[pstricks] Power Balance Schemes

[Herbert Voss]

Matteo Gattanini wrote:
> In "Politecnico of Milan" we sometimes describe power balances with 
> graphical schemes representing the power main flux and losses.
> LaTeX and PStricks give a good way to automate the drawing of such 
> schemes; the following code seems to work, and perhaps may be useful for 
> someone (even if it can be improved).
> An annoying thing is that isn't possible to put PS code in `nodesep' 
> option; to perform some multiplications `fp.sty' is loaded, I don't find 
> a better way. How can be avoided the use of additional calculation 
> packages?

use dimension registers

Herbert


\documentclass{report}
\usepackage{amsmath}
\usepackage{pstricks,pst-node}
\SpecialCoor
%___ POWER SCHEME ___
%
%      \begin{PSpic_PowSch}{`width'}{`height'}{`label pow-in'}{`label 
pow-out'}
%          \PowLoss[`inter pow flux label']{`relative horizontal 
position'}{`loss relative amount'}{`label'}
%          ...
%      \end{PSpic_PowSch}
%
\makeatletter
\newcommand{\PowLoss}[4][ ]{%
%                               CALCULATIONS NEEDED: NO PS IN `nodesep'
	\pst at dimb=#2pt\pst at dima=\Lrgh\pst at dimb
	\def\DeltaX{\pst at number\pst at dima}
	\pst at dimc=#3pt\pst at dimd=\PW\pst at dimc
	\edef\DeltaY{\pst at number\pst at dimd}
	\pst at dimc=.5\pst at dimd
     \def\HalfDeltaY{\strip at pt\pst at dimc}
	\pst at dimc=\rCur\pst at dimd
     \def\SmallRadius{\strip at pt\pst at dimc}
	\pst at dimc=\rLarr\pst at dimd
     \def\ArrowFly{\strip at pt\pst at dimc}
	\pst at dimc=\rHarr\pst at dimd
     \def\ArrowPeak{\strip at pt\pst at dimc}
%                               NODE DEFINITIONS
     \pnode(CurPoint){PrevPoint}
     \pnode(\DeltaX,0|PrevPoint){PointRelX}
     \pnode([nodesep=\DeltaY,angle=-90]PrevPoint){PointRelY}
     \pnode(PointRelX|PointRelY){CurPoint}
     \pnode([nodesep=\SmallRadius,angle=90]PointRelX){PointRadius}
     \pnode([nodesep=\SmallRadius,angle=0]PointRadius){PointOne}
     \pnode([nodesep=\ArrowFly,angle=180]PointOne){PointTwo}
     \pnode([nodesep=\DeltaY,angle=0]PointOne){PointThree}
     \pnode([nodesep=\ArrowFly,angle=0]PointThree){PointFour}
 
\pnode([nodesep=\HalfDeltaY,angle=0]PointOne|[nodesep=\ArrowPeak,angle=90]PointOne){PointPeak}
%                               DRAWING ARROW
     \psline(PrevPoint)(PointRelX)
     \ncarc[arcangle=-45]{-}{PointRelX}{PointOne}
     \ncarc[arcangle=-45]{-}{CurPoint}{PointThree}
     \psline(PointOne)(PointTwo)(PointPeak)(PointFour)(PointThree)
     \nput[labelsep=.2]{90}{PointPeak}{#4}% loss label
%                               OPTIONAL POWER FLUX LABEL
     \ifx#1 \relax % if no label do nothing
 
\else\ncline[linestyle=none]{-}{PrevPoint}{PointRelX}\ncput{\pnode{MPointUp}}
          \pnode(MPointUp|0,0){MPointDwn}
 
\ncline[linestyle=solid,linewidth=.5pt,nodesep=.05]{<->}{MPointUp}{MPointDwn}\naput{#1}\fi
}
\newenvironment{PSpic_PowSch}[4]{% >>> OPENING ENVIRONMENT
     \psset{unit=1cm,linestyle=solid,linewidth=.035}
%                               DIMENSIONAL PARAMETERS DEFINITION
     \def\Lrgh{#1}\def\Altz{#2}% PSpicture dimensions
     \def\Hcoeff{.65}
	\pst at dimc=\Hcoeff pt\pst at dimd=\Altz\pst at dimc
	\edef\PW{\pst at number\pst at dimd}% pow-in relative value (`fp.sty' needed)
     \def\rHarr{.8}\def\rLarr{.35}% loss arrows relative dimensions
     \def\rCur{1}% arrows curvature radius relative value
     \def\Punta{.5}% in-out peak dimension
%                               PICTURE
     \begin{pspicture}(\Lrgh,\Altz)
         \pnode(!0 \Hcoeff\space \Altz\space mul){StartPoint}
         \pnode(StartPoint){CurPoint}
         \pnode(!\Punta\space \Hcoeff\space \Altz\space mul 2 div){MiddleSx}
         \psline(0,0)(MiddleSx)(StartPoint)
         \nput[labelsep=.3]{0}{MiddleSx}{#3}% pow-in label
         \def\potUlabel{#4}}% pow-out label
                                 {% >>> CLOSING ENVIRONMENT
         \pnode(\Lrgh,0){ExtPointDxDown}
         \pnode(ExtPointDxDown|CurPoint){ExtPointDxUp}
 
\ncline[linestyle=none]{-}{ExtPointDxUp}{ExtPointDxDown}\ncput{\pnode{MiddleDx}}
 
\psline(CurPoint)([nodesep=\Punta,angle=180]ExtPointDxUp)(MiddleDx)%
                ([nodesep=\Punta,angle=180]ExtPointDxDown)(0,0)
         \newlength{\ObjWidth}\settowidth{\ObjWidth}{\potUlabel}
         \pnode([nodesep=\ObjWidth,angle=180]MiddleDx){LabelDx}
         \nput[labelsep=-.3]{0}{LabelDx}{\potUlabel}
     \end{pspicture}}
\makeatother
%¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
\begin{document}
In figure~\ref{fig:power-scheme} there's the output; the choosed 
dimensions are \(12cm \times 6cm\).
\begin{figure}[h]\centering
     \begin{PSpic_PowSch}{12}{6}{\(P_e\)}{\(P_u\)}
         \PowLoss{.18}{.12}{\(R_s \, I_s2\)} % Joule
         \PowLoss{.35}{.08}{\(G_{Fe} \, E_s^{\phantom{.}2}\)} % iron
         \PowLoss[\(P_{tr}=\dfrac{\omega}{n} C_e\)]{.62}{.13}{\(R_R \, 
I_r2\)} % Joule
         \PowLoss[\(\dfrac{\omega_m}{n} C_e\)]{.79}{.09}{\textit{attr}} 
% mec
     \end{PSpic_PowSch}
     \caption{A power scheme for the asyncronous 
motor}\label{fig:power-scheme}
\end{figure}
\end{document}



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