Internal workhorse called by dyn_phase_lock(). Iterates over the trimmed
timepoints (dropping the first and last 10) and fills an [N, N, n_T]
array with \(\cos(\phi_i - \phi_j)\) for every parcel pair.
Usage
dyn_phase_lock_cpp(phases)
Arguments
- phases
NumericMatrix [N x Tmax]. Instantaneous phases in radians,
as returned by hilbert_phases().
Value
A NumericVector with a dim attribute [N, N, n_T] (i.e. a
3-D array), where n_T = Tmax - 20.
Details
Exploits the symmetry \(\cos(a-b) = \cos(b-a)\): only the upper triangle
is computed via std::cos; the diagonal is set to 1 directly, and
values are mirrored to the lower triangle. This halves the number of
trigonometric evaluations relative to a naive double loop.
