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<div class="moz-cite-prefix">Hello,<br>
<br>
Le 22/04/2019 à 14:48, Richard a écrit :<br>
</div>
<blockquote
cite="mid:03fa950a-3dba-72fd-44f2-b413daaa219f@littleappletech.com"
type="cite">Hello - using scilab 6.0.2 on windows 7 pro;
<br>
I'm pretty much a newbie here, but somewhat familiar with
differential equations.
<br>
However, I cannot find a way to get a matrix (NOT a VECTOR!)
output from the scilab 'ode' function. No matter what, all it
gives is a row vector.
<br>
Example code (nonlinear Rossler equations):
<br>
<br>
function [ydot]=rdv(t,y)
<br>
ydot(1) = -(y(2) + y(3))
<br>
ydot(2) = y(1) + 0.2*y(2)
<br>
ydot(3) = 0.2 + y(3)*(y(1) - 5.7)
<br>
endfunction
<br>
t=0:0.05:50;
<br>
t0=0;y0=[-1.0,0.0,0.0];
<br>
y=ode(y0,t0,t,list(rdv,a,b,c));
<br>
param3d(y(1),y(2),y(3))
<br>
</blockquote>
<br>
<pre style="font-family:Monospaced;font-style:normal;font-size:14.0;"><span style="color:rgb(0,0,0);">y0</span> <span style="color:rgb(92,92,92);">=</span> <span style="color:rgb(74,85,219);">[</span><span style="color:rgb(92,92,92);">-</span><span style="color:rgb(188,143,143);">1.0</span><span style="color:rgb(0,0,0);">,</span><span style="color:rgb(188,143,143);">0.0</span><span style="color:rgb(0,0,0);">,</span><span style="color:rgb(188,143,143);">0.0</span><span style="color:rgb(74,85,219);">]</span><span style="color:rgb(92,92,92);">'</span><span style="color:rgb(0,0,0);">;</span>
<span style="color:rgb(0,0,0);">y</span> <span style="color:rgb(92,92,92);">=</span> <span style="color:rgb(50,185,185);">ode</span><span style="color:rgb(74,85,219);">(</span><span style="color:rgb(0,0,0);">y0</span><span style="color:rgb(0,0,0);">,</span><span style="color:rgb(0,0,0);">t0</span><span style="color:rgb(0,0,0);">,</span><span style="color:rgb(0,0,0);">t</span><span style="color:rgb(0,0,0);">,</span><span style="color:rgb(0,0,0);">rdv</span><span style="color:rgb(74,85,219);">)</span><span style="color:rgb(0,0,0);">;</span>
<span style="color:rgb(50,185,185);">param3d</span><span style="color:rgb(74,85,219);">(</span><span style="color:rgb(0,0,0);">y</span><span style="color:rgb(74,85,219);">(</span><span style="color:rgb(188,143,143);">1</span><span style="color:rgb(0,0,0);">,</span><span style="color:rgb(255,170,0);">:</span><span style="color:rgb(74,85,219);">)</span><span style="color:rgb(0,0,0);">,</span><span style="color:rgb(0,0,0);">y</span><span style="color:rgb(74,85,219);">(</span><span style="color:rgb(188,143,143);">2</span><span style="color:rgb(0,0,0);">,</span><span style="color:rgb(255,170,0);">:</span><span style="color:rgb(74,85,219);">)</span><span style="color:rgb(0,0,0);">,</span><span style="color:rgb(0,0,0);">y</span><span style="color:rgb(74,85,219);">(</span><span style="color:rgb(188,143,143);">3</span><span style="color:rgb(0,0,0);">,</span><span style="color:rgb(255,170,0);">:</span><span style="color:rgb(74,85,219);">)</span><span style="color:rgb(74,85,219);">)
<font color="#000000">works:</font>
<img src="cid:part1.0C3606B7.5755FD26@free.fr" alt="" height="267" width="329">
<font color="#000000">But the fact that y and t must be of "orthogonal shapes" is not clearly indicated
or highlighted in the ode() help page. This clearly misses.
There are some (rather unclear) explanation for y being even a matrix !
but for simpler multivariable cases, nothing.
We should improve the page.
</font></span></pre>Anyway, writting param3d(y(1),y(2),y(3))
plots only one point.
HTH
Samuel
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