I am newbie in tikz and I would like to create a contour for a math document. Is it possible to produce the following diagram in tikz? If not, could you tell me an 'easy' solution other than the inclusion of the image with graphicx.
Thank you!
I am newbie in tikz and I would like to create a contour for a math document. Is it possible to produce the following diagram in tikz? If not, could you tell me an 'easy' solution other than the inclusion of the image with graphicx.
Thank you!
It's not so hard with TikZ, it just requires some learning and working with it. Here is code for you to start, inspired by Gonzalo, follow the Link given by Alan to learn more.
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations.markings}
\begin{document}
\begin{tikzpicture}[decoration={markings,
mark=at position 1cm with {\arrow[line width=1pt]{stealth}},
mark=at position 4.5cm with {\arrow[line width=1pt]{stealth}},
mark=at position 7cm with {\arrow[line width=1pt]{stealth}},
mark=at position 9.5cm with {\arrow[line width=1pt]{stealth}}
}]
\draw[thick, ->] (-2,0) -- (4,0) coordinate (xaxis);
\draw[thick, ->] (0,-3) -- (0,4) coordinate (yaxis);
\node[below] at (xaxis) {$\mathrm{Re}(s)$};
\node[left] at (yaxis) {$\mathrm{Im}(s)$};
\path[draw,blue, line width=0.8pt, postaction=decorate] (0,3)
-- node[midway, above, black] {$C_1$} (3,3)
-- node[midway, right, black] {$C_N$}(3,-2)
-- node[midway, below, black] {$C_2$} (0,-2);
\end{tikzpicture}
\end{document}
If you think you can solve your task using TikZ now, you could go ahead and extend it.
Many thanks Stefan. I have now a nice tikz code for my contour:
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations.markings}
\begin{document}
\begin{tikzpicture}
\draw[thick, ->,color=gray] (-2,0) -- (4,0) coordinate (xaxis);
\draw[thick, ->,color=gray] (0,-3) -- (0,4) coordinate (yaxis);
\node[below] at (xaxis) {$\mathrm{Re}(s)$};
\node[right] at (yaxis) {$\mathrm{Im}(s)$};
\path[draw,blue, line width=0.8pt] (0,3)
--(3,3) node[midway, above, black] {$C_1$}
node[pos=0.3,black]{$>$}
--(3,-2) node[pos=0.4, right, black] {$C_N$}
node[pos=0.3,black,rotate=-90]{$>$}
node[pos=0.53, right, black] {$N+\frac 1 2$}
node[pos=0.8,black,rotate=-90]{$>$}
--(0,-2) node[pos=0.4, below, black] {$C_2$}
node[pos=0.5,black]{$<$}
node[left,black] {$N$}
--(0,-1.2) node[pos=0.4,black,rotate=+90]{$>$}
--(0.45,-1.2) node[pos=0.6,black]{$>$}
arc(-90:0:0.2) node[black,rotate=90]{$>$}
node[right,black]{$-b$}
arc(0:90:0.2)
--(0,-0.8) node[pos=0.5,black]{$<$}
--(0,-0.2) node[pos=0.4,black,rotate=90]{$>$}
arc(270:180:0.2) node[black,rotate=90]{$>$} arc(180:90:0.2)
--(0,2) node[pos=0.4,black,rotate=90]{$>$}
node[pos=0.6,black,right]{$C$}
--(1.35,2) node[pos=0.5,black]{$>$}
arc(-90:0:0.2) node[black,rotate=90]{$>$}
node[right,black]{$-a$}
arc(0:90:0.2)
--(0,2.4) node[pos=0.5,black]{$<$}
--(0,3) node[pos=0.5,black,rotate=90]{$>$}
node[black,left]{$N$};
% Les poles en y=-b
\foreach \x in {0.45,0.15,...,-1.05} {
\draw[thick,line width=1.5pt](\x-0.07,-1-0.07)--(\x+0.07,-1+0.07);
\draw[thick,line width=1.5pt](\x+0.07,-1-0.07)--(\x-0.07,-1+0.07);
}
% Les poles sur l'axe reel
\foreach \x in {0,0.3,...,2.1} {
\draw[thick,line width=1.5pt](\x-0.07,-0.07)--(\x+0.07,+0.07);
\draw[thick,line width=1.5pt](\x+0.07,-0.07)--(\x-0.07,+0.07);
}
\draw (2.3,0) node[rectangle,fill=white]{$\backslash\backslash$};
\foreach \x in {2.8,3.2} {
\draw[thick,line width=1.5pt](\x-0.07,-0.07)--(\x+0.07,+0.07);
\draw[thick,line width=1.5pt](\x+0.07,-0.07)--(\x-0.07,+0.07);
}
% Les poles en y=-a
\foreach \x in {1.35,1.05,...,-1.05} {
\draw[thick,line width=1.5pt](\x-0.07,2.2-0.07)--(\x+0.07,2.2+0.07);
\draw[thick,line width=1.5pt](\x+0.07,2.2-0.07)--(\x-0.07,2.2+0.07);
}
\end{tikzpicture}
\end{document}