\documentclass[pstricks]{standalone} \usepackage{pst-contourplot,pst-math,multido} \begin{document} % 4 dipôles de Hertz aux sommets d'un carré % dont les sommets se rapprochent \multido{\rX=1.1+-0.05}{22}{% \begin{pspicture}(-6.25,-6.25)(6.25,6.25) \pstVerb{/t 0 def /k0 2 PI mul def /xi1 -\rX\space def /xi2 \rX\space def /xi3 -\rX\space def /xi4 \rX\space def /yi1 -\rX\space def /yi2 \rX\space def /yi3 \rX\space def /yi4 -\rX\space def}% \psframe*[linecolor=yellow](-6.25,-6.25)(6.25,6.25) \multido{\rc=-1.1+0.2,\n=0.0+0.1}{11}{ \definecolor{HERTZ}{hsb}{\n,1,1} \psContourPlot[unit=5,a=0.0125,linewidth=0.005,fillcolor=HERTZ,Fill,ReverseColors,linecolor=HERTZ, function= /r1 x xi1 sub dup mul y yi1 sub dup mul add sqrt k0 mul def /theta1 y yi1 sub x xi1 sub atan def /r2 x xi2 sub dup mul y yi2 sub dup mul add sqrt k0 mul def /theta2 y yi2 sub x xi2 sub atan def /r3 x xi3 sub dup mul y yi3 sub dup mul add sqrt k0 mul def /theta3 y yi3 sub x xi3 sub atan def /r4 x xi4 sub dup mul y yi4 sub dup mul add sqrt k0 mul def /theta4 y yi4 sub x xi4 sub atan def r1 t sub COS r1 t sub SIN r1 div add theta1 sin dup mul mul r2 t sub COS r2 t sub SIN r2 div add theta2 sin dup mul mul add r3 t sub COS r3 t sub SIN r3 div add theta3 sin dup mul mul add r4 t sub COS r4 t sub SIN r4 div add theta4 sin dup mul mul add \rc\space sub](-1.25,-1.25)(1.25,1.25)}% \end{pspicture}} \end{document}