correlospinmatrix_detector – Device for measuring the covariance matrix from several inputs =========================================================================================== Description +++++++++++ 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 ++++++++++ ================ ========= ==================================================== 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 ++++++++ SpikeEvent See also ++++++++ :doc:`Device `, :doc:`Detector `