Re: [Libmesh-users] Gradient of C1 error

[Roy S. <roy...@ic...>]

On Tue, 4 Dec 2012, Roy Stogner wrote:

> On Tue, 4 Dec 2012, Ataollah Mesgarnejad wrote:
>
>> I found a potential bug with Clough elements. I'm solving a 4th order
>> problem using C1 Clough elements and when I plot magnitude of gradient of
>> the solution I found out that it is discontinuous on mesh partition
>> boundaries. I would appreciate if any comments.
>
> Can you put together a test case reproducing the problem?

Actually, before you do that: are you sure you localized the solution
before using it to calculate the gradients?  That's the only way I
could picture encountering a partitioning-specific gradient
discontinuity in C1 elements - the gradient components aren't
calculated (and thus aren't potentially miscalculated) from some other
degrees of freedom, they *are* degrees of freedom.
---
Roy