Generating tikz figure in latex

Question

I am trying to generate a tikz figure similar to

So far I made the following latex code:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{booktabs}
\usepackage{caption}
\usepackage{tikz}
\usetikzlibrary{positioning}

\tikzset{
  pics/BitArray/.style n args={2}{
  code={\begin{scope}[#2]
  \fill
    \foreach \row [count=\y] in {#1} {
      \foreach \cell [count=\x] in \row {
        \ifnum\cell=1 %
          (\x-1, -\y+1) rectangle ++(1, -1)
        \fi
        \pgfextra{%
          \global\let\maxx\x
          \global\let\maxy\y
        }%
      }
    }
  ;
  \draw[thin] (0, 0) grid[step=1] (\maxx, -\maxy);
  \end{scope}
  }
 }
}


\begin{document}
\[
\begin{tikzpicture}[scale=5]
[baseline=(N.base)]
\begin{scope}[local bounding box=BA1,scale=0.4]
 \foreach \y in {0.2,0.4,...,1.8} {
      \foreach \x in {0.2,0.4,...,1.2} {
          \pgfmathparse{0.9*rnd+0.01}
          \definecolor{MyColor}{rgb}{\pgfmathresult,\pgfmathresult,\pgfmathresult}
          \node[fill=MyColor,inner sep=0.4cm,outer sep=0pt,anchor=center] at (\x,\y) {}; 
      }
  }
  \draw[step=.2,help lines] (0,0) grid (1.4,2); 

\end{scope}  
\node[above=1pt of BA1] {$D$};
\node[left=1pt of BA1.north west] {$X$};
\node[left=1pt of BA1.west] (N) {$N$};
\end{tikzpicture}
~\sim~
\begin{tikzpicture}[baseline=(N2.base)]
\begin{scope}[local bounding box=BA2,scale=0.5]
 \pic[right=3cm of BA1.north east] {BitArray={%
    {1,1,1,1},
    {1,1,1,0},
    {1,0,1,1},
    {1,0,0,1},
    {1,1,0,0},
    {0,1,0,1},
    {0,0,1,0},
    {0,1,0,0},
    {0,0,0,0},
    {0,0,0,0}%
  }{fill=black,scale=0.5}};
\end{scope}  
\node[left=1pt of BA2.north west] {$\mathbf{Z}$};
\node[above=1pt of BA2] {$K$};
\node[left=1pt of BA2.west] (N2) {$N$};
\end{tikzpicture}
~\dots~*
\begin{tikzpicture}[scale=5][baseline=(dots.base)]
\begin{scope}[local bounding box=BA3,scale=0.4]
 \foreach \y in {0.2,0.4,...,0.6} {
      \foreach \x in {0.2,0.4,...,1.2} {
          \pgfmathparse{0.9*rnd+0.01}
          \definecolor{MyColor}{rgb}{\pgfmathresult,\pgfmathresult,\pgfmathresult}
          \node[fill=MyColor,inner sep=0.4cm,outer sep=0pt,anchor=center] at (\x,\y) {}; 
      }
  }
  \draw[step=.2,help lines] (0,0) grid (1.4,0.8); 

\end{scope} 
\node[below=1pt of BA3.south] (dots) {$\vdots$};
\end{tikzpicture}
\]
\end{document}

Any suggestion how to complete my figure?

Second question: How can I make for instance a gamma distribution just using tikz? Is it possible?

Answer 1

Here is a proposal. Your baselines were correct except you put them into separate [...] brackets. Other than that you may want to load the decorations.pathreplacing library for the braces and so on. (I had to move some nodes to the left since they'd interfere with the braces otherwise.)

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{booktabs}
\usepackage{caption}
\usepackage{tikz}
\usetikzlibrary{positioning,decorations.pathreplacing}

\tikzset{
  pics/BitArray/.style n args={2}{
  code={\begin{scope}[#2]
  \fill
    \foreach \row [count=\y] in {#1} {
      \foreach \cell [count=\x] in \row {
        \ifnum\cell=1 %
          (\x-1, -\y+1) rectangle ++(1, -1)
        \fi
        \pgfextra{%
          \global\let\maxx\x
          \global\let\maxy\y
        }%
      }
    }
  ;
  \draw[thin] (0, 0) grid[step=1] (\maxx, -\maxy);
  \end{scope}
  }
 }
}


\begin{document}
\[
\begin{tikzpicture}[scale=5,baseline=(N.base)]
\begin{scope}[local bounding box=BA1,scale=0.4]
 \foreach \y in {0.2,0.4,...,1.8} {
      \foreach \x in {0.2,0.4,...,1.2} {
          \pgfmathparse{0.9*rnd+0.01}
          \definecolor{MyColor}{rgb}{\pgfmathresult,\pgfmathresult,\pgfmathresult}
          \node[fill=MyColor,inner sep=0.4cm,outer sep=0pt,anchor=center] at (\x,\y) {}; 
      }
  }
  \draw[step=.2,help lines] (0,0) grid (1.4,2); 

\end{scope}  
\node[above=1pt of BA1] {$D$};
\node[left=10pt of BA1.north west] {$X$};
\node[left=10pt of BA1.west] (N) {$N$};
\path (BA1.north west) -- (BA1.south west) coordinate[pos=0.8] (aux);
\draw[line width=1pt,blue,fill=blue,fill opacity=0.2]
([xshift=-0.25pt,yshift=0.25pt]aux) rectangle ([xshift=0.25pt,yshift=-0.25pt]BA1.south east);
\draw[thick,decorate,decoration={brace,raise=3pt}] (BA1.south west) -- (aux)
node[midway,left=3pt]{$X_{w}$}; 
\draw[thick,decorate,decoration={brace,raise=3pt}]  (aux) -- (BA1.north west)
node[midway,left=3pt]{$X_{-w}$}; 
\end{tikzpicture}
~\sim~
\begin{tikzpicture}[baseline=(N2.base)]
\begin{scope}[local bounding box=BA2,scale=0.5]
 \pic[right=3cm of BA1.north east] {BitArray={%
    {1,1,1,1},
    {1,1,1,0},
    {1,0,1,1},
    {1,0,0,1},
    {1,1,0,0},
    {0,1,0,1},
    {0,0,1,0},
    {0,1,0,0},
    {0,0,0,0},
    {0,0,0,0}%
  }{fill=black,scale=0.5}};
\end{scope}  
\node[left=10pt of BA2.north west] {$\mathbf{Z}$};
\node[above=1pt of BA2] {$K$};
\node[left=10pt of BA2.west] (N2) {$N$};
\path (BA2.north west) -- (BA2.south west) coordinate[pos=0.8] (aux);
\draw[line width=1pt,blue,fill=blue,fill opacity=0.2]
([xshift=-0.25pt,yshift=0.25pt]aux) rectangle ([xshift=0.25pt,yshift=-0.25pt]BA2.south east);
\draw[thick,decorate,decoration={brace,raise=3pt}] (BA2.south west) -- (aux)
node[midway,left=3pt]{$Z_{w}$}; 
\draw[thick,decorate,decoration={brace,raise=3pt}]  (aux) -- (BA2.north west)
node[midway,left=3pt]{$Z_{-w}$}; 
\end{tikzpicture}
~\dots~*
\begin{tikzpicture}[scale=5,baseline=(dots.base)]
\begin{scope}[local bounding box=BA3,scale=0.4]
 \foreach \y in {0.2,0.4,...,0.6} {
      \foreach \x in {0.2,0.4,...,1.2} {
          \pgfmathparse{0.9*rnd+0.01}
          \definecolor{MyColor}{rgb}{\pgfmathresult,\pgfmathresult,\pgfmathresult}
          \node[fill=MyColor,inner sep=0.4cm,outer sep=0pt,anchor=center] at (\x,\y) {}; 
      }
  }
  \draw[step=.2,help lines] (0,0) grid (1.4,0.8); 

\end{scope} 
\node[below=1pt of BA3.south] (dots) {$\vdots$};
\end{tikzpicture}
\]
\end{document}