</p><p>The structure of a recurrence function is consistent, so the recurrence function with a corridor threshold — given by the equation below</p><p class="math-container">\[\mathbf{R}_{ij}=\Theta(\|\mathbf{x}_i-\mathbf{x}_j\|-\varepsilon_{min})\cdot\Theta(\varepsilon_{max} -\|\mathbf{x}_i-\mathbf{x}_j\|), \]</p><p>was implemented as follows in Julia:</p><pre><code class="language-julia hljs">@inline function recurrence(x::Matrix{Float64}, y::Matrix{Float64}, thresholds::Tuple{Float64, Float64}, idx::Abs