FEMLAB toolbox implementation on Octave

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FEMLAB toolbox implementation on Octave

Mishal0488
Hi Guys

I am currently working through a book dealing with the non-linear analysis
of structures and solids.
The Author has provided some Matlab code which can be used for some of the
question within the book.

I am not that knowledgeable on how to setup the code he has provided, I hope
that someone can help...

There are 2 folder provided, includes various M files, which are essentially
the solvers for the different element types, the below initial code is given
for the path:

 % Add folder to Matlab search path
path(path,'C:\NonlinToolbox\FEMTOOLS\Drivers');

The second folder presents various M files which contain functions to
develop develop various vectors and matrices. Each function is in a
different M file.

I have attached an image for which details the setup of the "Toolbox",
however I am not accustomed with using paths and so forth.

Can someone please point me in the right direction to get started please.
Even if it is a website that gives an explication on how to perform such a
task.


<https://octave.1599824.n4.nabble.com/file/t373111/Oct.jpg>



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Re: FEMLAB toolbox implementation on Octave

nrjank
Administrator
On Fri, Jul 31, 2020 at 8:35 AM Mishal0488 <[hidden email]> wrote:

>
> Hi Guys
>
> I am currently working through a book dealing with the non-linear analysis
> of structures and solids.
> The Author has provided some Matlab code which can be used for some of the
> question within the book.
>
> I am not that knowledgeable on how to setup the code he has provided, I hope
> that someone can help...
>
> There are 2 folder provided, includes various M files, which are essentially
> the solvers for the different element types, the below initial code is given
> for the path:
>
>  % Add folder to Matlab search path
> path(path,'C:\NonlinToolbox\FEMTOOLS\Drivers');
>
> The second folder presents various M files which contain functions to
> develop develop various vectors and matrices. Each function is in a
> different M file.
>
> I have attached an image for which details the setup of the "Toolbox",
> however I am not accustomed with using paths and so forth.
>
> Can someone please point me in the right direction to get started please.
> Even if it is a website that gives an explication on how to perform such a
> task.
>


So, FEMLAB was a MATLAB toolbox, and eventually spun off to become
current, very popular finite element analysis tool Comsol
Multiphysics.  I think that transition happened around 2005, so
finding specific support for 'FEMLAB' might be difficult.

Did this textbook provide scripts to be run with FEMLAB itself (e.g.,
example model files), or did it actually provide a copy of the FEMLAB
toolbox?  It may be possible to set up a version of the old FEMLAB
toolbox to run under octave if all of the scripts are compatible, but
I have never heard of anyone doing so.


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Re: FEMLAB toolbox implementation on Octave

Mishal0488
I may be mistaken, but I do not think that the FEMLAB your are talking about
is the same as what I am. I think that they just share the same name but are
independent.

The code was developed by Dr Steen Krenk, I had to hunt down his details to
get the code, it took a few months to just get a response. I haven't seen
his name popup anywhere else other than the books he authored.

So the information which he sent me is basically all the solvers for the
different element types in a number of M files, and a number of other M
files which consist of functions that can be used to assemble various data.
The functions are easy to call up and use however I am struggling to get the
solvers running.

So essentially yes I have the "toolbox", and a number of examples.








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Re: FEMLAB toolbox implementation on Octave

nrjank
Administrator
On Fri, Jul 31, 2020 at 9:06 AM Mishal0488 <[hidden email]> wrote:

>
> I may be mistaken, but I do not think that the FEMLAB your are talking about
> is the same as what I am. I think that they just share the same name but are
> independent.
>
> The code was developed by Dr Steen Krenk, I had to hunt down his details to
> get the code, it took a few months to just get a response. I haven't seen
> his name popup anywhere else other than the books he authored.
>
> So the information which he sent me is basically all the solvers for the
> different element types in a number of M files, and a number of other M
> files which consist of functions that can be used to assemble various data.
> The functions are easy to call up and use however I am struggling to get the
> solvers running.
>
> So essentially yes I have the "toolbox", and a number of examples.

Unless there was a fork i'm not aware of, my understanding is that there's only ever been one FEMLAB.  Dr. Krenk authored some books a while back on its use, but that was the same program that was later renamed Comsol Multiphysics.  I know that Comsol released a few stripped down versions tied to textbooks that they released (example - FEMLAB ECRE Version the  book Elements of Chemical Reaction Engineering. - http://www.umich.edu/~elements/web_mod/radialeffects/femlab_ecre.pdf )

Perhaps he provided you with something similar to one of those? I'm not surprised it took him that long to dig out the code for you (but a little impressed).   In any case, I'm not aware of anyone trying to get FEMLAB m-scripts running under Octave.  If you have added everything to the path, you're going to have to try things out function by function to see what does and doesn't work. Hopefully the FEMLAB code is old enough that current Octave versions have implemented most of those functions, especially the GUI stuff, but it'll be trial and error. 

So, going back to your first email, like the instructions said you're going to need to add the FEMLAB scripts to the search path so Octave can find them. 

commands on modifying the path can be found here:

The path command they tell you to use should do the job.  (it'll add that folder to the existing search path).  then, you'll need to be in the folder with the other functions to run them. or I guess you could add that folder to the path the same way.

otherwise you'll need to give us some more specifics on what is where, what you've tried, and what isn't working.


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Re: FEMLAB toolbox implementation on Octave

Mishal0488
In reply to this post by Mishal0488
Thanks a lot.

I managed to get everything up and running.

The FEMLAB that you attached in the previous response is not the same as
what I have. The code that I have is very similar to how CALFEM works, it
just deals with non-linear analysis instead of linear static...

There is no GUI or anything, just a bunch of functions and a few solvers for
different types of analysis. Everything is tied to the authors book though,
not sure why they never provided a CD or something with all the code.

Thank you for your help, really appreciate it.



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Re: FEMLAB toolbox implementation on Octave

nrjank
Administrator
The FEMLAB that you attached in the previous response is not the same as
what I have. The code that I have is very similar to how CALFEM works, it
just deals with non-linear analysis instead of linear static...

There is no GUI or anything, just a bunch of functions and a few solvers for
different types of analysis. Everything is tied to the authors book though,
not sure why they never provided a CD or something with all the code.

could you provide the reference for the textbook you've been referring to?


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Re: FEMLAB toolbox implementation on Octave

Mishal0488
In reply to this post by Mishal0488
Krenk, S. (2009). Non-linear modeling and analysis of solids and structures.
Cambridge: Cambridge University Press.





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