<html>
<head>
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
</head>
<body>
<p>Hello,</p>
<p>I can tell you what happened: for some values of lambda and some
values of K(4,5,6), your function is undefined and the leastsq
goes kaboom!</p>
<p>It is never a good idea to fit a function that can become
undefined for some parameters/xvalues.<br>
Try to redefine the function you fit to avoid any undefined
values.</p>
<p>Antoine<br>
</p>
<p>I was able to use the range [1:51], but not [1:52].<br>
</p>
<div class="moz-cite-prefix">Le 27/08/2020 à 16:52, Dang Ngoc Chan,
Christophe a écrit :<br>
</div>
<blockquote type="cite"
cite="mid:AM0PR07MB393746021EE81DE351843C74E5550@AM0PR07MB3937.eurprd07.prod.outlook.com">
<pre class="moz-quote-pre" wrap="">Hello all,
Let's talk about optics.
I have a glass, its refraction index n varies with the wavelength lamba.
I have a CSV file with the corresponding data (verre_HOQ.cvs attached), 52 points.
I want to model this with the Sellmeier model
<a class="moz-txt-link-freetext" href="https://en.wikipedia.org/wiki/Sellmeier_equation">https://en.wikipedia.org/wiki/Sellmeier_equation</a>
and use for this the attached script (regression_sellmeier.sce).
Mind to set the path at line 7 of the script if you want to run it.
My problem:
I can run piecewise regression,
i.e. it runs when I work with the points 1 to 25, 13 to 39, or 32 to 52;
e.g. at lines 11 and 12, it works when I use
// ----------
lambda = 1e-3*donnees(1:25, 1); // en µm
nexp = donnees(1:25, 2);
// ----------
but when I try to extend these ranges (and of course when I try to use all the points),
it fails with the following error:
5215700pt: Wrong type for output argument #1: Real scalar expected.
Can anyone tell me what goes on here?
Regards
--
Christophe Dang Ngoc Chan
Mechanical calculation engineer
General
This e-mail may contain confidential and/or privileged information. If you are not the intended recipient (or have received this e-mail in error), please notify the sender immediately and destroy this e-mail. Any unauthorized copying, disclosure or distribution of the material in this e-mail is strictly forbidden.
</pre>
<br>
<fieldset class="mimeAttachmentHeader"></fieldset>
<pre class="moz-quote-pre" wrap="">_______________________________________________
users mailing list
<a class="moz-txt-link-abbreviated" href="mailto:users@lists.scilab.org">users@lists.scilab.org</a>
<a class="moz-txt-link-freetext" href="http://lists.scilab.org/mailman/listinfo/users">http://lists.scilab.org/mailman/listinfo/users</a>
</pre>
</blockquote>
</body>
</html>