Drawing a dataflow using tikz

graphstikz-pgf

I'm trying to draw the following dataflow diagram in tikz:

Here is what I got so far:

\documentclass[10pt,a4paper]{article}
\usepackage[english]{babel}
\usepackage[utf8]{inputenc}

\usepackage{tikz}
\usetikzlibrary{decorations.markings,positioning,petri}

\begin{document}
\begin{tikzpicture}[thick,
    node distance=2cm,
    on grid,
    every transition/.style={fill=black,minimum width=.1cm, minimum height=0.9cm},
    every label/.style={black!75}]
    node distance=2cm,
    on grid,
    every transition/.style={fill=black,minimum width=.1cm, minimum height=0.9cm},
    every label/.style={black!75}]
  \node[place, label=above:$n_1$] (n1) {+};
  \node[place, right=of n1, label=above:$n_2$] (n2) {$\times 2$};
  \node[place, right=of n2, label=above:$n_3$] (n3) {+};
  \node[place, below=of n2, label=above:$n_4$] (n4) {+1};
  \node[place, right=of n3, label=above:$n_5$] (n5) {$\Delta(0)$};
  \node[right of=n5] (x) {X};
  \node[below of=n5] (y) {Y};
  \node[left of=n1] (i) {Input};

  \draw[->] (n1) edge (n2.west);
  \draw[->] (n2) edge (n3.west);
  \draw[->, to path={-| (\tikztotarget)}] (n4) edge (n3.south);
  \draw[->] (n3) edge (n5.west);
  \draw[->] (n5) edge (x);
  \draw[->] (n4) edge (y);
  \draw[->] (i) edge (n1.west);
  \draw[->, to path={|- (\tikztotarget)}] (i) edge (n4.west);
\end{tikzpicture}
\end{document}

As you can see, drawing the nodes work fine but I'm having trouble getting the edges right. I want the edges to be angled and also there to be dots so it's clear where the flow branches.

I updated my code with edge drawing commands. I still cannot get the feedback edge right nor do I get dots where the edges branches.

Best Answer

Try the following:

%\documentclass[10pt,a4paper]{article}
\documentclass[border=3.141592mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,
                chains,
                decorations.markings,
                positioning,
                shadows, }

\begin{document}
    \begin{tikzpicture}[
node distance = 7mm and 11mm,
  start chain = A going right,
     C/.style = {circle, minimum size=11mm, inner sep=1pt, outer sep=0pt,
                 draw, semithick, fill=gray!30},
   dot/.style = {circle, fill, inner sep=2pt, outer sep = 0pt,
                 node contents={}},
every label/.style = {font=\small\sffamily},
 every path/.style = {-Straight Barb}
                        ] 
\coordinate[label=above right:input] (in);
\node (d1) [dot, right=of in];
    \begin{scope}[nodes = {C, on chain=A, join=by ->}] 
\node (n1) [C, right=of d1]   {+};  % A-1
\node (n2) [C]   {$\times 2$};
\node (n3) [C]   {+};
\node (n4) [C]   {$\Delta(0)$};     % A-4
    \end{scope}
\node (d2) [dot, right=of A-4];
\coordinate[right=of d2, label=above left:X] (x);
%
\node (A-5) [C, below=of A-2] {+1};
\node (d3)  [dot, at={(A-5 -| A-3)}];
\coordinate[right=of d3, label=above left:Y] (y);
%
\draw   (d2) |- ([yshift=7mm] A-1.north) edge (A-1)
        (in) to (A-1) (d3) edge (A-3)   (A-4) edge (x)
        (A-5) edge (y);
\draw   (d1) |- (A-5);
\end{tikzpicture}
\end{document}

Edit: Ar adding labels the chain had to be handled different as above: it should be add to C nodes style. Doing this, macro join had to be interrupted because it should not connect last Cnode in code with others. In this case thescope` is not needed anymore.

\documentclass[border=3.141592mm]{standalone}
\usepackage{tikz}
\usetikzlibrary{arrows.meta,
                backgrounds,
                chains,
                positioning}
\makeatletter
\tikzset{suspend join/.code={\def\tikz@after@path{}}}
\makeatother

\begin{document}
    \begin{tikzpicture}[
node distance = 7mm and 11mm,
  start chain = going right,
     C/.style = {circle, minimum size=11mm, inner sep=1pt, outer sep=0pt,
                 draw, semithick, fill=gray!30, drop shadow,
                 on chain, join= by ->},
   dot/.style = {circle, fill, inner sep=2pt, outer sep = 0pt,
                 node contents={}},
every label/.style = {label distance=5pt, inner sep=1pt, 
                      font=\small\sffamily, fill=white},
 every path/.style = {-Straight Barb}
                        ]
\coordinate[label=above right:input] (in);
\node (d1) [dot, right=of in];
\node (n1) [C,label=$n_1$,
            right=of d1]    {+};   
\node (n2) [C,label=$n_2$]  {$\times 2$};
\node (n3) [C,label=$n_3$]  {+};
\node (n4) [C,label=$n_4$]  {$\Delta(0)$}; 
\node (d2) [dot, on chain];
\coordinate[on chain, 
            label=above left:X] (x);
\node (n5) [C, suspend join,
            below=of n2,
            label=$n_5$]   {+1};
\node (d3) [dot, at={(n5 -| n3)}];
\coordinate[right=of d3, label=above left:Y] (y);
%
\scoped[on background layer]
\draw   (d2) |- ([yshift=7mm] n1.north) edge (n1)
        (in) to (n1) (d3) edge (n3)   (n4) edge (x)
        (n5) edge (y);
\draw   (d1) |- (n5);
    \end{tikzpicture}
\end{document}

Related Solutions

[Tex/LaTex] Rotate a node but not its content: the case of the ellipse decoration

The source of the difficulty is that ellipses are constructed in a particular way in TikZ. They are paths that start from the x-axis and proceed counter-clockwise around their centre. The vast majority of the time, the exact parametrisation doesn't matter. You appear to have found the one situation where it does!

In the actual question, you only want to be able to mirror the ellipse, and so draw it starting from the negative x-axis (the title of the question suggests a more flexible approach). That's actually not too hard since we can exploit the symmetry of the ellipse. The key is to provide it with a negative x-radius, since then it will start from the negative x-axis (and proceed clockwise, but we could correct for that by negating the y-radius as well). To do this, we interrupt the call from the node shape to the drawing command and flip the sign of the x-radius. The simplest way to do this is to redefine the \pgfpathellipse macro to do the negation and then call the original macro. The following code does this.

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations,shapes,decorations.markings}
\makeatletter
\let\origpgfpathellipse=\pgfpathellipse
\def\revpgfpathellipse#1#2#3{%
  #2%
  \pgf@xa=-\pgf@x
  \origpgfpathellipse{#1}{\pgfqpoint{\pgf@xa}{0pt}}{#3}}
\makeatother

\tikzset{
  reversed ellipse/.style={
    ellipse,
    reverse the ellipse%
  },
  reverse the ellipse/.code={
    \let\pgfpathellipse=\revpgfpathellipse
  }
}
\begin{document}
\begin{tikzpicture}
\node[ellipse,
  draw,
  postaction={
    decorate,
    decoration={
      markings,
      mark=at position 1 with {
        \arrow[line width=5pt,blue]{>}
      }
    }
  }
] at (0,0) {hello world};

\node[reversed ellipse,
  draw,
  postaction={
    decorate,
    decoration={
      markings,
      mark=at position 1 with {
        \arrow[line width=5pt,blue]{>}
      }
    }
  }
] at (0,-2) {hello world};
\end{tikzpicture}

\end{document}

Here's the result:

rotated ellipse

(the arrow got clipped, but you can see where it lies)

[Tex/LaTex] How to define the default vertical distance between nodes

I don't really get the question so I hope this is what you wanted. If you include a full document (such that we copy paste and see the problem on our systems) things are much more easier.

Here, you can change the default setting within a scope but your block style had a node distance which was resetting every time it is issued. I've made it 2mm such that we can see the difference easier.

\documentclass[tikz]{standalone}
\usetikzlibrary{arrows,shapes.geometric,positioning}

\begin{document}
\begin{tikzpicture}[decision/.style={diamond, draw, text width=4.5em, text badly centered, node distance=3.5cm, inner sep=0pt},
                    block/.style   ={rectangle, draw, text width=6em, text centered, rounded corners, minimum height=4em, minimum height=2em},
                    cloud/.style   ={draw, ellipse, minimum height=2em},
                    line/.style    ={draw,-latex'},
                    node distance = 1cm, 
                    auto]
    \node [block] (1st) {1st};
    \node [block, right= of 1st]  (2nd1) {2nd1};
\begin{scope}[node distance=2mm and 10mm]%Here we change it for everything inside this scope
    \node [block, above= of 2nd1] (2nd2) {2nd2};
    \node [block, below= of 2nd1] (2nd3) {2nd3};
    \node [block, right= of 2nd1] (3rd1) {3rd1};
    \node [block, above= of 3rd1] (3rd2) {3rd2};
    \node [block, above= of 3rd2] (3rd3) {3rd3};
\end{scope}
    \node [block, below= of 3rd1] (3rd4) {3rd4};
    \node [block, below= of 3rd4] (3rd5) {3rd5};

    \path [line] (1st) -- (2nd1);
    \path [line] (2nd1) -- (2nd2);
    \path [line] (2nd1) -- (2nd3);
    \path [line] (2nd2) -- (3rd3);
    \path [line] (2nd1) -- (3rd1);
    \path [line] (1st) -- (2nd1);
\end{tikzpicture}
\end{document}

enter image description here

Best Answer

Related Solutions

[Tex/LaTex] Rotate a node but not its content: the case of the ellipse decoration

[Tex/LaTex] How to define the default vertical distance between nodes

Related Question