Filled \Diamond-product sign

Question

I use the multiple \Diamond-product sign (\bDiamond) as described in sign for multiple $\Diamond$-product. Now, in addition, I would like to have a filled \Diamond-product sign, i.e. filled with black. Any suggestions?

Answer 1

With amssymb you have \blacklozenge:

\documentclass{article}
\usepackage{amssymb,graphicx}

\newcommand{\bDiamond}{\mathbin{\Diamond}}
\newcommand{\bLozenge}{\mathbin{\blacklozenge}}

\makeatletter
\newcommand\bigDiamond{\mathop{\mathpalette\bigDi@mond\relax}}
\newcommand\bigDi@mond[2]{%
  \vcenter{\hbox{\m@th
    \scalebox{\ifx#1\displaystyle 2\else1.2\fi}{$#1\Diamond$}%
  }}%
}
\newcommand\bigLozenge{\mathop{\mathpalette\bigL@zenge\relax}}
\newcommand\bigL@zenge[2]{%
  \vcenter{\hbox{\m@th
    \scalebox{\ifx#1\displaystyle 2\else1.2\fi}{$#1\blacklozenge$}%
  }}%
}
\makeatother

\begin{document}
\[
\bigoplus_{i=1}^n % just for comparison
\bigDiamond_{i=1}^n (a_i\bDiamond b_i)\quad
\textstyle\bigDiamond_{i=1}^n a_i\quad
\scriptstyle\bigDiamond_{i=1}^n a_i\quad
\scriptscriptstyle\bigDiamond_{i=1}^n a_i
\]
\[
\bigoplus_{i=1}^n % just for comparison
\bigLozenge_{i=1}^n (a_i\bLozenge b_i)\quad
\textstyle\bigLozenge_{i=1}^n a_i\quad
\scriptstyle\bigLozenge_{i=1}^n a_i\quad
\scriptscriptstyle\bigLozenge_{i=1}^n a_i
\]
\end{document}

Answer 2

And here the obligatory unicode-answer:

% arara: lualatex

\documentclass{article}
\usepackage{unicode-math}
\setmathfont{XITS-Math}
\usepackage{booktabs}

\begin{document}    
\begin{table}
    \centering
\begin{tabular}{lc}
    \toprule
    Unicode & Symbol\\
    \midrule
    \verb|U+2B26| & $\mdwhtdiamond$\\
    \verb|U+2B25| & $\mdblkdiamond$\\
    \verb|U+2B28| & $\mdwhtlozenge$\\
    \verb|U+2B27| & $\mdblklozenge$\\
    \verb|U+22C4| & $\smwhtdiamond$\\   
    \verb|U+2B29| & $\smblkdiamond$\\
    \verb|U+2B2B| & $\smwhtlozenge$\\
    \verb|U+2B2A| & $\smblklozenge$\\
    \verb|U+25C7| & $\mdlgwhtdiamond$\\
    \verb|U+25C6| & $\mdlgblkdiamond$\\
    \verb|U+2662| & $\diamondsuit$\\
    \verb|U+2666| & $\vardiamondsuit$\\
    \bottomrule
\end{tabular}
\end{table}    
If you can't decide, take $\blackinwhitediamond$ or a half version like these: $\diamondleftblack\diamondrightblack\diamondtopblack\diamondbotblack$    
\end{document}

Answer 3

You can use tikz to draw it. Here is a comparison of the filled in version along with the \Diamond

Notes:

• This version requires additional work to be able to scale as well as egreg's version for different math sizes.
• I defined a separate macro if a dash over it is desired. However, if you did not have other options that were required, I would define a starred variant of the macro \MyDiamond* to include the dash.

Code:

\documentclass{article}
\usepackage{amssymb,amsmath, graphicx}
\usepackage{tikz}
\newcommand{\sqdiamond}[1][fill=black]{\tikz [x=1.2ex,y=1.85ex,line width=.1ex,line join=round, yshift=-0.285ex] \draw  [#1]  (0,.5) -- (.5,1) -- (1,.5) -- (.5,0) -- (0,.5) -- cycle;}%
\newcommand{\sqdiamondDash}[1][fill=black]{%
    \tikz [x=1.2ex,y=1.85ex,line width=.1ex,line join=round, yshift=-0.285ex] 
        \draw  [#1]

            (0,.5) -- (.5,1) -- (1,.5) -- (.5,0) -- (0,.5) -- cycle
            (0,1.1) --  (1,1.1);
}%
\newcommand{\MyDiamond}[1][fill=black]{\mathop{\raisebox{-0.275ex}{$\sqdiamond[#1]$}}}
\newcommand{\MyDiamondDash}[1][fill=black]{\mathop{\raisebox{-0.275ex}{$\sqdiamondDash[#1]$}}}
\begin{document}
$a \Diamond b \MyDiamond c \MyDiamond[draw=red,fill=cyan] d \MyDiamondDash[draw=red,fill=cyan] e$
\end{document}

Answer 4

\documentclass[12pt]{article}
\usepackage[utf8]{inputenc} 
 \usepackage[x11names]{xcolor}

 \usepackage{amsmath,amssymb}
 \usepackage{array} 

\DeclareFontFamily{U}{mathb}{\hyphenchar\font45}
\DeclareFontShape{U}{mathb}{m}{n}{
<5><6><7><8><9><10>gen*mathbm
<10.95>mathbm10<12><14.4><17.28><20.74><24.88>mathbm12
}{}
\DeclareSymbolFont{mathb}{U}{mathb}{m}{n}
\DeclareFontSubstitution{U}{mathb}{m}{n}
\DeclareMathSymbol{\blackdiamond}{\mathbin}{mathb}{"0C}
\def\bluediamond{\mathbin{\color{SteelBlue3}\blackdiamond}}    
\def\bluelozenge{\mathbin{\color{SteelBlue3}\blacklozenge}}

\begin{document}

\renewcommand\arraystretch{1.5}    
\begin{tabular}{l l}
With \texttt{mathabx}:   &  $ a \bluediamond b $ \\
With \texttt{amssymb}:  & $ a \bluelozenge b $
\end{tabular}

 \end{document}