def chi_norm(emg_data, params):
emg_data = norm_emg(emg_data)
emg_data = np.abs(emg_data)
#emg_data = norm_emg(emg_data)
for chnl in range(len(emg_data)):
arg = params[chnl][:-2]
loc = params[chnl][-2]
scale = params[chnl][-1]
a_max = chi.ppf(0.9999999999999999, loc=loc, scale=scale, *arg)
a_min = chi.ppf(0.00000000001, loc=loc, scale=scale, *arg)
transf = np.clip(emg_data[chnl, :], a_min=a_min, a_max=a_max)
transf = chi.cdf(transf, loc=loc, scale=scale, *arg)
emg_data[chnl] = norm.ppf(transf)
return emg_data
def wald_test(tau, Sigma, alpha=0.05, max_condition=1e-6, pval=False):
"""
Test based on the chi_d distribution.
:param tau: observed test statistics (scaled with sqrt(n)
:param Sigma: observed covariance matrix
:param alpha: level of the test
:param max_condition: determines at which threshold eigenvalues are considered as 0
:param pval: if true, returns the conditional p value instead of the test result
:return: level of the test
"""
# instead of regularizing we preprocess Sigma and tau to get rid of 0 eigenvalues
tau, Sigma = preprocessing(tau, Sigma, max_condition=max_condition)
d = len(tau)
# compute matrix inverse
Sigma_inv = np.linalg.inv(Sigma)
# below quantity is asymptotically standard normal
t_obs = np.sqrt(tau @ Sigma_inv @ tau)
# compute the 1-alpha quantile of the chi distribution with d degrees of freedom
threshold = chi.ppf(q=1-alpha, df=d)
if not pval:
if t_obs > threshold:
return 1
else:
return 0
else:
# return p value
return 1 - chi.cdf(x=t_obs, df=d)
def estimate_sigma(observed, df, upper_bound, factor=3, npts=50, nsample=2000):
"""
Produce an estimate of $\sigma$ from a constrained
error sum of squares. The relevant distribution is a
scaled $\chi^2$ restricted to $[0,U]$ where $U$ is `upper_bound`.
Parameters
----------
observed : float
The observed sum of squares.
df : float
Degrees of freedom of the sum of squares.
upper_bound : float
Upper limit of truncation interval.
factor : float
Range of candidate values is
[observed/factor, observed*factor]
npts : int
How many candidate values for interpolator.
nsample : int
How many samples for each expected value
of the truncated sum of squares.
Returns
-------
sigma_hat : np.float
Estimate of $\sigma$.
"""
values = np.linspace(1. / factor, factor, npts) * observed
expected = 0 * values
for i, value in enumerate(values):
P_upper = chidist.cdf(upper_bound * np.sqrt(df) / value, df)
U = np.random.sample(nsample)
sample = chidist.ppf(P_upper * U, df) * value
expected[i] = np.mean(sample**2)
if expected[i] >= 1.1 * (observed**2 * df + observed**2 * df**(0.5)):
break
interpolant = interp1d(values, expected + df**(0.5) * values**2)
V = np.linspace(1. / factor, factor, 10 * npts) * observed
# this solves for the solution to
# expected(sigma) + sqrt(df) * sigma^2 = observed SS * (1 + sqrt(df))
# the usual "MAP" estimator would have RHS just observed SS
# but this factor seems to ``correct it''.
# it is such that if there were no selection it would be
# the usual unbiased estimate
sigma_hat = np.min(
V[interpolant(V) >= observed**2 * df + observed**2 * df**(0.5)])
return sigma_hat
def _quantile_notTruncated(self, q, tol=1.e-6):
"""
Compute the quantile for the non truncated distribution
Parameters
----------
q : float
quantile you want to compute. Between 0 and 1
tol : float
precision for the output
Returns
-------
x : float
x such that P(X < x) = q
"""
scale = self._scale
k = self._k
dps = self._dps
z_approx = scale * chi.ppf(q, k)
epsilon = scale * 0.001
lb = z_approx - epsilon
ub = z_approx + epsilon
f = lambda z: self._cdf_notTruncated(-np.inf, z, dps)
z = find_root(f, q, lb, ub, tol)
return z
def _quantile_notTruncated(self, q, tol=1.e-6):
"""
Compute the quantile for the non truncated distribution
Parameters
----------
q : float
quantile you want to compute. Between 0 and 1
tol : float
precision for the output
Returns
-------
x : float
x such that P(X < x) = q
"""
scale = self._scale
k = self._k
dps = self._dps
z_approx = scale * chi.ppf(q, k)
epsilon = scale * 0.001
lb = z_approx - epsilon
ub = z_approx + epsilon
f = lambda z: self._cdf_notTruncated(-np.inf, z, dps)
z = find_root(f, q, lb, ub, tol)
return z
def estimate_sigma(observed, df, upper_bound, factor=3, npts=50, nsample=2000):
"""
Produce an estimate of $\sigma$ from a constrained
error sum of squares. The relevant distribution is a
scaled $\chi^2$ restricted to $[0,U]$ where $U$ is `upper_bound`.
Parameters
----------
observed : float
The observed sum of squares.
df : float
Degrees of freedom of the sum of squares.
upper_bound : float
Upper limit of truncation interval.
factor : float
Range of candidate values is
[observed/factor, observed*factor]
npts : int
How many candidate values for interpolator.
nsample : int
How many samples for each expected value
of the truncated sum of squares.
Returns
-------
sigma_hat : np.float
Estimate of $\sigma$.
"""
values = np.linspace(1./factor, factor, npts) * observed
expected = 0 * values
for i, value in enumerate(values):
P_upper = chidist.cdf(upper_bound * np.sqrt(df) / value, df)
U = np.random.sample(nsample)
sample = chidist.ppf(P_upper * U, df) * value
expected[i] = np.mean(sample**2)
if expected[i] >= 1.1 * (observed**2 * df + observed**2 * df**(0.5)):
break
interpolant = interp1d(values, expected + df**(0.5) * values**2)
V = np.linspace(1./factor,factor,10*npts) * observed
# this solves for the solution to
# expected(sigma) + sqrt(df) * sigma^2 = observed SS * (1 + sqrt(df))
# the usual "MAP" estimator would have RHS just observed SS
# but this factor seems to ``correct it''.
# it is such that if there were no selection it would be
# the usual unbiased estimate
sigma_hat = np.min(V[interpolant(V) >= observed**2 * df + observed**2 * df**(0.5)])
return sigma_hat
def mean_min_dists(X, y):
"""
Calculate min distances used for original bolstering sig, 1-sigma.
X -> nxD dataset
y -> label
output -> sig11(1xd), sig12(1x(D-d)), sig21(1xd), sig22(1x(D-d)), Four sigmas for two class, with in each class ONE sigma for first d features and the other for the rest of D-d features.
"""
from scipy.stats import chi
ind1 = y == 0
ind2 = y == 1
X1 = X[ind1]
X2 = X[ind2]
n = X.shape[0]
p = X.shape[1]
n1 = X1.shape[0]
n2 = X2.shape[0]
tmp1 = np.zeros(n1)
tmp2 = np.zeros(n2)
for i in range(n1):
dm = sys.float_info.max
for j in range(i):
e = X1[i] - X1[j]
d = np.dot(e, e.T)
if d < dm:
dm = d
for j in range(i + 1, n1):
e = X1[i] - X1[j]
d = np.dot(e, e.T)
if d < dm:
dm = d
tmp1[i] = np.sqrt(dm)
d1 = np.mean(tmp1)
for i in range(n2):
dm = sys.float_info.max
for j in range(i):
e = X2[i] - X2[j]
d = np.dot(e, e.T)
if d < dm:
dm = d
for j in range(i + 1, n2):
e = X2[i] - X2[j]
d = np.dot(e, e.T)
if d < dm:
dm = d
tmp2[i] = np.sqrt(dm)
d2 = np.mean(tmp2)
cp = chi.ppf(PERCENTILE, p)
sig1 = d1 * np.ones(p) / cp
sig2 = d2 * np.ones(p) / cp
return np.vstack((sig1, sig2))
def test_chi(self):
from scipy.stats import chi
import matplotlib.pyplot as plt
fig, ax = plt.subplots(1, 1)
df = 78
mean, var, skew, kurt = chi.stats(df, moments='mvsk')
x = np.linspace(chi.ppf(0.01, df), chi.ppf(0.99, df), 100)
ax.plot(x, chi.pdf(x, df), 'r-', lw=5, alpha=0.6, label='chi pdf')
rv = chi(df)
ax.plot(x, rv.pdf(x), 'k-', lw=2, label='frozen pdf')
vals = chi.ppf([0.001, 0.5, 0.999], df)
np.allclose([0.001, 0.5, 0.999], chi.cdf(vals, df))
r = chi.rvs(df, size=1000)
ax.hist(r, density=True, histtype='stepfilled', alpha=0.2)
ax.legend(loc='best', frameon=False)
self.assertEqual(str(ax), "AxesSubplot(0.125,0.11;0.775x0.77)")
def mvstdtprob(a, b, R, df, ieps=1e-5, quadkwds=None, mvstkwds=None):
'''probability of rectangular area of standard t distribution
assumes mean is zero and R is correlation matrix
Notes
-----
This function does not calculate the estimate of the combined error
between the underlying multivariate normal probability calculations
and the integration.
'''
kwds = dict(args=(a, b, R, df), epsabs=1e-4, epsrel=1e-2, limit=150)
if not quadkwds is None:
kwds.update(quadkwds)
#print kwds
res, err = integrate.quad(funbgh2, *chi.ppf([ieps, 1 - ieps], df), **kwds)
prob = res * bghfactor(df)
return prob
def mvstdtprob(a, b, R, df, ieps=1e-5, quadkwds=None, mvstkwds=None):
"""
Probability of rectangular area of standard t distribution
assumes mean is zero and R is correlation matrix
Notes
-----
This function does not calculate the estimate of the combined error
between the underlying multivariate normal probability calculations
and the integration.
"""
kwds = dict(args=(a, b, R, df), epsabs=1e-4, epsrel=1e-2, limit=150)
if quadkwds is not None:
kwds.update(quadkwds)
lower, upper = chi.ppf([ieps, 1 - ieps], df)
res, err = integrate.quad(funbgh2, lower, upper, **kwds)
prob = res * bghfactor(df)
return prob
def min_dists_Dsigma(X, y):
"""
Calculate min distances used for new bolstering sig, D-sigma.
X -> nxD dataset
y -> label
output -> sig1, sig2, for D directions of class 1 and 2.
"""
from scipy.stats import chi
ind1 = y == 0
ind2 = y == 1
X1 = X[ind1]
X2 = X[ind2]
n = X.shape[0]
D = X.shape[1]
X1.sort(axis=0)
X2.sort(axis=0)
cp = chi.ppf(PERCENTILE, 1) # degree of one, for every dimention
sig1 = np.mean(abs(X1[1:] - X1[:-1]), axis=0) / cp
sig2 = np.mean(abs(X2[1:] - X2[:-1]), axis=0) / cp
return np.vstack((sig1, sig2))
def estimate_g(radii, data_dimensionality, cdf_extension, cdf_precision):
"""
Estimates the function g() which is used in a rescaling of the vectors
Parameters
----------
radii : ndarray
A 1d array with n elements where n is the number of samples in the dataset
and each entry is the l2 norm of the representation for that sample
data_dimensionality : int
The dimensionality of the datapoints that the radii pertains to. Used to
set the degrees of freedom on the chi distribution
cdf_extension : float
The amount by which to extend the support of the CDF as a fraction of the
range of radii present in the provided samples
cdf_precision : int
The number of samples to devote to evaluating the CDF in the range between
the maximum and minimum radii
Returns
-------
g_support : ndarray
A 1d array giving the values of r (radius) at which g has been
estimated
g : ndarray
A 1d array giving the value of g for each value in the support
"""
g_support, cdf = estimate_radial_CDF(radii, cdf_extension, cdf_precision)
# the l2 norm of a vector of n iid normal random variables is
# a random variable distributed as a chi distribution with n degrees of freedom
# we want it's inverse CDF, or percent point function
# Because feeding the inverse CDF a value of 1.0 will produce inf, we'll just
# hackily fix this, slightly lowering the top value of the cdf
cdf[cdf == 1.0] = cdf[cdf == 1.0] - (1. / len(radii))
g = chi.ppf(cdf, data_dimensionality)
return g_support, g
print(res.wald_test_terms())
# Chi2 это КСИ КВАДРАТ https://en.wikipedia.org/wiki/Chi-squared_distribution
# chi2 P>chi2 df constraint
# Intercept 1.022117 0.31201739467110934 1
# sex 54.473978 1.5751991092226142e-13 1
# class_1 46.947935 7.289775024150576e-12 1
# class_2 33.212807 8.260467771755613e-09 1
# sex:class_1 21.853960 2.9420881191443115e-06 1
# sex:class_2 33.535868 6.996184344418819e-09 1
# В столбце сhi2 значение функции кси-квадрат а в P>chi2 критическое значение
# отношения правдоподобия
LR = 2 * (loglikelihood_logit_2 - loglikelihood_logit_1)
chi_crit = chi.ppf(0.95, 2)
print(
'статистика отношения правдоподобия {}, критическое знание chi^2(0.95,2) {}'
.format(LR, chi_crit))
if chi_crit < LR:
print(
'Отвергаем гипотзу о H0:(b4=b5=0) на основание теста отношнения правдоподобия'
)
else:
print(
'Принимаем гипотзу о H0:(b4=b5=0) на основание теста отношнения правдоподобия'
)
###################################################################################################
############### Возможно, вклад пола в шансы выживания зависел от класса #####################
def estimate_sigma(observed, truncated_df, lower_bound, upper_bound, untruncated_df=0, factor=3, npts=50, nsample=2000):
"""
Produce an estimate of $\sigma$ from a constrained
error sum of squares. The relevant distribution is a
scaled $\chi^2$ restricted to $[0,U]$ where $U$ is `upper_bound`.
Parameters
----------
observed : float
The observed sum of squares.
truncated_df : float
Degrees of freedom of the truncated $\chi^2$ in the sum of squares.
The observed sum is assumed to be the sum
of an independent untruncated $\chi^2$ and the truncated one.
lower_bound : float
Lower limit of truncation interval.
upper_bound : float
Upper limit of truncation interval.
untruncated_df : float
Degrees of freedom of the untruncated $\chi^2$ in the sum of squares.
factor : float
Range of candidate values is
[observed/factor, observed*factor]
npts : int
How many candidate values for interpolator.
nsample : int
How many samples for each expected value
of the truncated sum of squares.
Returns
-------
sigma_hat : np.float
Estimate of $\sigma$.
"""
if untruncated_df < 50:
linear_term = truncated_df**(0.5)
else:
linear_term = 0
total_df = untruncated_df + truncated_df
values = np.linspace(1./factor, factor, npts) * observed
expected = 0 * values
for i, value in enumerate(values):
P_upper = chidist.cdf(upper_bound * np.sqrt(truncated_df) / value, truncated_df)
P_lower = chidist.cdf(lower_bound * np.sqrt(truncated_df) / value, truncated_df)
U = np.random.sample(nsample)
if untruncated_df > 0:
sample = (chidist.ppf((P_upper - P_lower) * U + P_lower, truncated_df)**2 + chidist.rvs(untruncated_df, size=nsample)**2) * value**2
else:
sample = (chidist.ppf((P_upper - P_lower) * U + P_lower, truncated_df) * value)**2
expected[i] = np.mean(sample)
if expected[i] >= 1.5 * (observed**2 * total_df + observed**2 * linear_term):
break
interpolant = interp1d(values, expected + values**2 * linear_term)
V = np.linspace(1./factor,factor,10*npts) * observed
# this solves for the solution to
# expected(sigma) + sqrt(df) * sigma^2 = observed SS * (1 + sqrt(df))
# the usual "MAP" estimator would have RHS just observed SS
# but this factor seems to correct it.
# it is such that if there were no selection it would be
# the usual unbiased estimate
try:
sigma_hat = np.min(V[interpolant(V) >= observed**2 * total_df + observed**2 * linear_term])
except ValueError:
# no solution, just return observed
sigma_hat = observed
return sigma_hat
significancia = 0.05
confianca = 1 - significancia
k = 2 # Número de eventos possíveis
graus_de_liberdade = k - 1
# Passo 1 - formulação das hipóteses H_0 e H_1
# H_0: F_{CARA} = F_{COROA}
# H_1: F_{CARA} \neq F_{COROA}
# Passo 2 - fixação da significância do teste (\alpha)
from scipy.stats import chi
# chi_{\alpha}^2
chi_2_alpha = chi.ppf(confianca, graus_de_liberdade)**2
chi_2_alpha
# Passo 3 - cálculo da estatística-teste e verificação desse valor com as áreas de aceitação e rejeição do teste
# \chi^2 = \sum_{i=1}^{k}{\frac{(F_{i}^{Obs} - F_{i}^{Esp})^2}{F_{i}^{Esp}}}
chi_2 = 0
for i in range(k):
chi_2 += (F_Observada[i] - F_Esperada[i])**2 / F_Esperada[i]
chi_2
# Passo 4 - Aceitação ou rejeição da hipótese nula
# Critério do valor crítico
# Rejeitar H_0 se \chi_{teste}^2 > \chi_{\alpha}^2
def ost_test(tau,
Sigma,
alpha=0.05,
selection='discrete',
max_condition=1e-6,
accuracy=1e-6,
constraints='Sigma',
pval=False):
"""
Runs the full test suggested in our paper.
:param tau: observed statistic
:param Sigma: covariance matrix
:param alpha: level of test
:param selection: continuous/discrete (discrete is not extensively tested)
:param max_condition: at which condition number the covariance matrix is truncated.
:param accuracy: threshold to determine whether an entry is zero
:param constraints: if 'Sigma' we work with the constraints (Sigma beta) >=0. If 'positive' we work with beta >= 0
:param pval: if true, returns the conditional p value instead of the test result
:return: 1 (reject), 0 (no reject)
"""
assert constraints == 'Sigma' or constraints == 'positive', 'Constraints are not implemented'
# if the selection is discrete we dont want any transformations
if selection == 'discrete':
constraints = 'positive'
# check if there are entries with 0 variance
zeros = [i for i in range(len(tau)) if Sigma[i][i] < 1e-10]
tau = np.delete(tau, zeros)
Sigma = np.delete(Sigma, zeros, 0)
Sigma = np.delete(Sigma, zeros, 1)
if constraints == 'Sigma':
# compute pseudoinverse to also handle singular covariances (see Appendix)
r_cond = max_condition # parameter which precision to use
Sigma_inv = np.linalg.pinv(Sigma, rcond=r_cond, hermitian=True)
# use Remark 1 to convert the problem
tau = Sigma_inv @ tau
Sigma = Sigma_inv
# Apply Theorem 1 in the canonical form with beta>=0 constraints
beta_star = optimization(tau=tau, Sigma=Sigma, selection=selection)
# determine active set
non_zero = [1 if beta_i > accuracy else 0 for beta_i in beta_star]
projector = np.diag(non_zero)
effective_sigma = projector @ Sigma @ projector
# Use the rank of effective Sigma to determine how many degrees of freedom the covariance has after conditioning
# for non-singular original covariance, this is the same number as the number of active dimensions |mathcal{U}|,
# however, for singular cases using the rank is the right way to go.
tol = max_condition * np.max(np.linalg.eigvalsh(Sigma))
r = np.linalg.matrix_rank(effective_sigma, tol=tol, hermitian=True)
# go back to notation used in the paper
l = r
if l > 1:
test_statistic = beta_star @ tau / np.sqrt(
beta_star @ Sigma @ beta_star)
threshold = chi_stats.ppf(q=1 - alpha, df=l)
else:
vminus = truncation(beta_star=beta_star,
tau=tau,
Sigma=Sigma,
accuracy=accuracy)
threshold = truncated_gaussian(var=beta_star @ Sigma @ beta_star,
v_minus=vminus,
level=alpha)
test_statistic = beta_star @ tau
if not pval:
if test_statistic > threshold:
# reject
return 1
else:
# cannot reject
return 0
if pval:
if l > 1:
test_statistic = beta_star @ tau / np.sqrt(
beta_star @ Sigma @ beta_star)
pvalue = 1 - chi_stats.cdf(x=test_statistic, df=l)
else:
test_statistic = beta_star @ tau / np.sqrt(
beta_star @ Sigma @ beta_star)
vminus = truncation(beta_star=beta_star, tau=tau, Sigma=Sigma, accuracy=accuracy) / \
np.sqrt(beta_star @ Sigma @ beta_star)
pvalue = 1 - (norm.cdf(x=test_statistic) -
norm.cdf(x=vminus)) / (1 - norm.cdf(x=vminus))
return pvalue
def penconst_denoise(shape, scale, regularizer):
"""Computes a suggestion for the penalty constant of a denoising problem.
Assume that we have noisy observations of an operator :math:`\mathcal{A}`:
.. math:: \mathcal{Y} = \mathcal{A} + \mathcal{W},
where :math:`\mathcal{W}` is Gaussian noise with scale :math:`\sigma`.
To denoise this operator with the nuclear norm :math:`N` as a regularizer,
we solve
.. math::
\operatorname{minimize}_\mathcal{X} \Vert \mathcal{X} - \mathcal{Y} \Vert^2_F +
\lambda N(\mathcal{X}).
The performance of the denoiser depends on the choice of :math:`\lambda >0`,
and we choose
.. math:: \lambda = \mathbb{E} N^*(\mathcal{W}),
where :math:`N^*` is the dual of the nuclear norm :math:`N`.
Note that this computation depends on the shape of :math:`\mathcal{A}`, the
noise level :math:`\sigma`, and the choice of the nuclear norm :math:`N`.
Note
----
Not all choices of the nuclear norm :math:`N` lead to efficient computations
of the dual norm :math:`N^*`. In cases where this computation is not
feasible, we return a heuristic guess.
Parameters
----------
shape : tuple
The shape of the operator to denoise.
scale : float
The standard deviation of the random Gaussian noise (:math:`\sigma`).
regularizer : Regularizer
The regularizer used in the denoising problem (:math:`N`)
Returns
-------
float
The suggested penalty constant (:math:`\lambda`).
"""
from scipy.stats import chi, gumbel_r, norm
def max_of_variates(n, ppf):
return gumbel_r.mean(loc=ppf(1 - 1.0 / (n + 1)),
scale=(ppf(1 - 1.0 / (np.e * (n + 1))) -
ppf(1 - 1.0 / (n + 1))))
def max_of_gaussians(n):
return max_of_variates(n, norm.ppf)
# Warnings and errors
def warn_guess():
print('warning: guess penconst for {0}'.format(regularizer))
def warn_default():
print('warning: default penconst for {0}'.format(regularizer))
return scale * (np.sqrt(lshape) + np.sqrt(rshape))
def error_value():
raise ValueError('Bad regularizer {0}'.format(regularizer))
lshape = shape[0] * shape[1] # total dimension of left factor
rshape = shape[2] * shape[3] # total dimension of right factor
lrank = min(shape[0:2])
rrank = min(shape[2:4])
if isinstance(regularizer, NucNorm):
lnorm = regularizer.lnorm
rnorm = regularizer.rnorm
# Choose appropriate penalty constant
if lnorm is norm_l1:
if rnorm is norm_l2:
out = scale * max_of_variates(lshape,
ppf=lambda q: chi.ppf(q, rshape))
elif rnorm is norm_l1:
# \ell_\infty norm of noise
out = scale * max_of_gaussians(
2 * np.prod(shape)
) # doubling because we want max of folded Gaussians --- maybe use chi instead? slower and probably not much difference
elif rnorm is norm_linf:
# max of \ell_1 norms of rows of noise
out = scale * np.mean([
np.max([
np.sum(np.abs(np.random.normal(size=(rshape))))
for i in range(lshape)
]) for j in range(1000)
])
elif rnorm is norm_s1:
# max of S_\infty norms of right factors
out = scale * np.mean([
np.max([
np.linalg.norm(np.random.normal(size=shape[2:4]),
ord=2) for j in range(lshape)
]) for i in range(1000)
])
elif rnorm is norm_sinf:
# max of S_1 norms of right factors
out = scale * np.mean([
np.max([
np.linalg.norm(np.random.normal(size=shape[2:4]),
ord='nuc') for j in range(lshape)
]) for i in range(1000)
])
else:
out = warn_default()
elif lnorm is norm_l2:
if rnorm is norm_l2:
# S_\infty norm of noise
out = scale * (np.sqrt(lshape) + np.sqrt(rshape))
elif rnorm is norm_l1:
# max of \ell_2 norm of columns of noise
out = scale * max_of_variates(rshape,
ppf=lambda q: chi.ppf(q, lshape))
elif rnorm is norm_linf:
# guess for \ell_2, \ell_infty
warn_guess()
out = scale * (np.sqrt(lshape) + np.sqrt(rshape)) * np.sqrt(
rshape) # SHAPE[2] correct?
elif rnorm is norm_sinf:
# guess for \ell_2, S_\infty
warn_guess()
out = scale * (np.sqrt(lshape) +
np.sqrt(rshape)) * np.sqrt(rrank)
else:
out = warn_default()
elif lnorm is norm_linf:
if rnorm is norm_linf:
# guess for \ell_\infty, \ell_\infty
warn_guess()
out = scale * (np.sqrt(lshape) + np.sqrt(rshape)) * np.sqrt(
lshape * rshape)
elif rnorm is norm_l1:
# max of \ell_1 norm of columns of noise
out = scale * np.mean([
np.max([
np.sum(np.abs(np.random.normal(size=(lshape))))
for i in range(rshape)
]) for j in range(1000)
])
elif rnorm is norm_l2:
# guess for \ell_\infty, \ell_2
warn_guess()
out = scale * (np.sqrt(lshape) +
np.sqrt(rshape)) * np.sqrt(lshape)
elif rnorm is norm_s1:
# guess for \ell_\infty, S_1
warn_guess()
out = scale * (np.sqrt(lshape) +
np.sqrt(rshape)) * np.sqrt(lshape)
elif rnorm is norm_sinf:
# guess for \ell_\infty, S_\infty
warn_guess()
out = scale * (np.sqrt(lshape) + np.sqrt(rshape)) * np.sqrt(
lshape * rrank)
else:
out = warn_default()
elif lnorm is norm_s1:
if rnorm is norm_l1:
# max of S_\infty norms of left factors
out = scale * np.mean([
np.max([
np.linalg.norm(np.random.normal(size=shape[0:2]),
ord=2) for j in range(rshape)
]) for i in range(1000)
])
elif rnorm is norm_linf:
# guess for S_1, \ell_\infty
warn_guess()
out = scale * (np.sqrt(lshape) +
np.sqrt(rshape)) * np.sqrt(rshape)
elif rnorm is norm_sinf:
# guess for S_1, S_\infty
warn_guess()
out = scale * (np.sqrt(lshape) +
np.sqrt(rshape)) * np.sqrt(rrank)
else:
out = warn_default()
elif lnorm is norm_sinf:
if rnorm is norm_l1:
# max of S_1 norms of left factors
out = scale * np.mean([
np.max([
np.linalg.norm(np.random.normal(size=shape[0:2]),
ord='nuc') for j in range(rshape)
]) for i in range(1000)
])
elif rnorm is norm_l2:
# guess for S_\infty, \ell_2
warn_guess()
out = scale * (np.sqrt(lshape) +
np.sqrt(rshape)) * np.sqrt(lrank)
elif rnorm is norm_linf:
# guess for S_\infty, \ell_\infty
warn_guess()
out = scale * (np.sqrt(lshape) + np.sqrt(rshape)) * np.sqrt(
lrank * rshape)
elif rnorm is norm_s1:
# guess for S_\infty, S_1
warn_guess()
out = scale * (np.sqrt(lshape) +
np.sqrt(rshape)) * np.sqrt(lrank)
elif rnorm is norm_sinf:
# guess for S_\infty, S_\infty
warn_guess()
out = scale * (np.sqrt(lshape) + np.sqrt(rshape)) * np.sqrt(
lrank * rrank)
else:
out = warn_default()
else:
out = warn_default()
elif isinstance(regularizer, VectorNorm) and regularizer.p == 'inf':
out = scale * np.mean([
np.sum(np.abs(np.random.normal(size=(np.prod(shape)))))
for i in range(1000)
])
elif isinstance(regularizer, MaxNorm):
# guess for max-norm
warn_guess()
out = scale * (np.sqrt(lshape) + np.sqrt(rshape)) * np.sqrt(
lshape * rshape)
else:
# otherwise, just use l2 \otimes l2
out = warn_default()
return out
from scipy.stats import chi import matplotlib.pyplot as plt fig, ax = plt.subplots(1, 1) # Calculate a few first moments: df = 78 mean, var, skew, kurt = chi.stats(df, moments='mvsk') # Display the probability density function (``pdf``): x = np.linspace(chi.ppf(0.01, df), chi.ppf(0.99, df), 100) ax.plot(x, chi.pdf(x, df), 'r-', lw=5, alpha=0.6, label='chi pdf') # Alternatively, the distribution object can be called (as a function) # to fix the shape, location and scale parameters. This returns a "frozen" # RV object holding the given parameters fixed. # Freeze the distribution and display the frozen ``pdf``: rv = chi(df) ax.plot(x, rv.pdf(x), 'k-', lw=2, label='frozen pdf') # Check accuracy of ``cdf`` and ``ppf``: vals = chi.ppf([0.001, 0.5, 0.999], df) np.allclose([0.001, 0.5, 0.999], chi.cdf(vals, df)) # True # Generate random numbers:
