Sorry, please disregard that code. I meant to put fxy to be the exact
solution at particular qp's. However, I realized that it's not defined
except at Nodes. I really don't know how to do this...

Thanks for your help in advance,
Karen


On Thu, Mar 25, 2010 at 5:50 PM, Karen Lee <[email protected]> wrote:

> Dear all,
>
> I'm trying to store data from _node_data associated with a Mesh on a degree
> 1 LAGRANGE basis in the code in order for this _node_data (supposed to be a
> smooth function) to be used in the rhs of my Poisson problem.
>
>>
>> Add a second system, an ExplicitSystem, to your EquationSystems.  Add
>> a single variable to it.  Load data as a solution into that, and query
>> it when you're integrating your real system.
>
>
>  Does it mean I just do something very similar to example 3 (poisson
> problem) and use my _node_data as the "exact_solution"? I'm not quite sure
> how to set up the problem though... I'm guessing I'm doing a linear
> interpolation of my data... In that case, do I just do the following?
> (Sorry, I need things spelled out more since I'm getting confused with the
> data structures.)
>
> for (unsigned int qp=0; qp<qrule.n_points(); qp++)
>         {
>
>           for (unsigned int i=0; i<phi.size(); i++)
>             for (unsigned int j=0; j<phi.size(); j++)
>               {
>                 Ke(i,j) += JxW[qp]*(phi[i][qp]*phi[j][qp]);
>               }
>
>           {
>             //const Real x =
> q_point[qp](0);
>             //const Real y =
> q_point[qp](1);
>             //const Real eps =
> 1.e-3;
>
>             const Real fxy = 1;
>             for (unsigned int i=0; i<phi.size(); i++)
>               Fe(i) += JxW[qp]*fxy*phi[i][qp];
>           }
>         }
>
> I tried to assign _node_data directy to _variables, but I guess a Variable
> is not supposed to hold any value except to design what the name, ID and FE
> type is for the solution of a problem? Please clarify...
>
>
> Also, since I don't have the analytic form of my _node_data. When I define
> it will it just become a bunch of if/then statements? (checking for xyz
> values and then assigning the appropriate data value...)
>
> Thanks,
> Karen
>
>
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