65 lines
1.4 KiB
TeX
65 lines
1.4 KiB
TeX
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% nouveau 27 septembre 2020
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%
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\chapter{Gnuplot}
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\index{Gnuplot}\label{chap:gnuplot}
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Gnuplot - an interactive plotting program
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There is an on-line demo collection at http://gnuplot.info/demo
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% -------------------------------------------------------------------
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\section{Exemple : le phytotron}
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\index{phytotron}
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\begin{verbatim}
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#!/bin/bash
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# THIS IS A KLUDGE
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nbsamp=3000 # nombre d'echantillon
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if [ $# -eq 1 ]; then
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nbsamp=$1
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fi
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DATAFILE="serial/foo.dat"
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IMAGE="graphe.png"
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TMPFILE="/dev/shm/tmpdata"
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tail -${nbsamp} < ${DATAFILE} > ${TMPFILE}
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gnuplot << __EOC__
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set term png size 1600,800
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set output "${IMAGE}"
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set ytics 2
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set xtics
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set grid front
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set title "* Temperatures du Phytotron *"
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set xdata time
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set timefmt "%s"
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set format x "%b %d\n%H:%M"
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set yrange [ 10.0 : 40.0 ]
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plot "${TMPFILE}" using 1:3 title " inside" with lines, \
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"${TMPFILE}" using 1:4 title "ambient" with lines
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__EOC__
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display ${IMAGE} &
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\end{verbatim}
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% -------------------------------------------------------------------
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\section{Questions}
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Supposons que nous ayons sous le coude un fichier contenant
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\emph{six cent mille} lignes de données, qui ne représentent que
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trente secondes d'enregistrement d'une valeur de Virgo\index{Virgo},
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comment faire pour plotter les échantillons $N$ à $N+42$ ?
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% -------------------------------------------------------------------
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