dolfin team mailing list archive

["Marie E. Rognes" <meg@xxxxxxxxx>]

On 03/03/2011 08:03 PM, Johan Hake wrote:
> Hello!
>
> I am using Mixed spaces with Reals quite alot. It turnes out that assemble
> forms with functions from MixedFunctionSpaces containing Real spaces are dead
> slow. The time spent also increase with the number of included Real spaces,
> even if none of them are included in form which is assembled.
>
> The attached test script illustrates this.

By replacing "CG", 1 by "R", 0 or?

> The test script also reviels that an unproportial time is spent in FFC
> generating the code. This time also increase with the number of Real spaces
> included. Turning of FErari helped a bit with this point.

I can take a look on the FFC side, but not today.

--
Marie

> I have not profiled any of this, but I just throw it out there. I do not
> recognize any difference between for example Epetra or PETSc backend as
> suggested in the fixed bug for building of sparsity pattern with global dofs.
>
> My test has been done on a DOLFIN 0.9.9+. I haven't profiled it yet.
>
> Output from summary:
>
>    Tensor without Mixed space  |       0.11401     0.11401     1
>    With 1 global dofs          |       0.40725     0.40725     1
>    With 2 global dofs          |       0.94694     0.94694     1
>    With 4 global dofs          |         2.763       2.763     1
>    With 8 global dofs          |        9.6149      9.6149     1
>
> Also the amount of memory used to build the sparsity patter seams to double
> for each step. The memory print for a 32x32x32 unit cube with 16 global dofs
> was 1.6 GB memory(!?).
>
> Johan
>
>
>
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