def compute(i, j):
if i == j:
return 1.0
else:
if tau is None:
tau_mat = spq.minimum(
*spq.meshgrid(auto_taus[i], auto_taus[j])) / 2.0
else:
tau_mat = sp.tile(tau, (trains[j].size, trains[i].size))
coincidence = sp.sum(
kernel((trains[i] - sp.atleast_2d(trains[j]).T) / tau_mat))
normalization = 1.0 / sp.sqrt(trains[i].size * trains[j].size)
return normalization * coincidence
def compute(i, j):
if i == j:
return 1.0
else:
if tau is None:
tau_mat = spq.minimum(*spq.meshgrid(
auto_taus[i], auto_taus[j])) / 2.0
else:
tau_mat = sp.tile(tau, (trains[j].size, trains[i].size))
coincidence = sp.sum(kernel(
(trains[i] - sp.atleast_2d(trains[j]).T) / tau_mat))
normalization = 1.0 / sp.sqrt(trains[i].size * trains[j].size)
return normalization * coincidence
def event_synchronization(
trains, tau=None,
kernel=sigproc.RectangularKernel(1.0, normalize=False), sort=True):
""" event_synchronization(trains, tau=None, kernel=signal_processing.RectangularKernel(1.0, normalize=False), sort=True)
Calculates the event synchronization.
Let :math:`d(x|y)` be the count of spikes in :math:`y` which occur shortly
before an event in :math:`x` with a time difference of less than
:math:`\\tau`. Moreover, let :math:`n_x` and :math:`n_y` be the number of
total spikes in the spike trains :math:`x` and :math:`y`. The event
synchrony is then defined as :math:`Q_T = \\frac{d(x|y)
+ d(y|x)}{\\sqrt{n_x n_y}}`.
The time maximum time lag :math:`\\tau` can be determined automatically for
each pair of spikes :math:`t^x_i` and :math:`t^y_j` by the formula
:math:`\\tau_{ij} = \\frac{1}{2} \\min\{t^x_{i+1} - t^x_i, t^x_i - t^x_{i-1},
t^y_{j+1} - t^y_j, t^y_j - t^y_{j-1}\}`
Further and more detailed information can be found in
*Quiroga, R. Q., Kreuz, T., & Grassberger, P. (2002). Event
synchronization: a simple and fast method to measure synchronicity and time
delay patterns. Physical Review E, 66(4), 041904.*
:param sequence trains: Sequence of :class:`neo.core.SpikeTrain` objects of
which the van Rossum distance will be calculated pairwise.
:param tau: The maximum time lag for two spikes to be considered coincident
or synchronous as time scalar. To have it determined automatically by
above formula set it to `None`.
:type tau: Quantity scalar
:param kernel: Kernel to use in the calculation of the distance.
:type kernel: :class:`.signal_processing.Kernel`
:param bool sort: Spike trains with sorted spike times are be needed for
the calculation. You can set `sort` to `False` if you know that your
spike trains are already sorted to decrease calculation time.
:returns: Matrix containing the event synchronization for all pairs of spike
trains.
:rtype: 2-D array
"""
trains = [st.view(type=pq.Quantity) for st in trains]
if sort:
trains = [sp.sort(st) for st in trains]
if tau is None:
inf_array = sp.array([sp.inf])
isis = [spq.concatenate(
(inf_array * st.units, sp.diff(st), inf_array * st.units))
for st in trains]
auto_taus = [spq.minimum(t[:-1], t[1:]) for t in isis]
def compute(i, j):
if i == j:
return 1.0
else:
if tau is None:
tau_mat = spq.minimum(*spq.meshgrid(
auto_taus[i], auto_taus[j])) / 2.0
else:
tau_mat = sp.tile(tau, (trains[j].size, trains[i].size))
coincidence = sp.sum(kernel(
(trains[i] - sp.atleast_2d(trains[j]).T) / tau_mat))
normalization = 1.0 / sp.sqrt(trains[i].size * trains[j].size)
return normalization * coincidence
return _create_matrix_from_indexed_function(
(len(trains), len(trains)), compute, kernel.is_symmetric())
def event_synchronization(trains,
tau=None,
kernel=sigproc.RectangularKernel(1.0,
normalize=False),
sort=True):
""" event_synchronization(trains, tau=None, kernel=signal_processing.RectangularKernel(1.0, normalize=False), sort=True)
Calculates the event synchronization.
Let :math:`d(x|y)` be the count of spikes in :math:`y` which occur shortly
before an event in :math:`x` with a time difference of less than
:math:`\\tau`. Moreover, let :math:`n_x` and :math:`n_y` be the number of
total spikes in the spike trains :math:`x` and :math:`y`. The event
synchrony is then defined as :math:`Q_T = \\frac{d(x|y)
+ d(y|x)}{\\sqrt{n_x n_y}}`.
The time maximum time lag :math:`\\tau` can be determined automatically for
each pair of spikes :math:`t^x_i` and :math:`t^y_j` by the formula
:math:`\\tau_{ij} = \\frac{1}{2} \\min\{t^x_{i+1} - t^x_i, t^x_i - t^x_{i-1},
t^y_{j+1} - t^y_j, t^y_j - t^y_{j-1}\}`
Further and more detailed information can be found in
*Quiroga, R. Q., Kreuz, T., & Grassberger, P. (2002). Event
synchronization: a simple and fast method to measure synchronicity and time
delay patterns. Physical Review E, 66(4), 041904.*
:param sequence trains: Sequence of :class:`neo.core.SpikeTrain` objects of
which the van Rossum distance will be calculated pairwise.
:param tau: The maximum time lag for two spikes to be considered coincident
or synchronous as time scalar. To have it determined automatically by
above formula set it to `None`.
:type tau: Quantity scalar
:param kernel: Kernel to use in the calculation of the distance.
:type kernel: :class:`.signal_processing.Kernel`
:param bool sort: Spike trains with sorted spike times are be needed for
the calculation. You can set `sort` to `False` if you know that your
spike trains are already sorted to decrease calculation time.
:returns: Matrix containing the event synchronization for all pairs of spike
trains.
:rtype: 2-D array
"""
trains = [st.view(type=pq.Quantity) for st in trains]
if sort:
trains = [sp.sort(st) for st in trains]
if tau is None:
inf_array = sp.array([sp.inf])
isis = [
spq.concatenate(
(inf_array * st.units, sp.diff(st), inf_array * st.units))
for st in trains
]
auto_taus = [spq.minimum(t[:-1], t[1:]) for t in isis]
def compute(i, j):
if i == j:
return 1.0
else:
if tau is None:
tau_mat = spq.minimum(
*spq.meshgrid(auto_taus[i], auto_taus[j])) / 2.0
else:
tau_mat = sp.tile(tau, (trains[j].size, trains[i].size))
coincidence = sp.sum(
kernel((trains[i] - sp.atleast_2d(trains[j]).T) / tau_mat))
normalization = 1.0 / sp.sqrt(trains[i].size * trains[j].size)
return normalization * coincidence
return _create_matrix_from_indexed_function((len(trains), len(trains)),
compute, kernel.is_symmetric())
