def __init__(self, B):
"""
Create a 1D Gaussian output model.
Parameters
----------
B : ndarray((N,M),dtype=float)
output probability matrix using N hidden states and M observable symbols.
This matrix needs to be row-stochastic.
Examples
--------
Create an observation model.
>>> import numpy as np
>>> B = np.array([[0.5,0.5],[0.1,0.9]])
>>> output_model = DiscreteOutputModel(B)
"""
self._output_probabilities = np.array(B, dtype=config.dtype)
nstates,self._nsymbols = self._output_probabilities.shape[0],self._output_probabilities.shape[1]
# superclass constructor
OutputModel.__init__(self, nstates)
# test if row-stochastic
assert np.allclose(np.sum(self._output_probabilities, axis=1), np.ones(self.nstates)), 'B is not a stochastic matrix'
# set output matrix
self._output_probabilities = B
def __init__(self, B):
"""
Create a 1D Gaussian output model.
Parameters
----------
B : ndarray((N,M),dtype=float)
output probability matrix using N hidden states and M observable symbols.
This matrix needs to be row-stochastic.
Examples
--------
Create an observation model.
>>> import numpy as np
>>> B = np.array([[0.5,0.5],[0.1,0.9]])
>>> output_model = DiscreteOutputModel(B)
"""
self._output_probabilities = np.array(B, dtype=config.dtype)
nstates,self._nsymbols = self._output_probabilities.shape[0],self._output_probabilities.shape[1]
# superclass constructor
OutputModel.__init__(self, nstates)
# test if row-stochastic
assert np.allclose(np.sum(self._output_probabilities, axis=1), np.ones(self.nstates)), 'B is not a stochastic matrix'
# set output matrix
self._output_probabilities = B
def __init__(self, B, prior=None, ignore_outliers=False):
"""
Create a 1D Gaussian output model.
Parameters
----------
B : ndarray((N, M), dtype=float)
output probability matrix using N hidden states and M observable symbols.
This matrix needs to be row-stochastic.
prior : None or broadcastable to ndarray((N, M), dtype=float)
Prior for the initial distribution of the HMM.
Currently implements the Dirichlet prior that is conjugate to the
Dirichlet distribution of :math:`b_i`. :math:`b_i` is sampled from:
.. math:
b_i \sim \prod_j b_{ij}_i^{a_{ij} + n_{ij} - 1}
where :math:`n_{ij}` are the number of times symbol :math:`j` has
been observed when the hidden trajectory was in state :math:`i`
and :math:`a_{ij}` is the prior count.
The default prior=None corresponds to :math:`a_{ij} = 0`.
This option ensures coincidence between sample mean an MLE.
Examples
--------
Create an observation model.
>>> import numpy as np
>>> B = np.array([[0.5, 0.5], [0.1, 0.9]])
>>> output_model = DiscreteOutputModel(B)
"""
self._output_probabilities = np.array(B, dtype=config.dtype)
nstates, self._nsymbols = self._output_probabilities.shape[
0], self._output_probabilities.shape[1]
# superclass constructor
OutputModel.__init__(self, nstates, ignore_outliers=ignore_outliers)
# test if row-stochastic
assert np.allclose(self._output_probabilities.sum(axis=1),
np.ones(self.nstates)), 'B is no stochastic matrix'
# set prior matrix
if prior is None:
prior = np.zeros((nstates, self._nsymbols))
else:
prior = np.zeros(
(nstates,
self._nsymbols)) + prior # will fail if not broadcastable
self.prior = prior
def __init__(self, nstates, means=None, sigmas=None):
"""
Create a 1D Gaussian output model.
Parameters
----------
nstates : int
The number of output states.
means : array_like of shape (nstates,), optional, default=None
If specified, initialize the Gaussian means to these values.
sigmas : array_like of shape (nstates,), optional, default=None
If specified, initialize the Gaussian variances to these values.
Examples
--------
Create an observation model.
>>> output_model = GaussianOutputModel(nstates=3, means=[-1, 0, 1], sigmas=[0.5, 1, 2])
"""
OutputModel.__init__(self, nstates)
dtype = config.dtype # type for internal storage
if means is not None:
self._means = np.array(means, dtype=dtype)
if self._means.shape != (nstates, ):
raise Exception('means must have shape (%d,); instead got %s' %
(nstates, str(self._means.shape)))
else:
self._means = np.zeros([nstates], dtype=dtype)
if sigmas is not None:
self._sigmas = np.array(sigmas, dtype=dtype)
if self._sigmas.shape != (nstates, ):
raise Exception(
'sigmas must have shape (%d,); instead got %s' %
(nstates, str(self._sigmas.shape)))
else:
self._sigmas = np.zeros([nstates], dtype=dtype)
return
def __init__(self, B, prior=None, ignore_outliers=False):
"""
Create a 1D Gaussian output model.
Parameters
----------
B : ndarray((N, M), dtype=float)
output probability matrix using N hidden states and M observable symbols.
This matrix needs to be row-stochastic.
prior : None or broadcastable to ndarray((N, M), dtype=float)
Prior for the initial distribution of the HMM.
Currently implements the Dirichlet prior that is conjugate to the
Dirichlet distribution of :math:`b_i`. :math:`b_i` is sampled from:
.. math:
b_i \sim \prod_j b_{ij}_i^{a_{ij} + n_{ij} - 1}
where :math:`n_{ij}` are the number of times symbol :math:`j` has
been observed when the hidden trajectory was in state :math:`i`
and :math:`a_{ij}` is the prior count.
The default prior=None corresponds to :math:`a_{ij} = 0`.
This option ensures coincidence between sample mean an MLE.
Examples
--------
Create an observation model.
>>> import numpy as np
>>> B = np.array([[0.5, 0.5], [0.1, 0.9]])
>>> output_model = DiscreteOutputModel(B)
"""
self._output_probabilities = np.array(B, dtype=config.dtype)
nstates, self._nsymbols = self._output_probabilities.shape[0], self._output_probabilities.shape[1]
# superclass constructor
OutputModel.__init__(self, nstates, ignore_outliers=ignore_outliers)
# test if row-stochastic
assert np.allclose(self._output_probabilities.sum(axis=1), np.ones(self.nstates)), 'B is no stochastic matrix'
# set prior matrix
if prior is None:
prior = np.zeros((nstates, self._nsymbols))
else:
prior = np.zeros((nstates, self._nsymbols)) + prior # will fail if not broadcastable
self.prior = prior
def __init__(self, nstates, means=None, sigmas=None, ignore_outliers=True):
"""
Create a 1D Gaussian output model.
Parameters
----------
nstates : int
The number of output states.
means : array_like of shape (nstates,), optional, default=None
If specified, initialize the Gaussian means to these values.
sigmas : array_like of shape (nstates,), optional, default=None
If specified, initialize the Gaussian variances to these values.
Examples
--------
Create an observation model.
>>> output_model = GaussianOutputModel(nstates=3, means=[-1, 0, 1], sigmas=[0.5, 1, 2])
"""
OutputModel.__init__(self, nstates, ignore_outliers=ignore_outliers)
dtype = config.dtype # type for internal storage
if means is not None:
self._means = np.array(means, dtype=dtype)
if self._means.shape != (nstates,):
raise Exception('means must have shape (%d,); instead got %s' % (nstates, str(self._means.shape)))
else:
self._means = np.zeros([nstates], dtype=dtype)
if sigmas is not None:
self._sigmas = np.array(sigmas, dtype=dtype)
if self._sigmas.shape != (nstates,):
raise Exception('sigmas must have shape (%d,); instead got %s' % (nstates, str(self._sigmas.shape)))
else:
self._sigmas = np.zeros([nstates], dtype=dtype)
return
