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</o:shapelayout></xml><![endif]--></head><body lang=FR link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hello,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I changed g/R to gsR and deltaP/B to deltaPsB=1. Attempts with gsR=1 …10 are solved correctly by Scilab. An oscillatory behaviour is found for g/R=10, and perhaps for g/R > deltaP/B (?). <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Denis<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>De :</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> arnaud dujeu [mailto:fangorn813@hotmail.com] <br><b>Envoyé :</b> jeudi 21 juillet 2011 11:26<br><b>À :</b> users@lists.scilab.org<br><b>Objet :</b> [scilab-Users] problem with scilab<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>Hi,<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>I've got a problem to solve a non linear differential equation, which is :<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>y1'=A*(1-sin(y2))/(pi/2-y2)-B*y1^2<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>y2'=y1<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><o:p> </o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>I'm using ode : <o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'><o:p> </o:p></span></p></div><div><pre><span style='font-size:10.5pt;font-family:Monospaced;color:#B01813'>function</span><span style='font-size:10.5pt;font-family:Monospaced'> <span style='color:#4A55DB'>[</span><b><span style='color:#834310'>Xprime</span></b><span style='color:#4A55DB'>]</span><span style='color:#5C5C5C'>=</span><u><span style='color:black'>VanDerPol</span></u><span style='color:#4A55DB'>(</span><b><span style='color:#834310'>t</span></b><span style='color:black'>, </span><b><span style='color:#834310'>X</span></b><span style='color:#4A55DB'>)</span><o:p></o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced'> <o:p></o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced'> <b><span style='color:#834310'>Xprime</span></b><span style='color:#4A55DB'>(</span><span style='color:rosybrown'>1</span><span style='color:#4A55DB'>)</span> <span style='color:#5C5C5C'>=</span> <b><span style='color:#834310'>X</span></b><span style='color:#4A55DB'>(</span><span style='color:rosybrown'>2</span><span style='color:#4A55DB'>)</span><o:p></o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced'> <b><span style='color:#834310'>Xprime</span></b><span style='color:#4A55DB'>(</span><span style='color:rosybrown'>2</span><span style='color:#4A55DB'>)</span> <span style='color:#5C5C5C'>=</span> <span style='color:black'>g</span><span style='color:#5C5C5C'>/</span><span style='color:black'>R</span><span style='color:#5C5C5C'>*</span><span style='color:#4A55DB'>(</span><span style='color:rosybrown'>1</span><span style='color:#5C5C5C'>-</span><span style='color:#32B9B9'>sin</span><span style='color:#4A55DB'>(</span><b><span style='color:#834310'>X</span></b><span style='color:#4A55DB'>(</span><span style='color:rosybrown'>1</span><span style='color:#4A55DB'>)))</span><span style='color:#5C5C5C'>/</span><span style='color:#4A55DB'>(</span><span style='color:orchid'>%pi</span><span style='color:#5C5C5C'>/</span><span style='color:rosybrown'>2</span><span style='color:#5C5C5C'>-</span><b><span style='color:#834310'>X</span></b><span style='color:#4A55DB'>(</span><span style='color:rosybrown'>1</span><span style='color:#4A55DB'>))</span><span style='color:#5C5C5C'>-</span><span style='color:black'>deltaP</span><span style='color:#5C5C5C'>/</span><span style='color:#4A55DB'>(</span><span style='color:black'>B</span><span style='color:#5C5C5C'>*</span><span style='color:#4A55DB'>(</span><span style='color:orchid'>%pi</span><span style='color:#5C5C5C'>/</span><span style='color:rosybrown'>2</span><span style='color:#5C5C5C'>-</span><b><span style='color:#834310'>X</span></b><span style='color:#4A55DB'>(</span><span style='color:rosybrown'>1</span><span style='color:#4A55DB'>)))</span><o:p></o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced'> <o:p></o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced;color:#B01813'>endfunction</span><span style='font-size:10.5pt;font-family:Monospaced'><o:p></o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced'><o:p> </o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced'> <span style='color:black'>t</span><span style='color:#5C5C5C'>=</span><u><span style='color:#AE5CB0'>linspace</span></u><span style='color:#4A55DB'>(</span><span style='color:rosybrown'>0</span><span style='color:black'>,</span><span style='color:rosybrown'>4</span><span style='color:black'>,</span><span style='color:rosybrown'>3000</span><span style='color:#4A55DB'>)</span><span style='color:black'>;</span> <span style='color:black'>X0</span><span style='color:#5C5C5C'>=</span><span style='color:#4A55DB'>[</span><span style='color:rosybrown'>85</span><span style='color:#5C5C5C'>*</span><span style='color:orchid'>%pi</span><span style='color:#5C5C5C'>/</span><span style='color:rosybrown'>180</span><span style='color:black'>;</span><span style='color:rosybrown'>0</span><span style='color:#4A55DB'>]</span><span style='color:black'>;</span><o:p></o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced'> <span style='color:#4A55DB'>[</span><span style='color:black'>u</span><span style='color:#4A55DB'>]</span><span style='color:#5C5C5C'>=</span><span style='color:#32B9B9'>ode</span><span style='color:#4A55DB'>(</span><span style='color:black'>X0,</span><span style='color:rosybrown'>0</span><span style='color:black'>,t,<u>VanDerPol</u></span><span style='color:#4A55DB'>)</span><span style='color:black'>;</span><o:p></o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced'><o:p> </o:p></span></pre><pre><u><span style='font-size:10.5pt;font-family:Monospaced;color:#AE5CB0'>plot</span></u><span style='font-size:10.5pt;font-family:Monospaced;color:#4A55DB'>(</span><span style='font-size:10.5pt;font-family:Monospaced;color:black'>t,u</span><span style='font-size:10.5pt;font-family:Monospaced;color:#4A55DB'>(</span><span style='font-size:10.5pt;font-family:Monospaced;color:rosybrown'>1</span><span style='font-size:10.5pt;font-family:Monospaced;color:black'>,</span><span style='font-size:10.5pt;font-family:Monospaced;color:#FFAA00'>:</span><span style='font-size:10.5pt;font-family:Monospaced;color:#4A55DB'>)</span><span style='font-size:10.5pt;font-family:Monospaced;color:#5C5C5C'>*</span><span style='font-size:10.5pt;font-family:Monospaced;color:rosybrown'>180</span><span style='font-size:10.5pt;font-family:Monospaced;color:#5C5C5C'>/</span><span style='font-size:10.5pt;font-family:Monospaced;color:orchid'>%pi</span><span style='font-size:10.5pt;font-family:Monospaced;color:black'>,</span><span style='font-size:10.5pt;font-family:Monospaced;color:rosybrown'>'r'</span><span style='font-size:10.5pt;font-family:Monospaced;color:#4A55DB'>)</span><span style='font-size:10.5pt;font-family:Monospaced'><o:p></o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced'> <u><span style='color:#AE5CB0'>plot</span></u><span style='color:#4A55DB'>(</span><span style='color:black'>t,R</span><span style='color:#5C5C5C'>*</span><span style='color:black'>u</span><span style='color:#4A55DB'>(</span><span style='color:rosybrown'>2</span><span style='color:black'>,</span><span style='color:#FFAA00'>:</span><span style='color:#4A55DB'>))</span><o:p></o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced'><o:p> </o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced'><o:p> </o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced;color:#4A55DB'>but it doesn't work.</span><span style='font-size:10.5pt;font-family:Monospaced'><o:p></o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced'><o:p> </o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced;color:#4A55DB'>Do you know why?</span><span style='font-size:10.5pt;font-family:Monospaced'><o:p></o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced'><o:p> </o:p></span></pre><pre><span style='font-size:10.5pt;font-family:Monospaced;color:#4A55DB'>Best regards.</span><span style='font-size:10.5pt;font-family:Monospaced'><o:p></o:p></span></pre></div></div></div></body></html>