Eixos apontando em ambas as direções e rótulos de eixos de posicionamento (Tikz). Diagrama AD-AS

Question

Gostaria de reproduzir um gráfico como este mas não sei fazer o eixo como na foto. Alguém sabe como? Um exemplo semelhante que não tem eixo apontando para os dois lados é:

% Author: Rasmus Pank Roulund
\documentclass{minimal}
\usepackage{tikz}
\usepackage{verbatim}

\begin{comment}
:Title: Intersection of
:Tags: Coordinate systems


This example shows how the ``intersection of`` mechanism of Tikz work. Notice how a horizontal 
line is made from point B to allow the calculation to be done.

Caption: In a fixed exchange regime it might not be possible to reach internal balance 
(full employment and price stability) and external balance (some given level of net export) 
using only fiscal policy. At point B only point C and D can be reached via fiscal policy. 
Only by devaluing the country is able to reach the optimum level at point A.

:Author: Rasmus Pank Roulund

\end{comment}
\usetikzlibrary{arrows}
\begin{document}
\begin{tikzpicture}[
    scale=5,
    axis/.style={very thick, ->, >=stealth'},
    important line/.style={thick},
    dashed line/.style={dashed, thin},
    pile/.style={thick, ->, >=stealth', shorten <=2pt, shorten
    >=2pt},
    every node/.style={color=black}
    ]
    % axis
    \draw[axis] (-0.1,0)  -- (1.1,0) node(xline)[right]
        {$G\uparrow/T\downarrow$};
    \draw[axis] (0,-0.1) -- (0,1.1) node(yline)[above] {$E$};
    % Lines
    \draw[important line] (.15,.15) coordinate (A) -- (.85,.85)
        coordinate (B) node[right, text width=5em] {$Y^O$};
    \draw[important line] (.15,.85) coordinate (C) -- (.85,.15)
        coordinate (D) node[right, text width=5em] {$\mathit{NX}=x$};
    % Intersection of lines
    \fill[red] (intersection cs:
       first line={(A) -- (B)},
       second line={(C) -- (D)}) coordinate (E) circle (.4pt)
       node[above,] {$A$};
    % The E point is placed more or less randomly
    \fill[red]  (E) +(-.075cm,-.2cm) coordinate (out) circle (.4pt)
        node[below left] {$B$};
    % Line connecting out and ext balances
    \draw [pile] (out) -- (intersection of A--B and out--[shift={(0:1pt)}]out)
        coordinate (extbal);
    \fill[red] (extbal) circle (.4pt) node[above] {$C$};
    % line connecting  out and int balances
    \draw [pile] (out) -- (intersection of C--D and out--[shift={(0:1pt)}]out)
        coordinate (intbal);
    \fill[red] (intbal) circle (.4pt) node[above] {$D$};
    % line between out og all balanced out :)
    \draw[pile] (out) -- (E);
\end{tikzpicture}
\end{document}

Editar: Meu código atual é:

\usetikzlibrary{arrows}
\begin{document}
\begin{tikzpicture}[
    scale=5,
    axis/.style={very thick, <->, >=stealth'},
    important line/.style={thick},
    every node/.style={color=black}
    ]
    % axis
    \draw[axis] (0.1,0)  -- (1.1,0) node(xline)[right] {$Y$};
    \draw[axis] (0,0.1) -- (0,1.1) node(yline)[above] {$\pi_s$};
    % Lines
    \draw[important line] (.15,.15) coordinate (A) -- (.85,.85)
        coordinate (B) node[right, text width=5em] {$AS$};
    \draw[important line] (.15,.85) coordinate (C) -- (.85,.15)
        coordinate (D) node[right, text width=5em] {$AD$};
\end{tikzpicture}
\end{document}

Saúde,

Fábio

Solução: Para quem está interessado em um diagrama AD-AS, foi isso que consegui até agora. Eu acho que é bastante decente:

\documentclass{minimal}
\usepackage{tikz}
\usepackage{verbatim}
\usetikzlibrary{arrows}
\begin{document}
\begin{tikzpicture}[
    scale=5,
    axis/.style={very thick, <->, >=stealth'},
    important line/.style={thick},
    every node/.style={color=black}
    ]
    % axis
    \draw[axis] (0.1,0)  -- (1.1,0) node(xline)[midway,below] {$\hat{Y}$};
    \draw[axis] (0,0.1) -- (0,1.1) node(yline)[midway,left] {$  \hat{\pi}_s$};
    % Lines
    \draw[important line] (.15,.15) coordinate (A) -- (.85,.85)
        coordinate (B) node[right, text width=5em] {$AS$};
    \draw[important line] (.15,.85) coordinate (C) -- (.85,.15)
        coordinate (D) node[right, text width=5em] {$AD$};
    %shifted IS-LM diagram
    \draw[xshift=.2cm, red!52] (.15,.10) coordinate (A) -- (.85,.80)
    coordinate (B) node[right, text width=5em] {$AS'$};

    %arrows between intersections
    \draw[->, thick, black, >=stealth']
    (0.61,.59) -- (.72,.48)
    node[sloped, above, midway] {$\hat{\tau}^w_S$};
\end{tikzpicture}
\end{document}

Answer 1

Para obter pontas de seta em ambas as extremidades, use <->em vez de ->.

Para escrever um rótulo acima do meio de uma seta use

\draw (0,0) -- (5,0) node[midway,above]{A};

midwayé um apelido para pos=0.5.