n <span class="math inline">\(x\mapsto \mu + \sigma * x\)</span> with offset <span class="math inline">\(\mu\)</span> and
(positive) multiplier <span class="math inline">\(\sigma\)</span>, using a syntax similar to
that for bounds.
While these transforms do not change the asymptotic sampling behaviour of
the resulting Stan program (in a sense, the model the program implements),
they can be useful for making the sampling process
more efficient by transforming the geometry of the problem to a more natural
mul