systemdynamics.sty

% Systemdynamics package with some useful shortcuts (so far only diagrams)
% Author: Ingmar Vierhaus
\NeedsTeXFormat{LaTeX2e}[1994/06/01]
\ProvidesPackage{systemdynamics}[2013/01/13 Custom Package]

\RequirePackage{ifthen}
\RequirePackage{tikz}
\RequirePackage{pgfplots}

\usetikzlibrary{shapes, shapes.geometric, arrows, decorations.markings}
\usetikzlibrary{positioning}
\pgfplotsset{compat=newest} 


\tikzstyle{stock} = [rectangle, minimum width=2cm, minimum
height=0.5cm,text centered, draw=black, fill=black!01, align=center, inner
ysep=1em] \tikzstyle{sdvariable} = []
\tikzstyle{sdcloud} = [cloud, draw,cloud puffs=8,cloud puff arc=150, aspect=1.5,
scale=0.5, inner ysep=1em, fill=white] 
\tikzstyle{arrow} = [thick	,->,>=stealth]
% Styles for the hourglass             
\tikzstyle{triangle} = [draw=black, regular polygon, regular
    polygon sides=3 ,scale=0.6]
\tikzstyle{border rotated} = [shape border rotate=180]
% Double arrow credits to Dominik Haumann
% http://www.texample.net/tikz/examples/double-arrows/
\tikzstyle{flow} = [thick, decoration={markings,mark=at position
   1 with {\arrow[semithick]{open triangle 60}}},
   double distance=1.4pt, shorten >= 5.5pt,
   preaction = {decorate},
   postaction = {draw,line width=1.4pt, white,shorten >= 4.5pt}]
\tikzstyle{sdarrow} = [->, shorten >=2pt]

%Draws a flow between the given nodes
% \flow{startnode}{endnode}{flow label}
\newcommand{\flow}[3] {
\draw[flow] ({#1}) to node[below=0.3cm] {{#3}} 
						node[thin, triangle, border rotated, above] (testnode) {}	
						node[thin, triangle, below] {} 
						({#2});
}
	
%Draws an ingoing flow (including cloud) for the given node
% \flow{node}{flow label}
\newcommand{\flowIn}[2] {
\node [sdcloud, left=5em of #1] (in_cloud_#1) {};
\draw[flow] (in_cloud_#1) to node[below=0.3cm] (in_#1_down) {{#2}} 
						node[thin, triangle, border rotated, above] (in_#1_up) {}	
						node[thin, triangle, below] (in_#1_down_nolabel) {} 
						({#1});
}

%Draws an outgoing flow (including cloud) for the given node
% \flow{node}{flow label}
\newcommand{\flowOut}[2] {
\node [sdcloud, right=5em of #1] (out_cloud_#1) {};
\draw[flow] ({#1}) to node[below=0.3cm] (out_#1_down) {{#2}} 
						node[thin, triangle, border rotated, above] (out_#1_up) {}	
						node[thin, triangle, below] (out_#1_down_nolabel)  {} 
						(out_cloud_#1);
}

%Draws an arrow indication functional dependency
\newcommand{\sdarrow}[3] {
\ifthenelse{\equal{#3}{}}{
\draw[sdarrow] ({#1}) to ({#2});
}{
\draw[sdarrow, #3] ({#1}) to ({#2});
}
}