def logp(self, X):
v = self.v
p = self.p
Z = self.Z
inv_S = self.inv_S
result = -Z + log(det(X)) * (v - p - 1) / 2. - trace(inv_S.dot(X)) / 2.
return ifelse(gt(v, p-1), result, self.invalid)
def logp(self, X):
v = self.v
p = self.p
S = self.S
Z = self.Z
result = -Z + log(det(X)) * -(v + p + 1.) / 2. - trace(S.dot(matrix_inverse(X))) / 2.
return ifelse(gt(v, p-1), result, self.invalid)
def __init__(self, mu, sigma, random_state=None):
super(MultivariateNormal, self).__init__(mu=mu,
sigma=sigma,
random_state=random_state,
optimizer=None)
# XXX: The SDP-ness of sigma should be check upon changes
# ndim
self.ndim_ = self.mu.shape[0]
self.make_(self.ndim_, "ndim_func_", args=[])
# pdf
L = linalg.cholesky(self.sigma)
sigma_det = linalg.det(self.sigma) # XXX: compute from L instead
sigma_inv = linalg.matrix_inverse(self.sigma) # XXX: idem
self.pdf_ = (
(1. / T.sqrt((2. * np.pi) ** self.ndim_ * T.abs_(sigma_det))) *
T.exp(-0.5 * T.sum(T.mul(T.dot(self.X - self.mu,
sigma_inv),
self.X - self.mu),
axis=1))).ravel()
self.make_(self.pdf_, "pdf")
# -log pdf
self.nnlf_ = -T.log(self.pdf_) # XXX: for sure this can be better
self.make_(self.nnlf_, "nnlf")
# self.rvs_
self.make_(T.dot(L, self.X.T).T + self.mu, "rvs_func_")
def __init__(self, mu, sigma, random_state=None):
super(MultivariateNormal, self).__init__(mu=mu, sigma=sigma)
# XXX: The SDP-ness of sigma should be check upon changes
# ndim
self.ndim_ = self.mu.shape[0]
self.make_(self.ndim_, "ndim_func_", args=[])
# pdf
L = linalg.cholesky(self.sigma)
sigma_det = linalg.det(self.sigma) # XXX: compute from L instead
sigma_inv = linalg.matrix_inverse(self.sigma) # XXX: idem
self.pdf_ = ((1. / T.sqrt(
(2. * np.pi)**self.ndim_ * T.abs_(sigma_det))) *
T.exp(-0.5 * T.sum(T.mul(
T.dot(self.X - self.mu, sigma_inv), self.X - self.mu),
axis=1))).ravel()
self.make_(self.pdf_, "pdf")
# -log pdf
self.nll_ = -T.log(self.pdf_) # XXX: for sure this can be better
self.make_(self.nll_, "nll")
# self.rvs_
self.make_(T.dot(L, self.X.T).T + self.mu, "rvs_func_")
def logp(self, value):
mu = self.mu
tau = self.tau
delta = value - mu
k = tau.shape[0]
return 1/2. * (-k * log(2*pi) + log(det(tau)) - dot(delta.T, dot(tau, delta)))
def logp(X):
IVI = det(V)
return bound(
((n - p - 1) * log(IVI) - trace(matrix_inverse(V).dot(X)) -
n * p * log(
2) - n * log(IVI) - 2 * multigammaln(p, n / 2)) / 2,
all(n > p - 1))
def logp(X):
IVI = det(V)
return bound(
((n - p - 1) * log(IVI) - trace(solve(V, X)) -
n * p * log(
2) - n * log(IVI) - 2 * multigammaln(p, n / 2)) / 2,
n > p - 1)
def step(visible, filtered_hidden_mean_m1, filtered_hidden_cov_m1):
A, B = transition, emission # (h, h), (h, v)
# Shortcuts for the filtered mean and covariance from the previous
# time step.
f_m1 = filtered_hidden_mean_m1 # (n, h)
F_m1 = filtered_hidden_cov_m1 # (n, h, h)
# Calculate mean of joint.
hidden_mean = T.dot(f_m1, A) + hnm # (n, h)
visible_mean = T.dot(hidden_mean, B) + vnm # (n, v)
# Calculate covariance of joint.
hidden_cov = stacked_dot(A.T, stacked_dot(F_m1, A)) # (n, h, h)
hidden_cov += hnc
visible_cov = stacked_dot( # (n, v, v)
B.T, stacked_dot(hidden_cov, B))
visible_cov += vnc
visible_hidden_cov = stacked_dot(hidden_cov, B) # (n, h, v)
visible_error = visible - visible_mean # (n, v)
inv_visible_cov, _ = theano.map(lambda x: matrix_inverse(x),
visible_cov) # (n, v, v)
# I don't know a better name for this monster.
visible_hidden_cov_T = visible_hidden_cov.dimshuffle(0, 2,
1) # (n, v, h)
D = stacked_dot(inv_visible_cov, visible_hidden_cov_T)
f = (
D * visible_error.dimshuffle(0, 1, 'x') # (n, h)
).sum(axis=1)
f += hidden_mean
F = hidden_cov
F -= stacked_dot(visible_hidden_cov, D)
log_l = (
inv_visible_cov * # (n,)
visible_error.dimshuffle(0, 1, 'x') *
visible_error.dimshuffle(0, 'x', 1)).sum(axis=(1, 2))
log_l *= -.5
dets, _ = theano.map(lambda x: det(x), visible_cov)
log_l -= 0.5 * T.log(dets)
log_l -= np.log(2 * np.pi)
return f, F, log_l
def __init__(self, v, S, *args, **kwargs):
super(Wishart, self).__init__(*args, **kwargs)
self.v = v
self.S = S
self.p = p = S.shape[0]
self.inv_S = matrix_inverse(S)
'TODO: We should pre-compute the following if the parameters are fixed'
self.invalid = theano.tensor.fill(S, nan) # Invalid result, if v<p
self.Z = log(2.)*(v * p / 2.) + multigammaln(p, v / 2.) - log(det(S)) * v / 2.,
self.mean = ifelse(gt(v, p-1), S / ( v - p - 1), self.invalid)
def s_nll(self):
""" Marginal negative log likelihood of model
:note: See RW.pdf page 37, Eq. 2.30.
"""
K, y, var_y, N = self.kyn()
rK = psd(K + var_y * tensor.eye(N))
nll = (0.5 * dots(y, matrix_inverse(rK), y) +
0.5 * tensor.log(det(rK)) + N / 2.0 * tensor.log(2 * numpy.pi))
if nll.dtype != self.dtype:
raise TypeError('nll dtype', nll.dtype)
return nll
def step(visible, filtered_hidden_mean_m1, filtered_hidden_cov_m1):
A, B = transition, emission # (h, h), (h, v)
# Shortcuts for the filtered mean and covariance from the previous
# time step.
f_m1 = filtered_hidden_mean_m1 # (n, h)
F_m1 = filtered_hidden_cov_m1 # (n, h, h)
# Calculate mean of joint.
hidden_mean = T.dot(f_m1, A) + hnm # (n, h)
visible_mean = T.dot(hidden_mean, B) + vnm # (n, v)
# Calculate covariance of joint.
hidden_cov = stacked_dot(
A.T, stacked_dot(F_m1, A)) # (n, h, h)
hidden_cov += hnc
visible_cov = stacked_dot( # (n, v, v)
B.T, stacked_dot(hidden_cov, B))
visible_cov += vnc
visible_hidden_cov = stacked_dot(hidden_cov, B) # (n, h, v)
visible_error = visible - visible_mean # (n, v)
inv_visible_cov, _ = theano.map(
lambda x: matrix_inverse(x), visible_cov) # (n, v, v)
# I don't know a better name for this monster.
visible_hidden_cov_T = visible_hidden_cov.dimshuffle(0, 2, 1) # (n, v, h)
D = stacked_dot(inv_visible_cov, visible_hidden_cov_T)
f = (D * visible_error.dimshuffle(0, 1, 'x') # (n, h)
).sum(axis=1)
f += hidden_mean
F = hidden_cov
F -= stacked_dot(visible_hidden_cov, D)
log_l = (inv_visible_cov * # (n,)
visible_error.dimshuffle(0, 1, 'x') *
visible_error.dimshuffle(0,'x', 1)).sum(axis=(1, 2))
log_l *= -.5
dets, _ = theano.map(lambda x: det(x), visible_cov)
log_l -= 0.5 * T.log(dets)
log_l -= np.log(2 * np.pi)
return f, F, log_l
def s_nll(self):
""" Marginal negative log likelihood of model
:note: See RW.pdf page 37, Eq. 2.30.
"""
K, y, var_y, N = self.kyn()
rK = psd(K + var_y * tensor.eye(N))
nll = (0.5 * dots(y, matrix_inverse(rK), y)
+ 0.5 * tensor.log(det(rK))
+ N / 2.0 * tensor.log(2 * numpy.pi))
if nll.dtype != self.dtype:
raise TypeError('nll dtype', nll.dtype)
return nll
def log_partf(b, s, C, v, logdet=None):
D = b.size
# multivariate log-gamma function
g = tt.sum(tt.gammaln((v + 1. - tt.arange(1, D + 1)) /
2.)) + D * (D - 1) / 4. * np.log(np.pi)
# log-partition function
if logdet is None:
return -v / 2. * tt.log(tl.det(C - tt.dot(b, b.T) / (4 * s))) \
+ v * np.log(2.) + g - D / 2. * tt.log(s)
else:
return -v / 2. * logdet + v * np.log(2.) + g - D / 2. * tt.log(s)
def logp(self, X):
n = self.n
p = self.p
V = self.V
IVI = det(V)
return bound(
((n - p - 1) * log(IVI) - trace(matrix_inverse(V).dot(X)) -
n * p * log(
2) - n * log(IVI) - 2 * multigammaln(p, n / 2)) / 2,
n > (p - 1))
def s_nll(K, y, var_y, prior_var):
"""
Marginal negative log likelihood of model
K - gram matrix (matrix-like)
y - the training targets (vector-like)
var_y - the variance of uncertainty about y (vector-like)
:note: See RW.pdf page 37, Eq. 2.30.
"""
n = y.shape[0]
rK = psd(prior_var * K + var_y * TT.eye(n))
fit = .5 * dots(y, matrix_inverse(rK), y)
complexity = 0.5 * TT.log(det(rK))
normalization = n / 2.0 * TT.log(2 * np.pi)
nll = fit + complexity + normalization
return nll
def normal(X, m, C):
"""
Evaluates the density of a normal distribution.
@type X: C{TensorVariable}
@param X: matrix storing data points column-wise
@type m: C{ndarray}/C{TensorVariable}
@param m: column vector representing the mean of the Gaussian
@type C: C{ndarray}/C{TensorVariable}
@param C: covariance matrix
@rtype: C{TensorVariable}
@return: density of a Gaussian distribution evaluated at C{X}
"""
Z = X - m
return tt.exp(-tt.sum(Z * tt.dot(tl.matrix_inverse(C), Z), 0) / 2. -
tt.log(tl.det(C)) / 2. - m.size / 2. * np.log(2. * np.pi))
def __init__(self, mu, sigma):
"""Constructor.
Parameters
----------
* `mu` [1d array]:
The means.
* `sigma` [2d array]:
The covariance matrix.
"""
super(MultivariateNormal, self).__init__(mu=mu, sigma=sigma)
# XXX: The SDP-ness of sigma should be check upon changes
# ndim
self.ndim_ = self.mu.shape[0]
self._make(self.ndim_, "ndim_func_", args=[])
# pdf
L = linalg.cholesky(self.sigma)
sigma_det = linalg.det(self.sigma) # XXX: compute from L instead
sigma_inv = linalg.matrix_inverse(self.sigma) # XXX: idem
self.pdf_ = (
(1. / T.sqrt((2. * np.pi) ** self.ndim_ * T.abs_(sigma_det))) *
T.exp(-0.5 * T.sum(T.mul(T.dot(self.X - self.mu,
sigma_inv),
self.X - self.mu),
axis=1))).ravel()
self._make(self.pdf_, "pdf")
# -log pdf
self.nll_ = -T.log(self.pdf_) # XXX: for sure this can be better
self._make(self.nll_, "nll")
# self.rvs_
self._make(T.dot(L, self.X.T).T + self.mu, "rvs_func_")
def logp(value):
delta = value - mu
k = tau.shape[0]
return 1/2. * (-k * log(2*pi) + log(det(tau)) - dot(delta.T, dot(tau, delta)))
def logp(value):
delta = value - mu
return 1 / 2. * (log(det(Tau)) - dot(delta.T, dot(Tau, delta)))
def logp(value):
delta = value - mu
k = tau.shape[0]
return 1/2. * (-k * log(2*pi) + log(det(tau)) - dot(delta.T, dot(tau, delta)))
def logp(X):
IVI = det(V)
return bound(
((n - p - 1) * log(IVI) - trace(solve(V, X)) - n * p * log(2) -
n * log(IVI) - 2 * multigammaln(p, n / 2)) / 2, n > p - 1)
def log_detIM( M = Th.dmatrix('M') , **result):
return Th.log( det( Th.identity_like(M)-(M+M.T)/2 ) )
def logp(value):
delta = value - mu
return 1 / 2. * (log(det(Tau)) - dot(delta.T, dot(Tau, delta)))