correlospinmatrix_detector – Device for measuring the covariance matrix from several inputs
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Description
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The ``correlospinmatrix_detector`` is a device that receives input from several
binary neuron sources and calculates the raw auto and cross correlation binned
to bins of duration delta_tau, which defaults to the simulation resolution.
The result can be obtained from the node's status dictionary under the key
``count_covariance`` in the format of a tensor of rank 3 of size
``N_channels`` x ``N_channels``, with each entry :math:`C_{ij}` being a vector
of size :math:`2\cdot\tau_{max}/\delta_{\tau} + 1` containing the histogram for
the different time lags.
The bins are centered around the time difference they represent, and are
left-closed and right-open in the lower triangular part of the matrix. On the
diagonal and in the upper triangular part the intervals are left-open and
right-closed. This ensures proper counting of events at the border of bins.
The ``correlospinmatrix_detector`` has a variable number of inputs which can be
set via SetStatus under the key N_channels. All incoming connections to a
specified receptor will be pooled.
Setting either N_channels, Tstart, Tstop, tau_max or delta_tau clears
count_covariance.
Correlospinmatrix detectors ignore any connection delays.
See :doc:`../auto_examples/correlospinmatrix_detector_two_neuron` for
a script reproducing a setting studied in Fig 1 of Grinzburg &
Sompolinsky (1994) PRE 50(4) p. 3171.
Parameters
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================ ========= ====================================================
Tstart real Time when to start counting events. This time should
be set to at least start + tau_max in order to avoid
edge effects of the correlation counts.
Tstop real Time when to stop counting events. This time should
be set to at most Tsim - tau_max, where Tsim is the
duration of simulation, in order to avoid edge
effects of the correlation counts.
delta_tau ms Bin width. This has to be an odd multiple of
the resolution, to allow the symmetry between
positive and negative time-lags. Defaults to the
simulation resolution.
tau_max ms One-sided width. In the lower triagnular part
events with differences in [0, tau_max+delta_tau/2)
are counted. On the diagonal and in the upper
triangular part events with differences in
(0, tau_max+delta_tau/2]. Defaults to 10 times the
value of delta_tau.
N_channels integer The number of pools. This defines the range of
receptor_type. Default is 1.
Setting N_channels clears count_covariance,
covariance and n_events.
covariance 3D matrix of read-only -raw, weighted, auto/cross
matrix of correlation
integers
count_covariance 3D matrix of read-only -raw, auto/cross correlation
matrix of counts
integers
================ ========= ====================================================
Receives
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SpikeEvent
See also
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:doc:`Device `, :doc:`Detector `
Examples using this model
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.. listexamples:: correlospinmatrix_detector