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<p><font size="2" face="sans-serif">Hi Paul,</font><br>
<br>
<font size="2" face="sans-serif">I have a suggestion but also a more general observation.</font><br>
<br>
<font size="2" face="sans-serif">I have also been solving simultaneous linear equations of the form A * x = b. My first thought was to use the method:</font><br>
<br>
<font size="2" face="sans-serif"> x = A \ b</font><br>
<br>
<font size="2" face="sans-serif">and it seemed to me that if Tunji's equations are well-behaved then this may be the easiest method, rather than using 'linsolve'.</font><br>
<br>
<font size="2" face="sans-serif">In my case I'm trying to solve electrical circuit equations which are sparse and include complex values. I used x = A \ b to begin with but for some component values I get messages like:<br>
</font><br>
<font size="2" face="sans-serif"> Warning :</font><br>
<font size="2" face="sans-serif"> matrix is close to singular or badly scaled. rcond = 1.0388D-08</font><br>
<font size="2" face="sans-serif"> computing least squares solution. (see lsq).</font><br>
<br>
<font size="2" face="sans-serif">The method goes to completion but the results are obviously wrong.</font><br>
<font size="2" face="sans-serif">If I use 'linsolve' instead, it goes to completion without producing any warnings or errors but the results are wrong.</font><br>
<font size="2" face="sans-serif">For me, 'umfpack' is the best method by far and works very well.</font><br>
<br>
<font size="2" face="sans-serif">This is a situation which has occurred several times before. SciLab is a very powerful piece of software and as a result there may (apparently) be several methods of doing the same thing but there are rarely explanations of how each method works or why you would use one method rather than another.</font><br>
<br>
<font size="2" face="sans-serif">Best wishes,</font><br>
<br>
<font size="2" face="sans-serif">Adrian.</font><br>
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<ul style="padding-left: 1pt"><font size="2" color="#333333" face="Arial"><b>Adrian Weeks </b></font><font size="1" color="#666666" face="Arial"><br>
Development Engineer <br>
<br>
<br>
HID Global,<br>
3 Cae Gwyrdd,<br>
Green Meadow Springs<br>
Business Park,<br>
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United Kingdom.<br>
+44 (0)29 20528523 (Office)</font><font size="1" color="#0000FF" face="Arial"><u><br>
</u></font><a href="mailto:aweeks@hidglobal.com"><font size="1" color="#0000FF" face="Arial"><u>aweeks@hidglobal.com</u></font></a><font size="1" color="#0000FF" face="Arial"><u><br>
</u></font><a href="http://www.hidglobal.com/"><font size="1" color="#0000FF" face="Arial"><u>www.hidglobal.com</u></font></a></ul>
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<ul style="padding-left: 1pt"><a href="http://www.hidglobal.com/"><img src="cid:1__=0FBBF633DFA16AB98f9e8a93df93869@prox.com" width="130" height="170" border="0"></a></ul>
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<img width="16" height="16" src="cid:2__=0FBBF633DFA16AB98f9e8a93df93869@prox.com" border="0" alt="Inactive hide details for Paul Bignier ---18/03/2014 10:01:09---Hi Tunji, linsolve help page"><font size="2" color="#424282" face="sans-serif">Paul Bignier ---18/03/2014 10:01:09---Hi Tunji, linsolve help page</font><br>
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<ul style="padding-left: 4pt"><font size="1" color="#5F5F5F" face="sans-serif">From:</font></ul>
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<font size="1" face="sans-serif">Paul Bignier <paul.bignier@scilab-enterprises.com></font></td></tr>
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<ul style="padding-left: 4pt"><font size="1" color="#5F5F5F" face="sans-serif">To:</font></ul>
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<font size="1" face="sans-serif">"International users mailing list for Scilab." <users@lists.scilab.org>, iootunniyi@futa.edu.ng</font></td></tr>
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<ul style="padding-left: 4pt"><font size="1" color="#5F5F5F" face="sans-serif">Date:</font></ul>
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<font size="1" face="sans-serif">18/03/2014 10:01</font></td></tr>
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<ul style="padding-left: 4pt"><font size="1" color="#5F5F5F" face="sans-serif">Subject:</font></ul>
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<font size="1" face="sans-serif">Re: [Scilab-users] Solving linear simultaneous equations</font></td></tr>
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<ul style="padding-left: 4pt"><font size="1" color="#5F5F5F" face="sans-serif">Sent by:</font></ul>
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<font size="1" face="sans-serif">"users" <users-bounces@lists.scilab.org></font></td></tr>
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Hi Tunji,<br>
<br>
linsolve </font><a href="http://help.scilab.org/docs/5.4.1/en_US/linsolve.html"><font size="3" color="#0000FF" face="serif"><u>help page</u></font></a><font size="3" face="serif"> contains utilization examples.<br>
<br>
If you still cannot use it, please tell us more about the problem you are trying to solve.<br>
<br>
Regards,<br>
Paul<br>
<br>
</font><br>
<font size="3" face="serif">On 03/18/2014 10:16 AM, 'Tunji OTUNNIYI wrote:</font>
<ul style="padding-left: 36pt"><font size="2" color="#1F497D" face="Calibri">Hello:</font><br>
<font size="2" face="Calibri"> </font><br>
<font size="2" face="Calibri">I am quite a starter here.</font><br>
<font size="2" color="#1F497D" face="Calibri"> </font><br>
<font size="2" face="Calibri">Could someone please help me through solving n x n linear simultaneous equations.</font><br>
<font size="2" face="Calibri">I saw linsolve in help, but can’t follow through</font><font size="2" color="#1F497D" face="Calibri"> </font><font size="2" face="Calibri">the arguments. Applying the calling sequence to a simple example will be of help.</font><br>
<font size="2" face="Calibri">Thanks a lot.</font><br>
<font size="2" face="Calibri"> </font><br>
<font size="2" face="Calibri">Tunji OTUNNIYI | MME SEET FUTA Akure, Nigeria.</font><br>
<font size="2" face="Calibri"> </font>
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<tt><font size="3">-- <br>
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