Hi Jordi,
I took that course last year, and also had some troubles with the first coding
assignment. As Curro mentioned, there was an update to deal.ii after the course
was created that could affect the results for the 3rd order solution. It had
to do with a change in spacing of the quadrature points from equidistant to
Gauss-Lobatto for orders > 2. If you're also having trouble with the 2nd order
problem, that would suggest you have another issue to sort out (looks like
Jean-Paul gave you some feedback to help), but I wanted to point you to this
thread deeper within the Coursera forums that helped me out in the end, as I
was using a later release of deal.ii: Coursera Forum Link - Programming
Assignment: Coding Assignment 1 .
The first assignment was by far the most difficult & time consuming, the
remaining ones got easier each time. I thought it was a great course and
learned a lot!
Good Luck!Brandon
On Monday, December 30, 2019, 3:31:18 AM MST, Curro Trigo
<[email protected]> wrote:
Hello Jordi:
I also joined "TheFinite Element Method for problems in physics" in Coursera
and I had similar problems. I worked them around by switching back to version
8.2.1 of deal.II library.With version 8.5.0, the latest available at that time,
it did not work fine. Idon’t know the root cause.
I alsothink there is a mentoring problem with this particular course; a new
videoshould have been posted to clarify the changes required to make the
assignmentwork with the current versions of deal.II.
NeverthelessI still think "The Finite Element Method for problems in physics"
inCoursera is highly recommendable.
Best wishesfor 2020.
Curro Trigo
On Sunday, December 29, 2019 at 10:29:11 PM UTC+1, Jean-Paul Pelteret wrote:
Dear Jordi,
Firstly, welcome to the forum. Well, as this is a course assignment I think
that its fair to assume that some course mentor should be available to guide
you toward the solution to the problem. You say that you’ve had no luck on the
course site forum — that’s a bit poor. Anyway, I wouldn’t want to give away the
answer, but after skimming through your code and seeing your comment that
I checked my basis functions and its gradients and seem to be correct
I would say that you’re looking in the right sorts of places for the problem.
Remember that in the finite element method we use basis functions to
approximate the solution, and these need to evaluated in certain places where
we form approximations for certain calculations. You’ve seem to have the
“evaluated” part sorted, but what about the other part? What might need to
change when you move from linear to higher order shape functions in order to
ensure that those approximate calculations are performed accurately?
I hope that my somewhat cryptic response will give you a nudge in the right
direction. Oh, and I also hope that you take a look at our tutorial programs
sometime to see how we typically code up FEM problems. It’s good to get a hand
on the basics, but you might be pleased to know that the deal.II library does
most of this for you in a clean and easy to understand manner.
Best,Jean-Paul
On 28 Dec 2019, at 02:01, Jordi Parra Porcar <[email protected]> wrote:
Dear all,
I am new to this group. I wanted to ask for some help as I am unable to find
the solution to a problem.I am following a course in Coursera called "The
Finite Element Method for problems in physics". The course first assignment it
is about coding with dealii.I have posted in the Coursera forum but got no
answer so, I am trying by here just to see if I am lucky and someone give me a
hand.The issue that I have is that I can only solve the problem with 1st order
basis functions as with quadratic and cubic basis functions it gives me an
error related with the K global matrix.I have been going around discussions but
still unable to find where is the problem. I checked my basis functions and its
gradients and seem to be correct.I uploaded all the files related to the
problem. Now the ./main executes the problem=1 with order=1, that is the linear
basis function.
Thank you all in advance and happy ending of the year!
Jordi,
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<CMakeCache.txt><CMakeLists. txt><FEM1.h><Makefile><cmake_
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