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Re: DAE daspk solver problem

From: Sebastian Schöps
Subject: Re: DAE daspk solver problem
Date: Sat, 29 Oct 2016 06:46:23 -0700 (PDT)

Lazy_Tom wrote
> I don't think your description is correct, at the moment you are solving a
> regular ODE. The solver is not aware that the last equation doesn't
> contain the derivative of x(5). And this needs to be specified with odeset
> 'Mass' option and other parameters

Yes, you need something like
M = diag([1 1 1 1 0]);
vopt = odeset ('InitialStep', 1e-3, 'AbsTol', 1e-8,'Mass',M);
I cannot test it since I do not have a working odepkg due to Octave 4.2

Lazy_Tom wrote
> Out of curiosity, getting odest documentation (command 'doc odepkg'
> doesn't work on my windows release) and odepkg.pdf document has been a
> problem. 

Actually "doc" has also never worked for me. Not sure, if this is a bug or
an expected fail.

Lazy_Tom wrote
> The pdf is mentioned in odeset help, odepkg help and website
> ( but to the best of my
> knowledge the actual location of it doesn't exist. In fact, after
> installing the odepkg I did a search odepkg.pdf on my octave directory
> with no results. What I've found though is an odepkg.texi file which is
> indeed the package manual but it's not a pdf.

The fact that odepkg.pdf is not correctly build, is a bug of the packaging
script of odepkg. It seems the variable "TEXI2PDF = texi2pdf --clean" is not
set in the Makefile. We will fix it in the next release.

Lazy_Tom wrote
> This is how I finally found out about the 'Mass' option (yes there is a
> tiny example in odepkg_examples_dae but I don't think this is enough)

This is extensively explained in the pdf (e.g. page 14 in

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