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correlospinmatrix_detector – Device for measuring the covariance matrix from several inputs


The correlospinmatrix_detector is a recording device. It is used to record correlations from binary neurons from several binary sources and calculates the raw auto and cross correlation binned to bins of duration delta_tau. The result can be obtained via GetStatus under the key /count_covariance. The result is a tensor of rank 3 of size N_channels x N_channels, with each entry \(C_{ij}\) being a vector of size \(2*\tau_{max}/\delta_{\tau} + 1\) 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.


This recorder does not record to file, screen or memory in the usual sense. The result must be obtained by a call to GetStatus. Setting either N_channels, Tstart, Tstop, tau_max or delta_tau clears count_covariance.

Correlospinmatrix detectors IGNORE any connection delays.

Correlospinmatrix detector breaks with the persistence scheme as follows: the internal buffers for storing spikes are part of State_, but are initialized by init_buffers_().

See pynest/examples/correlospinmatrix_detector_two_neuron.py for a script reproducing a setting studied in Fig 1 of Grinzburg & Sompolinsky (1994) PRE 50(4) p. 3171.




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.



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.



Bin width. This has to be an odd multiple of the resolution, to allow the symmetry between positive and negative time-lags.



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].



The number of pools. This defines the range of receptor_type. Default is 1. Setting N_channels clears count_covariance, covariance and n_events.


3D matrix of integers

matrix of read-only -raw, weighted, auto/cross correlation


3D matrix of integers

matrix of read-only -raw, auto/cross correlation counts



See also

Device, Detector