On 4/16/19 12:15 PM, Robert Spartus wrote:
>
> Thanks a ton for your input! You are completely right. Now that is you
> mention it, the problem is completely obvious.
>
> I really appreciate you pulling me out of that hole.
You're welcome. I'm glad it helped!
Best
W.
--
Dear Wolfgang.
Thanks a ton for your input! You are completely right. Now that is you
mention it, the problem is completely obvious.
I really appreciate you pulling me out of that hole.
Bests,
Bob
On Tue, 16 Apr 2019 at 15:49, Wolfgang Bangerth
wrote:
> On 4/15/19 8:46 AM, Robert Spartus
On 4/15/19 8:46 AM, Robert Spartus wrote:
>
> > It is hard to imagine situations in which the mass matrix would be
> singular.
> > It is a positive definite form that gives rise to the mass matrix and so it
> > really shouldn't be singular at all. Can you show the code again with which
> >
Dear Wolfgang,
> It is hard to imagine situations in which the mass matrix would be
singular.
> It is a positive definite form that gives rise to the mass matrix and so
it
> really shouldn't be singular at all. Can you show the code again with
which
> you build it?
It seems that my mesh is
On 4/14/19 11:59 PM, Robert Spartus wrote:
>
> Thanks for the insightful discussion on the integrating issue. Wolfgang, I
> guess your last argument is the same as you gave in one of your fantastic
> lectures?
Yes. (Also, thanks for the compliment :-) )
> Incidentally, do you have any ideas
Dear all,
Thanks for the insightful discussion on the integrating issue. Wolfgang, I
guess your last argument is the same as you gave in one of your fantastic
lectures?
Incidentally, do you have any ideas on how to solve the singularity of the
mass matrix in this vector-valued problem?
Bests,
On 4/12/19 1:55 PM, luca.heltai wrote:
> Wolfgang, is that true also for mass matrices? I’d agree with you for
> stiffness matrices, but I’d surprised this worked ok for mass
> matrices as well.
I'm pretty sure. The theory goes like this: instead of computing the
matrix and rhs using the
Wolfgang, is that true also for mass matrices? I’d agree with you for stiffness
matrices, but I’d surprised this worked ok for mass matrices as well.
If so, I’ve always been over integrating in my life…
:)
L.
> On 12 Apr 2019, at 21:15, Wolfgang Bangerth wrote:
>
> On 4/12/19 8:41 AM,
On 4/12/19 8:41 AM, Robert Spartus wrote:
>
> That is some fascinating information! It seems like step-44, for
> instance, does not follow this recommendation, as there the polynomial
> degree is 2, while the quadrature degree is 3
Actually, Gauss quadrature with degree+1 points in each
Dear Luca,
That is some fascinating information! It seems like step-44, for instance,
does not follow this recommendation, as there the polynomial degree is 2,
while the quadrature degree is 3, instead of the recommended 5 (
If you plan to use any domain that is not a square (or an affine
transformation), you have to make sure you integrate exactly the product of two
polynomials of order degree and of the determinant of the Jacobian. This last
term is constant only for simple meshes, but it is the square root of a
Dear Luca,
Thanks for your suggestion. Unfortunately, it did not solve the problem. I
am sending the modified version, as well as the output of the program.
Out of curiosity, what is the reason to use (2*fe_degree + 1)? Checking
step-8, I notice that there a quadrature degree one larger than the
You are integrating using two quadrature points per direction. Can you raise
that to (2*fe.degree+1)?
L.
> On 11 Apr 2019, at 10:58, bobspar...@gmail.com wrote:
>
> Dear all,
>
> First of all, thanks for the awesome library. I am starting to learn deal.II,
> and it is great! The
Dear all,
First of all, thanks for the awesome library. I am starting to learn
deal.II, and it is great! The documentation has been extremely helpful so
far.
I am trying to solve the time dependent elastic equation, and there we
naturally have a mass matrix-like for the velocities. To build
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