<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META content="text/html; charset=us-ascii" http-equiv=Content-Type>
<META name=GENERATOR content="MSHTML 8.00.6001.18999"></HEAD>
<BODY>
<DIV><FONT size=2 face=Arial>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><FONT size=3><FONT
face="Times New Roman">Dear All,<?xml:namespace prefix = o ns =
"urn:schemas-microsoft-com:office:office" /><o:p></o:p></FONT></FONT></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><o:p><FONT size=3
face="Times New Roman"> </FONT></o:p></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><FONT size=3><FONT
face="Times New Roman">For some times I’m testing Scilab macros for optimization
purposes ; “optimization” has to be intended here as an inverse method for
fitting parameters (i.e. so that finite element analysis fit test
measurements).<o:p></o:p></FONT></FONT></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><o:p><FONT size=3
face="Times New Roman"> </FONT></o:p></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><FONT size=3><FONT
face="Times New Roman">I tested basic macros such as fminsearch for unbounded
fitting as well as Nelder-Mead one for bracketed parameters fitting. Basically
the “cost function” is the normalized Sum of the Square errors SSE from the FEA
to the measurements.<o:p></o:p></FONT></FONT></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><o:p><FONT size=3
face="Times New Roman"> </FONT></o:p></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><FONT face="Times New Roman"><FONT
size=3>In my FEA<SPAN class=516203511-25012011>'s</SPAN> <SPAN
class=516203511-25012011>the </SPAN><SPAN class=516203511-25012011>variables
</SPAN>can be material parameters, spring stiffness’s, damping ratio and so on :
the simplex method is well adapted since the former <SPAN
class=516203511-25012011>variables </SPAN>are not analytically described in the
cost function and since it’s not necessary to calculate the gradient vector nor
the Hessian matrix …<o:p></o:p></FONT></FONT></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><o:p><FONT size=3
face="Times New Roman"> </FONT></o:p></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><o:p></o:p></SPAN> </P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><FONT size=3><FONT
face="Times New Roman">If this method is robust nevertheless it remains rather
slow !<o:p></o:p></FONT></FONT></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><o:p><FONT size=3
face="Times New Roman"> </FONT></o:p></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><o:p><FONT size=3
face="Times New Roman"> </FONT></o:p></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><FONT size=3><FONT
face="Times New Roman">Is there a way or another macro I can use to reduce the
number of loops and the time consuming consequently
?<o:p></o:p></FONT></FONT></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><o:p><FONT size=3
face="Times New Roman"> </FONT></o:p></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><FONT
face="Times New Roman"><FONT size=3><I style="mso-bidi-font-style: normal"><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><U>Nota</U></SPAN></I><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB> : I was thinking in OPTIM macro but
from my understanding the cost function need to be twice differentiable at
least <SPAN class=516203511-25012011> </SPAN>(for the <SPAN
class=516203511-25012011>G</SPAN>radient and the Hessian ) i.e. analytically
link to the parameters … isn’t it ?<o:p></o:p></SPAN></FONT></FONT></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><o:p><FONT size=3
face="Times New Roman"> </FONT></o:p></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><FONT size=3><FONT
face="Times New Roman">Thanks in advance for any advice (for a better
understanding)<o:p></o:p></FONT></FONT></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><o:p><FONT size=3
face="Times New Roman"> </FONT></o:p></SPAN></P>
<P style="MARGIN: 0cm 0cm 0pt" class=MsoNormal><SPAN
style="mso-ansi-language: EN-GB" lang=EN-GB><FONT size=3><FONT
face="Times New Roman">Paul<o:p></o:p></FONT></FONT></SPAN></P></FONT></DIV>
<DIV> </DIV></BODY></HTML>
<pre>--------------------------------------------------------------------------------
Le présent mail et ses pièces jointes sont confidentiels et destinés à la personne ou aux personnes visée(s) ci-dessus. Si vous avez reçu cet e-mail par erreur, veuillez contacter immédiatement l'expéditeur et effacer le message de votre système. Toute divulgation, copie ou distribution de cet e-mail est strictement interdite.
This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error, please contact the sender and delete the email from your system. If you are not the named addressee you should not disseminate, distribute or copy this email.