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CrossCorrelation

Namespace: CONNECTIVITYLIB  ·  Library: Connectivity Library

#include <connectivity/crosscorrelation.h>

class CONNECTIVITYLIB::CrossCorrelation

Computes the time-lagged cross-correlation between every channel pair via the inverse FFT of the DPSS-tapered cross-spectrum, and reduces it to the maximum absolute correlation over the lag axis.

Per-trial computations are dispatched through QtConcurrent::mapped and accumulated under a single QMutex. The estimator is broadband and does not reject zero-lag mixing, but - unlike Correlation - is sensitive to delayed coupling because the lag axis is searched.

Time-lagged cross-correlation estimator; broadband, sensitive to delayed coupling.

src/examples/ex_connectivity_metrics/main.cpp
Network crossCorrelation = CrossCorrelation::calculate(settings);
const double xcor01 = edgeWeight(crossCorrelation, 0, 1);

Inheritance​

Public Methods​

CrossCorrelation()​

Constructs a CrossCorrelation object.

Static Methods​

calculate(connectivitySettings)​

Calculates the cross correlation between the rows of the data matrix.

Parameters:

Returns:

  • Network — The connectivity information in form of a network structure.

Example​

Used in examples​

ex_connectivity_metrics​

Connectivity metrics on synthetic data with a known coupling.

src/examples/ex_connectivity_metrics/main.cpp, line 234
const double cor01 = edgeWeight(correlation, 0, 1);
Network crossCorrelation = CrossCorrelation::calculate(settings);
const double xcor01 = edgeWeight(crossCorrelation, 0, 1);
// Zero-lag Pearson r of the model: 0.5 cos(2 pi 10 Hz 12 ms) / sqrt(0.75 * 1.0) = 0.42
ok &= expect(std::fabs(cor01 - 0.42) < 0.05 && std::fabs(edgeWeight(correlation, 0, 2)) < 0.1,
             QString("COR 0-1 %1 within 0.05 of 0.42, |0-2| < 0.1").arg(cor01));
ok &= expect(xcor01 > 2.0 * std::fabs(edgeWeight(crossCorrelation, 0, 2)),
             QString("XCOR 0-1 %1 > 2 x |0-2|").arg(xcor01));

Authors of this file​