 the function \(\tau(\cdot)\)<a class="anchor" aria-label="anchor" href="#specifying-the-function-tau-cdot-"></a></h2>


<p>This function is the <code>f_param</code> argument and should be a function that either: 1)
takes a vector of length sum(d_j) (the total number of bins) and outputs a single number, or 2) takes a
matrix with number of columns equal to sum(d_j), and arbitrary number of rows and
outputs a vector with length equal to the number of rows. In other words, psi can be
not vectorized or it can 