a);
  real u = uniform_rng(p_lb, p_ub);
  real y = mu + sigma * Phi(u);
  return y;
}</code></pre>
<p>To make this more robust, all variables shold be tested for
finiteness, <code>sigma</code> should be tested for positiveness, and
<code>lb</code> and <code>ub</code> should be tested to ensure the upper bound is
greater than the lower bound. While it may be tempting to compress
lines, the variable names serve as a kind of chunking of operations
and naming for readability; compare the multiple statement vers