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}

Answer 2

Without upgreek, babel supports upright Greek characters:

\documentclass{article}
\usepackage[greek,english]{babel}
\begin{document}
\newcommand{\gpi}{\textrm{\greektext p}}
$\gpi \theta$
\end{document}

(Taken from Upright Greek letters in text mode (not upgreek).)

Answer 3

From Will Robertson's blog one way is to use the mathpazo. Here is a comparison of the two:

\documentclass{article} 
\usepackage{mathpazo}
\DeclareSymbolFont{euler}{U}{eur}{m}{n}
\DeclareMathSymbol \uppi \mathalpha {euler} {"19}

\begin{document}
    $\pi \quad \uppi$
\end{document}

Answer 4

While upgreek works well for some fonts, it doesn't match perfectly with Computer Modern. Here are some alternatives:

• Use a different typeface for the document. For example BT Charter from mathdesign⁽¹⁾:

  \usepackage[T1]{fontenc}
  \usepackage[charter,cal=cmcal]{mathdesign}
  

• Use the text pi that you get when typing Greek text with e.g. babel:

  \usepackage[greek,english]{babel} % english = default
  \usepackage[LGR,T1]{fontenc}
  \usepackage{lmodern,amsmath,xspace}
  \def\PI{\ensuremath{\text{\foreignlanguage{greek}{p}}}\xspace}
  % Similar definitions can be made for the rest of the greek alphabet. 
  % Here's a conversion table:
  % Latin: a b g d e z h j i k l m n x o p r s t u f q y w 
  % Greek: α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ σ τ υ φ χ ψ ω 
  

  While this works it's really ugly and should obviously be done with \DeclareSymbolFont and \DeclareMathSymbol.

• Same as the above, but using the font bodoni instead. It's a Didone typeface, so it should match pretty well with Computer Modern.

(1): Note that mathdesign has some other design issues such as imperfect kerning, poorly drawn glyphs for blackboard bold letters and \middle\vert usually ends up being too high.

Answer 5

With Xe/LuaLaTeX, unicode-math and a proper OpenType Math font, upright πs (and many other symbols) are built in:

% compile with xelatex or lualatex
\documentclass{article}

\usepackage{unicode-math}
\setmathfont{lmmath-regular.otf}

\begin{document}
$π\ \mathrm{π}$
\end{document}