On Wed, 1 Oct 2008, John Peterson wrote:
> Static may not even be required. I think a single system with 3
> different matrix assembly "branches" is what you want.
John is probably exactly right. In the worst case, if one of your
systems has a constant matrix, having to reassemble it over and over
again will waste a few CPU cycles... but even then it may be worth it
to save the memory cost of the entire matrix.
> for (qp)
> for (i)
> for (j)
> switch (system_num) // A variable you define to order the 3 systems
> case 1:
> K(i,j) += something; break;
> case 2:
> K(i,j) += something else; break;
> end switch
> end j
> end i
> end qp
I think putting the switch statement outside the for loops is slightly
more efficient, if matrix assembly time ever becomes a noticeable
issue (as it did for one app of mine).
> I've done this in the past to assemble different right-hand side
> vectors depending on whether I was solving the main system or an
> auxiliary arclength continuation system of equations. It should be
> straightforward to extend that to the matrix assembly itself as in the
> pseudocode above.
It is straightforward, and I have no excuse for not thinking of it
and mentioning it myself. From my first shear thinning flow code:
void assemble_stokes (EquationSystems& es,
const std::string& system_name)
{
if (find_vorticity)
{
assemble_vorticity(es, system_name);
return;
}
assemble_stokes() built the residual and jacobian of the Navier-Stokes
system to solve; assemble_vorticity built a linear system to project
the vorticity into the same smooth space for plotting.
---
Roy
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