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This is an old version, <a href="https://mc-stan.org/docs/functions-reference/removed_functions.html#fabs-function">view current version</a>.
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<h2><span class="header-section-number">13.10</span> <code>abs(real x)</code> Function</h2>
<p><em>Deprecated</em>: Use of the <code>abs</code> function with real-valued ar