def __init__(self,
alpha_0=None,
beta_0=None,
alphas_0=None,
betas_0=None,
r_support=None,
r_probs=None,
r_discrete_distn=None,
r=None,
ps=None):
assert (r_discrete_distn is not None) ^ (r_support is not None
and r_probs is not None)
if r_discrete_distn is not None:
r_support, = np.where(r_discrete_distn)
r_probs = r_discrete_distn[r_support]
r_support += 1
self.r_support = np.asarray(r_support)
self.rho_0 = self.rho_mf = np.log(r_probs)
assert (alpha_0 is not None and beta_0 is not None) \
^ (alphas_0 is not None and betas_0 is not None)
alphas_0 = alphas_0 if alphas_0 is not None else [alpha_0
] * len(r_support)
betas_0 = betas_0 if betas_0 is not None else [beta_0] * len(r_support)
ps = ps if ps is not None else [None] * len(r_support)
self._fixedr_distns = \
[self._fixedr_class(r=r,p=p,alpha_0=alpha_0,beta_0=beta_0)
for r,p,alpha_0,beta_0 in zip(r_support,ps,alphas_0,betas_0)]
# for init
self.ridx = sample_discrete(r_probs)
self.r = r_support[self.ridx]
def downsample_data_slow(X, n):
"""
Downsample each row of X such that it sums to n by randomly removing entries
"""
from pybasicbayes.util.stats import sample_discrete
assert X.ndim == 2
Xsub = X.copy()
for i in range(Xsub.shape[0]):
Mi = int(Xsub[i].sum())
assert Mi >= n
# if Mi > 1e8: print "Warning: M is really large!"
p = Xsub[i] / float(Mi)
# Random remove one of the entries to remove
for m in range(Mi-n):
k = sample_discrete(p)
assert Xsub[i,k] > 0
Xsub[i,k] -= 1
p = Xsub[i] / float(Xsub[i].sum())
assert Xsub[i].sum() == n
return Xsub
def resample(self,data=[]):
alpha_n, betas_n, posterior_discrete = self._posterior_hypparams(
*self._get_statistics(data))
r_idx = sample_discrete(posterior_discrete)
self.r = self.r_support[r_idx]
self.p = np.random.beta(alpha_n, betas_n[r_idx])
def downsample_data_slow(X, n):
"""
Downsample each row of X such that it sums to n by randomly removing entries
"""
from pybasicbayes.util.stats import sample_discrete
assert X.ndim == 2
Xsub = X.copy()
for i in xrange(Xsub.shape[0]):
Mi = int(Xsub[i].sum())
assert Mi >= n
# if Mi > 1e8: print "Warning: M is really large!"
p = Xsub[i] / float(Mi)
# Random remove one of the entries to remove
for m in xrange(Mi-n):
k = sample_discrete(p)
assert Xsub[i,k] > 0
Xsub[i,k] -= 1
p = Xsub[i] / float(Xsub[i].sum())
assert Xsub[i].sum() == n
return Xsub
def resample(self,data=[]):
alpha_n, betas_n, posterior_discrete = self._posterior_hypparams(
*self._get_statistics(data))
r_idx = sample_discrete(posterior_discrete)
self.r = self.r_support[r_idx]
self.p = np.random.beta(alpha_n, betas_n[r_idx])
def _generate(self, N):
# run a CRP forwards
alpha_0 = self.alpha_0
self.z = np.zeros(N, dtype=np.int32)
for n in range(N):
self.z[n] = sample_discrete(
np.concatenate((np.bincount(self.z[:n]), (alpha_0, ))))
def generate(self,
T=100,
keep=True,
init_data=None,
covariates=None,
with_noise=True):
from pybasicbayes.util.stats import sample_discrete
# Generate from the prior and raise exception if unstable
K, n = self.num_states, self.D
# Prepare the covariates
if covariates is None:
covariates = np.zeros((T, 0))
else:
assert covariates.shape[0] == T
# Initialize discrete state sequence
pi_0 = self.init_state_distn.pi_0
dss = np.empty(T, dtype=np.int32)
dss[0] = sample_discrete(pi_0.ravel())
data = np.empty((T, n), dtype='double')
if init_data is None:
data[0] = np.random.randn(n)
else:
data[0] = init_data
for t in range(1, T):
# Sample discrete state given previous continuous state and covariates
cov_t = np.column_stack((data[t - 1:t], covariates[t]))
A = self.trans_distn.get_trans_matrices(cov_t)[0]
dss[t] = sample_discrete(A[dss[t - 1], :])
# Sample continuous state given current discrete state
if with_noise:
data[t] = self.obs_distns[dss[t]].rvs(cov_t, return_xy=False)
else:
data[t] = self.obs_distns[dss[t]].predict(cov_t)
assert np.all(np.isfinite(
data[t])), "RARHMM appears to be unstable!"
# TODO:
# if keep:
# ...
return data, dss
def generate_states(self,
initial_condition=None,
with_noise=True,
stateseq=None):
"""
Jointly sample the discrete and continuous states
"""
from pybasicbayes.util.stats import sample_discrete
# Generate from the prior and raise exception if unstable
T, K, n = self.T, self.num_states, self.D_latent
# Initialize discrete state sequence
dss = -1 * np.ones(T, dtype=np.int32) if stateseq is None else stateseq
gss = np.empty((T, n), dtype='double')
if initial_condition is None:
init_state_distn = np.ones(self.num_states) / float(
self.num_states)
dss[0] = sample_discrete(init_state_distn.ravel())
gss[0] = self.init_dynamics_distns[dss[0]].rvs()
else:
dss[0] = initial_condition[0]
gss[0] = initial_condition[1]
for t in range(1, T):
# Sample discrete state given previous continuous state
A = self.trans_distn.get_trans_matrices(gss[t - 1:t])[0]
if with_noise:
# Sample discrete state from recurrent transition matrix
if dss[t] == -1:
dss[t] = sample_discrete(A[dss[t - 1], :])
# Sample continuous state given current discrete state
gss[t] = self.dynamics_distns[dss[t-1]].\
rvs(x=np.hstack((gss[t-1][None,:], self.inputs[t-1][None,:])),
return_xy=False)
else:
# Pick the most likely next discrete state and continuous state
if dss[t] == -1:
dss[t] = np.argmax(A[dss[t - 1], :])
gss[t] = self.dynamics_distns[dss[t-1]]. \
predict(np.hstack((gss[t-1][None,:], self.inputs[t-1][None,:])))
assert np.all(np.isfinite(gss[t])), "SLDS appears to be unstable!"
self.stateseq = dss
self.gaussian_states = gss
def energy(self,data):
# TODO TODO this function is horrible
assert data.ndim == 1
if np.isnan(data).any():
return 0.
from .util.stats import sample_discrete
likes = np.array([c.log_likelihood(data) for c in self.components]).reshape((-1,))
likes += np.log(self.weights.weights)
label = sample_discrete(np.exp(likes - likes.max()))
return self.components[label].energy(data)
def energy(self,data):
# TODO TODO this function is horrible
assert data.ndim == 1
if np.isnan(data).any():
return 0.
from .util.stats import sample_discrete
likes = np.array([c.log_likelihood(data) for c in self.components]).reshape((-1,))
likes += np.log(self.weights.weights)
label = sample_discrete(np.exp(likes - likes.max()))
return self.components[label].energy(data)
def sample(self, z, x, i, n):
""" Sample the next state given the previous time index
:param z: TxNxD buffer of particle states
:param x: NxD output buffer for observations
:param i: Time index to sample
:param n: Particle index to sample
"""
psi = np.dot(self.C, z[i, n, :]) + self.mu
pi = psi_to_pi(psi)
from pybasicbayes.util.stats import sample_discrete
s = sample_discrete(pi)
x[i, :] = 0
x[i, s] = 1
def generate_states(self, initial_condition=None, with_noise=True, stateseq=None):
"""
Generate discrete and continuous states. Note that the handling of 'with_noise'
differs slightly from pySLDS implementation. Rather than selecting the most
likely discrete state, we randomly sample the discrete statse.
"""
if stateseq is None:
As = self.trans_matrix
self.stateseq = -1 * np.ones(self.T, dtype=np.int32)
self.stateseq[0] = np.random.choice(self.num_states)
for t in range(1, self.T):
self.stateseq[t] = sample_discrete(As[t-1, self.stateseq[t-1], :].ravel())
else:
assert stateseq.shape == (self.T,)
self.stateseq = stateseq.astype(np.int32)
def sample(self, z, x, i,n):
""" Sample the next state given the previous time index
:param z: TxNxD buffer of particle states
:param x: NxD output buffer for observations
:param i: Time index to sample
:param n: Particle index to sample
"""
psi = np.dot(self.C, z[i,n,:]) + self.mu
pi = psi_to_pi(psi)
from pybasicbayes.util.stats import sample_discrete
s = sample_discrete(pi)
x[i,:] = 0
x[i,s] = 1
def rvs(self,customer_counts):
# could replace this with one of the faster C versions I have lying
# around, but at least the Python version is clearer
assert isinstance(customer_counts,list) or isinstance(customer_counts,int)
if isinstance(customer_counts,int):
customer_counts = [customer_counts]
restaurants = []
for num in customer_counts:
# a CRP with num customers
tables = []
for c in range(num):
newidx = sample_discrete(np.array(tables + [self.concentration]))
if newidx == len(tables):
tables += [1]
else:
tables[newidx] += 1
restaurants.append(tables)
return restaurants if len(restaurants) > 1 else restaurants[0]
def rvs(self,customer_counts):
# could replace this with one of the faster C versions I have lying
# around, but at least the Python version is clearer
assert isinstance(customer_counts,list) or isinstance(customer_counts,int)
if isinstance(customer_counts,int):
customer_counts = [customer_counts]
restaurants = []
for num in customer_counts:
# a CRP with num customers
tables = []
for c in range(num):
newidx = sample_discrete(np.array(tables + [self.concentration]))
if newidx == len(tables):
tables += [1]
else:
tables[newidx] += 1
restaurants.append(tables)
return restaurants if len(restaurants) > 1 else restaurants[0]
def __init__(self,alpha_0=None,beta_0=None,alphas_0=None,betas_0=None,
r_support=None,r_probs=None,r_discrete_distn=None,
r=None,ps=None):
assert (r_discrete_distn is not None) ^ (r_support is not None and r_probs is not None)
if r_discrete_distn is not None:
r_support, = np.where(r_discrete_distn)
r_probs = r_discrete_distn[r_support]
r_support += 1
self.r_support = np.asarray(r_support)
self.rho_0 = self.rho_mf = np.log(r_probs)
assert (alpha_0 is not None and beta_0 is not None) \
^ (alphas_0 is not None and betas_0 is not None)
alphas_0 = alphas_0 if alphas_0 is not None else [alpha_0]*len(r_support)
betas_0 = betas_0 if betas_0 is not None else [beta_0]*len(r_support)
ps = ps if ps is not None else [None]*len(r_support)
self._fixedr_distns = \
[self._fixedr_class(r=r,p=p,alpha_0=alpha_0,beta_0=beta_0)
for r,p,alpha_0,beta_0 in zip(r_support,ps,alphas_0,betas_0)]
# for init
self.ridx = sample_discrete(r_probs)
self.r = r_support[self.ridx]
def resample(self,data=[]):
n, alpha_n, posterior_discrete, r_support = self._posterior_hypparams(
*self._get_statistics(data)) # NOTE: pass out r_support b/c feasible subset
self.r = r_support[sample_discrete(posterior_discrete)]
self.p = np.random.beta(alpha_n - n*self.r, self.beta_0 + n*self.r)
def _resample_r(self,data):
self.ridx = sample_discrete(
self._posterior_hypparams(self._get_statistics(data)))
self.r = self.r_support[self.ridx]
return self
def _resample_r_from_mf(self):
lognorm = logsumexp(self.rho_mf)
self.ridx = sample_discrete(np.exp(self.rho_mf - lognorm))
self.r = self.r_support[self.ridx]
def rvs(self,size=None):
return sample_discrete(self.weights,size)
def rvs(self, size=None):
return sample_discrete(self.weights, size)
def resample_Z_python(self):
from pybasicbayes.util.stats import sample_discrete
# TODO: Call cython function to resample parents
S, C, Z, dt_max = self.S, self.C, self.Z, self.dt_max
lambda0 = self.model.bias_model.lambda0
W = self.model.weight_model.W
impulse = self.model.impulse_model.impulse
# Also compute number of parents assigned to background rate and
# to specific connections
self.bkgd_ss = np.zeros(self.K)
self.weight_ss = np.zeros((self.K, self.K))
self.imp_ss = np.zeros((self.K, self.K))
# Resample parents
for n in range(self.N):
if n == 0:
Z[n] = -1
self.bkgd_ss[C[n]] += 1
continue
# Compute the probability of each parent spike
p_par = np.zeros(n)
denom = 0
# First parent is just the background rate of this process
p_bkgd = lambda0[C[n]]
denom += p_bkgd
# Iterate backward from the most recent to compute probabilities of each parent spike
for par in range(n - 1, -1, -1):
dt = S[n] - S[par]
# Since the spikes are sorted, we can stop if we reach a potential
# parent that occurred greater than dt_max in the past
if dt > dt_max:
p_par[par] = 0
break
p_par[par] = W[C[par], C[n]] * impulse(dt, C[par], C[n])
denom += p_par[par]
# Now sample forward, starting from the minimum viable parent
min_par = par
p_par = np.concatenate([[p_bkgd], p_par[min_par:n]])
# Sample from the discrete distribution p_par
i_par = sample_discrete(p_par)
if i_par == 0:
# Sampled the background rate
Z[n] = -1
self.bkgd_ss[C[n]] += 1
else:
# Sampled one of the preceding spikes
Z[n] = (i_par - 1) + min_par
Cp = C[Z[n]]
dt = S[n] - S[Z[n]]
self.weight_ss[Cp, C[n]] += 1
self.imp_ss[Cp, C[n]] += np.log(dt) - np.log(dt_max - dt)
def resample_Z_python(self):
from pybasicbayes.util.stats import sample_discrete
# TODO: Call cython function to resample parents
S, C, Z, dt_max = self.S, self.C, self.Z, self.dt_max
lambda0 = self.model.bias_model.lambda0
W = self.model.weight_model.W_effective
impulse = self.model.impulse_model.impulse
translate_dt = self.model.impulse_model.translate_dt
# Also compute number of parents assigned to background rate and
# to specific connections
self.bkgd_ss = np.zeros(self.K)
self.weight_ss = np.zeros((self.K, self.K))
self.imp_ss = np.zeros((3, self.K, self.K))
# Resample parents
for n in range(self.N):
if n == 0:
Z[n] = -1
self.bkgd_ss[C[n]] += 1
continue
# Compute the probability of each parent spike
p_par = np.zeros(n)
denom = 0
# First parent is just the background rate of this process
p_bkgd = lambda0[C[n]]
denom += p_bkgd
# Iterate backward from the most recent to compute probabilities of each parent spike
for par in range(n - 1, -1, -1):
dt = S[n] - S[par]
if dt < 1e-8:
continue
if dt > dt_max - 1e-8:
break
p_par[par] = W[C[par], C[n]] * impulse(dt, C[par], C[n])
denom += p_par[par]
# Now sample forward, starting from the minimum viable parent
min_par = par
p_par = np.concatenate([[p_bkgd], p_par[min_par:n]])
# Sample from the discrete distribution p_par
i_par = sample_discrete(p_par)
if i_par == 0:
# Sampled the background rate
Z[n] = -1
self.bkgd_ss[C[n]] += 1
else:
# Sampled one of the preceding spikes
Z[n] = (i_par - 1) + min_par
Cp = C[Z[n]]
# dt = S[n] - S[Z[n]]
dt = translate_dt(S[n] - S[Z[n]])
self.weight_ss[Cp, C[n]] += 1
self.imp_ss[0, Cp, C[n]] += 1
self.imp_ss[1, Cp, C[n]] += np.log(dt) - np.log(dt_max - dt)
self.Z = Z
# sum of squares of impulse responses
mu = np.divide(self.imp_ss[1], self.imp_ss[0])
for n in range(self.N):
par = Z[n]
if par > -1:
# dt = S[n] - S[par]
dt = translate_dt(S[n] - S[par])
sdt = np.log(dt) - np.log(dt_max - dt)
self.imp_ss[2, C[par], C[n]] += (sdt - mu[C[par], C[n]])**2
def resample_Z_python(self):
from pybasicbayes.util.stats import sample_discrete
# TODO: Call cython function to resample parents
S, C, Z, dt_max = self.S, self.C, self.Z, self.dt_max
lambda0 = self.model.bias_model.lambda0
W = self.model.weight_model.W
impulse = self.model.impulse_model.impulse
# Also compute number of parents assigned to background rate and
# to specific connections
self.bkgd_ss = np.zeros(self.K)
self.weight_ss = np.zeros((self.K, self.K))
self.imp_ss = np.zeros((self.K, self.K))
# Resample parents
for n in range(self.N):
if n == 0:
Z[n] = -1
self.bkgd_ss[C[n]] += 1
continue
# Compute the probability of each parent spike
p_par = np.zeros(n)
denom = 0
# First parent is just the background rate of this process
p_bkgd = lambda0[C[n]]
denom += p_bkgd
# Iterate backward from the most recent to compute probabilities of each parent spike
for par in range(n-1, -1, -1):
dt = S[n] - S[par]
# Since the spikes are sorted, we can stop if we reach a potential
# parent that occurred greater than dt_max in the past
if dt > dt_max:
p_par[par] = 0
break
p_par[par] = W[C[par], C[n]] * impulse(dt, C[par], C[n])
denom += p_par[par]
# Now sample forward, starting from the minimum viable parent
min_par = par
p_par = np.concatenate([[p_bkgd], p_par[min_par:n]])
# Sample from the discrete distribution p_par
i_par = sample_discrete(p_par)
if i_par == 0:
# Sampled the background rate
Z[n] = -1
self.bkgd_ss[C[n]] += 1
else:
# Sampled one of the preceding spikes
Z[n] = (i_par - 1) + min_par
Cp = C[Z[n]]
dt = S[n] - S[Z[n]]
self.weight_ss[Cp, C[n]] += 1
self.imp_ss[Cp, C[n]] += np.log(dt) - np.log(dt_max - dt)
def _generate(self,N):
# run a CRP forwards
alpha_0 = self.alpha_0
self.z = np.zeros(N,dtype=np.int32)
for n in range(N):
self.z[n] = sample_discrete(np.concatenate((np.bincount(self.z[:n]),(alpha_0,))))
def _resample_r_from_mf(self):
lognorm = logsumexp(self.rho_mf)
self.ridx = sample_discrete(np.exp(self.rho_mf - lognorm))
self.r = self.r_support[self.ridx]
def resample(self,data=[]):
n, alpha_n, posterior_discrete, r_support = self._posterior_hypparams(
*self._get_statistics(data)) # NOTE: pass out r_support b/c feasible subset
self.r = r_support[sample_discrete(posterior_discrete)]
self.p = np.random.beta(alpha_n - n*self.r, self.beta_0 + n*self.r)
def _resample_r(self,data):
self.ridx = sample_discrete(
self._posterior_hypparams(self._get_statistics(data)))
self.r = self.r_support[self.ridx]
return self
