[Tex/LaTex] Upright Lowercase $\pi$

Question

On pg. 144 of Kopka and Daily's A Guide to LaTeX, they mention that the symbols $e$, $i$, $d$, and $\pi$ should be displayed upright in math mode (for their usual uses). This is easy to do for $e$, $i$, and $d$: just use \mathrm. However, this does nothing to \pi. How exactly do you generate an upright \pi in math mode?

Answer 1

One option could be to use \uppi from the upgreek package:

\documentclass{article}
\usepackage{upgreek}

\begin{document}

$\uppi$

$\pi$

\end{document}

Here's the upright symbol using the Symbol package option:

\documentclass{article}
\usepackage[Symbol]{upgreek}

\begin{document}

$\uppi$

$\pi$

\end{document}

and now using the Symbolsmallscale package option:

\documentclass{article}
\usepackage[Symbolsmallscale]{upgreek}

\begin{document}

$\uppi$

$\pi$

\end{document}