.svd(ss.transfer_function_evaluation(1j * np.abs(eig_m)),
compute_uv=False))
max_d = np.max(sclalg.svd(ss.D, compute_uv=False))
gamma_lb = max(max_steady_state, max_eig_m, max_d)
iter_num = 0
if print_info:
try:
cout.cout_wrap(
'Calculating H-inf norm\n{0:>4s} ::::: {1:^8s}'.format(
'Iter', 'Hinf'))
except ValueError:
print('Calculating H_inf norm\n{0:>4s} ::::: {1:^8s}'.format(
'Iter', 'Hinf'))
while iter_num < iter_max:
if print_info:
try:
cout.cout_wrap('{0:>4g} ::::: {1:>8.2e}'.format(
iter_num, gamma_lb))
except ValueError:
print('{0:>4g} ::::: {1:>8.2e}'.format(iter_num, gamma_lb))
gamma = (1 + 2 * tol) * gamma_lb
# 4) compute hamiltonian and eigenvalues
ham = hamiltonian(gamma, ss)
eigs = sclalg.eigvals(ham)
# If eigenvalues all eigenvalues are purely imaginary
if any(np.abs(eigs.real) < tol_imag_eigs):
# Select imaginary eigenvalues and those with positive values
condition_imag = (np.abs(eigs.real) <
tol_imag_eigs) * eigs.imag > 0
imag_eigs = eigs[condition_imag].imag
# Sort them in decreasing order
order = np.argsort(imag_eigs)[::-1]
imag_eigs = imag_eigs[order]
if len(imag_eigs) == 1:
m = imag_eigs[0]
svdmax = np.max(
sclalg.svd(ss.transfer_function_evaluation(1j * m),
compute_uv=False))
gamma_lb = svdmax
else:
m_list = [
0.5 * (imag_eigs[i] + imag_eigs[i + 1])
for i in range(len(imag_eigs) - 1)
]
svdmax = [
np.max(
sclalg.svd(ss.transfer_function_evaluation(1j * m),
compute_uv=False)) for m in m_list
]
gamma_lb = max(svdmax)
else:
gamma_ub = gamma
break
iter_num += 1
if iter_num == iter_max:
raise np.linalg.LinAlgError(
'Unconverged H-inf solution after %g iterations' % iter_num)
hinf = 0.5 * (gamma_lb + gamma_ub)
return hinf
def SRLS(anchors, w, r2, rescale=False, z=None, print_out=False):
'''Squared range least squares (SRLS)
Algorithm written by A.Beck, P.Stoica in "Approximate and Exact solutions of Source Localization Problems".
:param anchors: anchor points (Nxd)
:param w: weights for the measurements (Nx1)
:param r2: squared distances from anchors to point x. (Nx1)
:param rescale: Optional parameter. When set to True, the algorithm will
also identify if there is a global scaling of the measurements. Such a
situation arise for example when the measurement units of the distance is
unknown and different from that of the anchors locations (e.g. anchors are
in meters, distance in centimeters).
:param z: Optional parameter. Use to fix the z-coordinate of localized point.
:param print_out: Optional parameter, prints extra information.
:return: estimated position of point x.
'''
def y_hat(_lambda):
lhs = ATA + _lambda * D
assert A.shape[0] == b.shape[0]
assert A.shape[1] == f.shape[0], 'A {}, f {}'.format(A.shape, f.shape)
rhs = (np.dot(A.T, b) - _lambda * f).reshape((-1, ))
assert lhs.shape[0] == rhs.shape[0], 'lhs {}, rhs {}'.format(
lhs.shape, rhs.shape)
try:
return np.linalg.solve(lhs, rhs)
except:
return np.zeros((lhs.shape[1], ))
def phi(_lambda):
yhat = y_hat(_lambda).reshape((-1, 1))
sol = np.dot(yhat.T, np.dot(D, yhat)) + 2 * np.dot(f.T, yhat)
return sol.flatten()
def phi_prime(_lambda):
# TODO: test this.
B = np.linalg.inv(ATA + _lambda * D)
C = A.T.dot(b) - _lambda * f
y_prime = -B.dot(D.dot(B.dot(C)) - f)
y = y_hat(_lambda)
return 2 * y.T.dot(D).dot(y_prime) + 2 * f.T.dot(y_prime)
from scipy import optimize
from scipy.linalg import sqrtm
n, d = anchors.shape
assert r2.shape[1] == 1 and r2.shape[0] == n, 'r2 has to be of shape Nx1'
assert w.shape[1] == 1 and w.shape[0] == n, 'w has to be of shape Nx1'
if z is not None:
assert d == 3, 'Dimension of problem has to be 3 for fixing z.'
if rescale and z is not None:
raise NotImplementedError('Cannot run rescale for fixed z.')
if rescale and n < d + 2:
raise ValueError(
'A minimum of d + 2 ranges are necessary for rescaled ranging.')
elif n < d + 1 and z is None:
raise ValueError(
'A minimum of d + 1 ranges are necessary for ranging.')
elif n < d:
raise ValueError('A minimum of d ranges are necessary for ranging.')
Sigma = np.diagflat(np.power(w, 0.5))
if rescale:
A = np.c_[-2 * anchors, np.ones((n, 1)), -r2]
else:
if z is None:
A = np.c_[-2 * anchors, np.ones((n, 1))]
else:
A = np.c_[-2 * anchors[:, :2], np.ones((n, 1))]
A = Sigma.dot(A)
if rescale:
b = -np.power(np.linalg.norm(anchors, axis=1), 2).reshape(r2.shape)
else:
b = r2 - np.power(np.linalg.norm(anchors, axis=1), 2).reshape(r2.shape)
if z is not None:
b = b + 2 * anchors[:, 2].reshape((-1, 1)) * z - z**2
b = Sigma.dot(b)
ATA = np.dot(A.T, A)
if rescale:
D = np.zeros((d + 2, d + 2))
D[:d, :d] = np.eye(d)
else:
if z is None:
D = np.zeros((d + 1, d + 1))
else:
D = np.zeros((d, d))
D[:-1, :-1] = np.eye(D.shape[0] - 1)
if rescale:
f = np.c_[np.zeros((1, d)), -0.5, 0.].T
elif z is None:
f = np.c_[np.zeros((1, d)), -0.5].T
else:
f = np.c_[np.zeros((1, 2)), -0.5].T
eig = np.sort(np.real(eigvalsh(a=D, b=ATA)))
if (print_out):
print('ATA:', ATA)
print('rank:', np.linalg.matrix_rank(A))
print('eigvals:', eigvals(ATA))
print('condition number:', np.linalg.cond(ATA))
print('generalized eigenvalues:', eig)
#eps = 0.01
if eig[-1] > 1e-10:
lower_bound = -1.0 / eig[-1]
else:
print('Warning: biggest eigenvalue is zero!')
lower_bound = -1e-5
inf = 1e5
xtol = 1e-12
lambda_opt = 0
# We will look for the zero of phi between lower_bound and inf.
# Therefore, the two have to be of different signs.
if (phi(lower_bound) > 0) and (phi(inf) < 0):
# brentq is considered the best rootfinding routine.
try:
lambda_opt = optimize.brentq(phi, lower_bound, inf, xtol=xtol)
except:
print(
'SRLS error: brentq did not converge even though we found an estimate for lower and upper bonud. Setting lambda to 0.'
)
else:
try:
lambda_opt = optimize.newton(phi,
lower_bound,
fprime=phi_prime,
maxiter=1000,
tol=xtol,
verbose=True)
assert phi(
lambda_opt
) < xtol, 'did not find solution of phi(lambda)=0:={}'.format(
phi(lambda_opt))
except:
print('SRLS error: newton did not converge. Setting lambda to 0.')
if (print_out):
print('phi(lower_bound)', phi(lower_bound))
print('phi(inf)', phi(inf))
print('phi(lambda_opt)', phi(lambda_opt))
pos_definite = ATA + lambda_opt * D
eig = np.sort(np.real(eigvals(pos_definite)))
print('should be strictly bigger than 0:', eig)
# Compute best estimate
yhat = y_hat(lambda_opt)
if print_out and rescale:
print('Scaling factor :', yhat[-1])
if rescale:
return yhat[:d], yhat[-1]
elif z is None:
return yhat[:d]
else:
return np.r_[yhat[0], yhat[1], z]
def _compute_tfinal_and_dt(sys, is_step=True):
"""
Helper function to estimate a final time and a sampling period for
time domain simulations. It is essentially geared towards impulse response
but is also used for step responses.
For discrete-time models, obviously dt is inherent and only tfinal is
computed.
Parameters
----------
sys : {State, Transfer}
The system to be investigated
is_step : bool
Scales the dc value by the magnitude of the nonzero mode since
integrating the impulse response gives ∫exp(-λt) = -exp(-λt)/λ.
Default is True.
Returns
-------
tfinal : float
The final time instance for which the simulation will be performed.
dt : float
The estimated sampling period for the simulation.
Notes
-----
Just by evaluating the fastest mode for dt and slowest for tfinal often
leads to unnecessary, bloated sampling (e.g., Transfer(1,[1,1001,1000]))
since dt will be very small and tfinal will be too large though the fast
mode hardly ever contributes. Similarly, change the numerator to [1, 2, 0]
and the simulation would be unnecessarily long and the plot is virtually
an L shape since the decay is so fast.
Instead, a modal decomposition in time domain hence a truncated ZIR and ZSR
can be used such that only the modes that have significant effect on the
time response are taken. But the sensitivity of the eigenvalues complicate
the matter since dλ = <w, dA*v> with <w,v> = 1. Hence we can only work
with simple poles with this formulation. See Golub, Van Loan Section 7.2.2
for simple eigenvalue sensitivity about the nonunity of <w,v>. The size of
the response is dependent on the size of the eigenshapes rather than the
eigenvalues themselves.
"""
sqrt_eps = np.sqrt(np.spacing(1.))
min_points = 100 # min number of points
min_points_z = 20 # min number of points
max_points = 10000 # max number of points
max_points_z = 75000 # max number of points for discrete models
default_tfinal = 5 # Default simulation horizon
total_cycles = 5 # number of cycles for oscillating modes
pts_per_cycle = 25 # Number of points divide a period of oscillation
log_decay_percent = np.log(100) # Factor of reduction for real pole decays
# if a static model is given, don't bother with checks
if sys._isgain:
if sys._isdiscrete:
return sys._dt * min_points_z, sys._dt
else:
return default_tfinal, default_tfinal / min_points
if sys._isdiscrete:
# System already has sampling fixed hence we can't fall into the same
# trap mentioned above. Just get nonintegrating slow modes together
# with the damping.
dt = sys._dt
tfinal = default_tfinal
p = eigvals(sys.a)
# Array Masks
# unstable
m_u = (np.abs(p) >= 1 + sqrt_eps)
p_u, p = p[m_u], p[~m_u]
if p_u.size > 0:
m_u = (p_u.real < 0) & (np.abs(p_u.imag) < sqrt_eps)
t_emp = np.max(log_decay_percent / np.abs(np.log(p_u[~m_u]) / dt))
tfinal = max(tfinal, t_emp)
# zero - negligible effect on tfinal
m_z = np.abs(p) < sqrt_eps
p = p[~m_z]
# Negative reals- treated as oscillary mode
m_nr = (p.real < 0) & (np.abs(p.imag) < sqrt_eps)
p_nr, p = p[m_nr], p[~m_nr]
if p_nr.size > 0:
t_emp = np.max(log_decay_percent / np.abs(
(np.log(p_nr) / dt).real))
tfinal = max(tfinal, t_emp)
# discrete integrators
m_int = (p.real - 1 < sqrt_eps) & (np.abs(p.imag) < sqrt_eps)
p_int, p = p[m_int], p[~m_int]
# pure oscillatory modes
m_w = (np.abs(np.abs(p) - 1) < sqrt_eps)
p_w, p = p[m_w], p[~m_w]
if p_w.size > 0:
t_emp = total_cycles * 2 * np.pi / np.abs(np.log(p_w) / dt).min()
tfinal = max(tfinal, t_emp)
if p.size > 0:
t_emp = log_decay_percent / np.abs((np.log(p) / dt).real).min()
tfinal = max(tfinal, t_emp)
if p_int.size > 0:
tfinal = tfinal * 5
# Make tfinal an integer multiple of dt
num_samples = tfinal // dt
if num_samples > max_points_z:
tfinal = dt * max_points_z
else:
tfinal = dt * num_samples
return tfinal, dt
# Improve conditioning via balancing and zeroing tiny entries
# See <w,v> for [[1,2,0], [9,1,0.01], [1,2,10*np.pi]] before/after balance
b, (sca, perm) = matrix_balance(sys.a, separate=True)
p, l, r = eig(b, left=True, right=True)
# Reciprocal of inner product <w,v> for each λ, (bound the ~infs by 1e12)
# G = Transfer([1], [1,0,1]) gives zero sensitivity (bound by 1e-12)
eig_sens = reciprocal(maximum(1e-12, einsum('ij,ij->j', l, r).real))
eig_sens = minimum(1e12, eig_sens)
# Tolerances
p[np.abs(p) < np.spacing(eig_sens * norm(b, 1))] = 0.
# Incorporate balancing to outer factors
l[perm, :] *= reciprocal(sca)[:, None]
r[perm, :] *= sca[:, None]
w, v = sys.c @ r, l.T.conj() @ sys.b
origin = False
# Computing the "size" of the response of each simple mode
wn = np.abs(p)
if np.any(wn == 0.):
origin = True
dc = zeros_like(p, dtype=float)
# well-conditioned nonzero poles, np.abs just in case
ok = np.abs(eig_sens) <= 1 / sqrt_eps
# the averaged t→∞ response of each simple λ on each i/o channel
# See, A = [[-1, k], [0, -2]], response sizes are k-dependent (that is
# R/L eigenvector dependent)
dc[ok] = norm(v[ok, :], axis=1) * norm(w[:, ok], axis=0) * eig_sens[ok]
dc[wn != 0.] /= wn[wn != 0] if is_step else 1.
dc[wn == 0.] = 0.
# double the oscillating mode magnitude for the conjugate
dc[p.imag != 0.] *= 2
# Now get rid of noncontributing integrators and simple modes if any
relevance = (dc > 0.1 * dc.max()) | ~ok
psub = p[relevance]
wnsub = wn[relevance]
tfinal, dt = [], []
ints = wnsub == 0.
iw = (psub.imag != 0.) & (np.abs(psub.real) <= sqrt_eps)
# Pure imaginary?
if np.any(iw):
tfinal += (total_cycles * 2 * np.pi / wnsub[iw]).tolist()
dt += (2 * np.pi / pts_per_cycle / wnsub[iw]).tolist()
# The rest ~ts = log(%ss value) / exp(Re(λ)t)
texp_mode = log_decay_percent / np.abs(psub[~iw & ~ints].real)
tfinal += texp_mode.tolist()
dt += minimum(texp_mode / 50,
(2 * np.pi / pts_per_cycle / wnsub[~iw & ~ints])).tolist()
# All integrators?
if len(tfinal) == 0:
return default_tfinal * 5, default_tfinal * 5 / min_points
tfinal = np.max(tfinal) * (5 if origin else 1)
dt = np.min(dt)
dt = tfinal / max_points if tfinal // dt > max_points else dt
tfinal = dt * min_points if tfinal // dt < min_points else tfinal
return tfinal, dt
if len(V[i]) == n-1:
return True
return False
print(testH(exemple1, 7))
print(testH(exemple2, 5))
print(testH(exemple3, 4))
# ##Partie 3
# In[26]:
import scipy.linalg as lg
print(lg.eigvals(A1))
# ##Partie 6
# In[28]:
exemple4 = [[1,4], [0,2], [1,3], [2,4], [0,3]]
# In[34]:
def graphe(p):
V = [[1, 4], [0, 2], [1, 3], [2, 4], [0, 3]]
n = 5
for k in range(p):
def test_simple(self):
a = [[1, 2, 3], [1, 2, 3], [2, 5, 6]]
w = eigvals(a)
exact_w = [(9 + sqrt(93)) / 2, 0, (9 - sqrt(93)) / 2]
assert_array_almost_equal(w, exact_w)
# === Define the prior density === #
Sigma = [[0.9, 0.3], [0.3, 0.9]]
Sigma = np.array(Sigma)
x_hat = np.array([8, 8])
# === Initialize the Kalman filter === #
kn = Kalman(A, G, Q, R)
kn.set_state(x_hat, Sigma)
# === Set the true initial value of the state === #
x = np.zeros(2)
# == Print eigenvalues of A == #
print("Eigenvalues of A:")
print(eigvals(A))
# == Print stationary Sigma == #
S, K = kn.stationary_values()
print("Stationary prediction error variance:")
print(S)
# === Generate the plot === #
T = 50
e1 = np.empty(T)
e2 = np.empty(T)
for t in range(T):
# == Generate signal and update prediction == #
y = multivariate_normal(mean=np.dot(G, x), cov=R)
kn.update(y)
# == Update state and record error == #
# Initialize system parameters and matrices
f = 1.0 # Spring Constant
m1 = 0.4
m2 = 1.0
F = lambda q: np.array([[2 * f, -f, 0, -f * np.exp(-1j * q)], [
-f, 2 * f, -f, 0
], [0, -f, 2 * f, -f], [-f * np.exp(1j * q), 0, -f, 2 * f]])
M = np.diag([m1, m1, m1, m2])
# Set-up eigenvalue matrix
eig_mat = lambda q: inv(M).dot(F(q))
# Plot eigenvalues (normal mode frequencies) as a function of wavenumber
x_axis = np.arange(-np.pi, np.pi, np.pi / 50)
eigenlist = [eigvals(eig_mat(x)) for x in x_axis]
eigenlist_2 = np.sqrt(np.abs(eigenlist))
# Figure 2.12: Frequencies of the four eigenmodes of the linear chain.
plt.figure(1)
plt.plot(x_axis, eigenlist_2, "k.")
plt.xticks([-np.pi, -np.pi / 2, 0, np.pi / 2, np.pi],
[r"$-\pi$", r"$-\frac{\pi}{2}$", "0", r"$\frac{\pi}{2}$", r"$\pi$"])
plt.xlabel('q', size='xx-large')
plt.ylabel(r'$\omega$', size='xx-large')
plt.show()
# Print eigenvectors for q = 0
eigen_sys = eig(eig_mat(0.0))
omega = np.sqrt(np.abs(eigen_sys[0])) # Normal Mode Frequencies
eigen_vecs = np.abs(eigen_sys[1]) # Eigenvectors
def get_ergodic(F: np.ndarray, Q: np.ndarray, B: np.ndarray=None,
x_0: np.ndarray=None, force_diffuse: List[bool]=None,
is_warning: bool=True) -> Tuple[np.ndarray, np.ndarray]:
"""
Calculate initial state covariance matrix, and identify
diffuse state. It effectively solves a Lyapuov equation
Parameters:
----------
F : state transition matrix
Q : initial error covariance matrix
B : regression matrix
x_0 : initial x, used for calculating ergodic mean
force_diffuse : List of booleans of user-determined diffuse state
is_warning : whether to show warning message
Returns:
----------
P_0 : the initial state covariance matrix, np.inf for diffuse state
xi_0 : the initial state mean, 0 for diffuse state
"""
Q_ = Q.copy()
dim = Q.shape[0]
# Is is_diffuse is not supplied, create the list
if force_diffuse is None:
is_diffuse = np.zeros(dim, dtype=np.bool)
else:
is_diffuse = deepcopy(force_diffuse)
if len(is_diffuse) != dim:
raise ValueError('is_diffuse has wrong size')
# Check F and Q
if F.shape[0] != F.shape[1]:
raise TypeError('F must be a square matrix')
if Q.shape[0] != Q.shape[1]:
raise TypeError('Q must be a square matrix')
if F.shape[0] != Q.shape[0]:
raise TypeError('Q and F must be of same size')
# If explosive roots, use fully diffuse initialization
# and issue a warning
eig = linalg.eigvals(F)
if np.any(np.abs(eig) > 1):
if is_warning:
warnings.warn('Ft contains explosive roots. Assumptions ' + \
'of marginal LL correction may be violated, and ' + \
'results may be biased or inconsistent. Please provide ' + \
'user-defined xi_1_0 and P_1_0.', RuntimeWarning)
is_diffuse_explosive = get_explosive_diffuse(F)
is_diffuse = is_diffuse | is_diffuse_explosive
# Modify Q_ to reflect diffuse states
Q_ = mask_nan(is_diffuse, Q_, diag=inf_val)
# Calculate raw P_0
with warnings.catch_warnings():
warnings.simplefilter("ignore")
P_0 = lyap(F, Q_, 'bilinear')
# Clean up P_0
for i in range(dim):
if np.abs(P_0[i][i]) > max_val:
is_diffuse[i] = True
P_0 = mask_nan(is_diffuse, P_0, diag=0)
# Enforce PSD
P_0_PSD = get_nearest_PSD(P_0)
# Add nan to diffuse diagonal values
P_0_PSD += np.diag(np.array([np.nan if i else 0 for i in is_diffuse]))
# Compute ergodic mean
if B is None or x_0 is None:
Bx = np.zeros([dim, 1])
else:
if B.shape[0] != dim:
raise ValueError('B has the wrong dimension')
Bx = B.dot(x_0)
Bx[is_diffuse] = 0
F_star = F.copy()
F_star[is_diffuse] = 0
xi_0 = inv(np.eye(dim) - F_star).dot(Bx)
return P_0_PSD, xi_0
def find_zeros_and_poles_(self,
eps_reg=1e-15,
eps_stop=1e-10,
P_estimate=0,
pprint=False):
"""
Find the zeros and poles of a complex function (C->C) inside a closed curve.
input:
-fun: callable, the function of which the poles have to be found
-dfun: callable, the derivative of the function
-contours: list of callables, the contours (R->C) that constitute
a closed curve in the complex plane
-dcontours: list of callables, the derivatives (R->C) of the
respective contours
-t_params: list of arrays, the parametrizations of the contours
!!! Hard to get stopping right !!!
"""
# total multiplicity of zeros (number of zeros * order)
pol_unity = monicPolynomial([])
p_unity = pol_unity.f_polynomial()
s0 = int(round(self.inner_prod(p_unity, p_unity).real))
N = s0 + 2 * P_estimate
if pprint: print('N =', N)
# list of FOPs
phis = []
pols = []
phis.append(p_unity)
pols.append(pol_unity) # phi_0
# if s0 is zero
if s0 == 0:
n = 0
# arithmetic mean of nodes is zero
mu = 0.
pol = monicPolynomial([0.])
phis.append(pol.f_polynomial())
pols.append(pol) # phi_1
zeros = np.array([])
r = 0
t = 1
else:
# compute arithmetic mean of nodes
p_aux = monicPolynomial([0.]).f_polynomial()
mu = self.inner_prod(p_unity, p_aux) / N
if pprint: print('mu =', mu)
# append first polynomial
pol = monicPolynomial([-mu])
phis.append(pol.f_polynomial())
pols.append(pol) # phi_1
# if the algorithm quits after the first zero, it is mu
zeros = np.array([mu])
n = 1
# initialization
r = 1
t = 0
while r + t < N:
if pprint: print('1.')
# naive criterion to check if phi_r+t+1 is regular
prod_aux, maxpsum = self.inner_prod(phis[-1],
phis[-1],
compute_maxpsum=True)
# compute eigenvalues of the next pencil
G, G1 = self.generalized_hankel_matrices(phis, pols)
eigv = la.eigvals(G1, G)
# check if these eigenvalues lie within the contour
if self.points_within_contour(eigv + mu):
# if np.abs(prod_aux)/maxpsum > eps_reg:
if pprint: print('1.1')
# compute next FOP in the regular way
pol = monicPolynomial(eigv, coef_type='zeros')
phis.append(pol.f_polynomial())
pols.append(pol)
r += t + 1
t = 0
allsmall = True
tau = 0
while allsmall and (r + tau) < N:
if pprint: print('1.1.1')
# if all further inner porducts are zero
taupol = npol.polyfromroots([mu for _ in range(tau)])
tauphi = monicPolynomial(
npol.polymul(taupol, pols[-1].coef),
coef_type='normal').f_polynomial()
ip, maxpsum = self.inner_prod(tauphi,
phis[r],
compute_maxpsum=True)
tau += 1
if np.abs(ip) / maxpsum > eps_stop:
allsmall = False
if allsmall:
if pprint: print('1.1.2: STOP')
n = r
zeros = eigv + mu
t = N # STOP
else:
if pprint: print('1.2')
c = npol.polyfromroots([mu])
pol = monicPolynomial(npol.polymul(c, pols[-1].coef),
coef_type='normal')
pols.append(pol)
phis.append(pol.f_polynomial())
t += 1
# check multiplicities
# constuct vandermonde system
A = np.vander(zeros).T[::-1, :]
b = np.array(
[self.inner_prod(p_unity, lambda x, k=k: x**k) for k in range(n)])
# solve the Vandermonde system
nu = la.solve(A, b)
nu = np.round(nu).real.astype(int)
# for printing result
if pprint:
print('>>> Result of computation of zeros <<<')
print('number of zeros = ', n - len(np.where(nu == 0)[0]))
for i, zero in enumerate(zeros):
print('zero #' + str(i + 1) + ' = ' + str(zero) +
' (multiplicity = ' + str(nu[i]) + ')')
print('')
# eliminate spurious zeros (the ones with zero multiplicity)
inds = np.where(nu > 0)[0]
return zeros[inds], n, nu[inds]
def ft(theta: np.ndarray, f: Callable, T: int, x_0: np.ndarray=None,
xi_1_0: np.ndarray=None, P_1_0: np.ndarray=None,
force_diffuse: List[bool]=None, is_warning: bool=True,
const_M_type: str='simple') -> Dict:
"""
Duplicate arrays in M = f(theta) and generate list of Mt
Output of f(theta) must contain all the required keys.
Parameters:
----------
theta : input of f(theta). Underlying parameters to be optimized
f : obtained from get_f. Mapping theta to M
T : length of Mt. "Duplicate" M for T times
x_0 : establish initial state mean
xi_1_0 : specify initial state mean. override calculated mean
P_1_0 : initial state cov
force_diffuse : use-defined diffuse state
is_warning : whether to display the warning about explosive roots
const_M_type : type of list of constant matrices, default as 'simple'
Returns:
----------
Mt : system matrices for a BSTS. Should contain
all the required keywords.
"""
M = f(theta)
# If a value is close to 0 or inf, set them to 0 or inf
# If an array is 1D, convert it to 2D
for key in M.keys():
if M[key].ndim < 2:
M[key] = M[key].reshape(1, -1)
M[key] = clean_matrix(M[key])
# Check validity of M
required_keys = set(['F', 'H', 'Q', 'R'])
M_keys = set(M.keys())
if len(required_keys - M_keys) > 0:
raise ValueError('f does not have required outputs: {}'.
format(required_keys - M_keys))
# Check dimensions of M
for key in M_keys:
if len(M[key].shape) < 2:
raise TypeError('System matrices must be 2D')
# Check PSD of R and Q
if np.array_equal(M['Q'], M['Q'].T):
eig_Q = linalg.eigvals(M['Q'])
if not np.all(eig_Q >= 0):
raise ValueError('Q is not semi-PSD')
else:
raise ValueError('Q is not symmetric')
if np.array_equal(M['R'], M['R'].T):
eig_R = linalg.eigvals(M['R'])
if not np.all(eig_R >= 0):
raise ValueError('R is not semi-PSD')
else:
raise ValueError('R is not symmetric')
# Generate ft for required keys
Ft = build_tensor(M['F'], T)
Ht = build_tensor(M['H'], T)
Qt = build_tensor(M['Q'], T)
Rt = build_tensor(M['R'], T)
# Set Bt if Bt is not Given
if 'B' not in M_keys:
dim_xi = M['F'].shape[0]
if 'D' not in M_keys:
M.update({'B': np.zeros((dim_xi, 1))})
else:
dim_x = M['D'].shape[1]
M.update({'B': np.zeros((dim_xi, dim_x))})
if 'D' not in M_keys:
dim_x = M['B'].shape[1] # B is already defined
dim_y = M['H'].shape[0]
M.update({'D': np.zeros((dim_y, dim_x))})
# Get Bt and Dt for ft
Bt = build_tensor(M['B'], T)
Dt = build_tensor(M['D'], T)
# Initialization
if P_1_0 is None or xi_1_0 is None:
P_1_0, xi_1_0 = get_ergodic(M['F'], M['Q'], M['B'],
x_0=x_0, force_diffuse=force_diffuse,
is_warning=is_warning)
Mt = {'Ft': Ft,
'Bt': Bt,
'Ht': Ht,
'Dt': Dt,
'Qt': Qt,
'Rt': Rt,
'xi_1_0': xi_1_0,
'P_1_0': P_1_0}
return Mt
def _numeric_nullspace_dim(mat):
"""Numerically computes the nullspace dimension of a matrix."""
mat_numeric = np.array(mat.evalf().tolist(), dtype=complex)
eigenvals = la.eigvals(mat_numeric)
return np.sum(np.isclose(eigenvals, np.zeros_like(eigenvals)))
m = np.mat('0 1 2; 1 0 3; 4 -3 8')
print(sla.det(m)) # scipy.linalg
print(nla.det(m)) # numpy.linalg
# 7.8.2 求解逆矩阵
m = np.mat('0 1 2; 1 0 3; 4 -3 8')
print(m.I) # 矩阵对象的逆矩阵属性
print(m * m.I) # 矩阵和其逆矩阵的乘积为单位矩阵
print(sla.inv(m)) # scipy.linalg
print(nla.inv(m)) # numpy.linalg
# 7.8.3 计算特征向量和特征值
A = np.mat('0 1 2; 1 0 3; 4 -3 8') # 生成3阶矩阵
print(sla.eigvals(A)) # 返回3个特征值
print(sla.eig(A)) # 返回3个特征值和3个特征向量组成的元组
print(nla.eigvals(A)) # 返回3个特征值
print(nla.eig(A)) # 返回3个特征值和3个特征向量组成的元组
# 7.8.4 矩阵的奇异值分解
A = np.mat(np.random.randint(0, 10, (3, 4)))
print(A)
u, s, v = sla.svd(A)
print(u.shape, s.shape, v.shape)
print(u)
print(s)
print(v)
def crDist(cr0, cr1):
eigv = eigh.eigvals(cr0, cr1)
sum = 0
for val in eigv:
sum += pow(math.log(abs(val), math.e), 2)
return math.sqrt(sum)