[dune-functions] [Dune-functions-commit] [Commit] dune-functions - e7abafb: Add protocol for Aachen meeting

Carsten Gräser graeser at mi.fu-berlin.de
Tue Mar 25 21:54:37 CET 2014

Hi Steffen,
didn't we decide that the global multi
indices should always be consecutive?
If not, we may also add a method to
check if a prefix does appear in any


On 25. März 2014 19:19:23 MEZ, "Steffen Müthing" <muething at dune-project.org> wrote:
>New commit, appeared at Tue Mar 25 19:19:23 2014 +0100
>as part of the following ref changes:
>    branch refs/heads/master    updated from 3289b50 -> e7abafb
>Browsable version:
>commit e7abafbf4a2892734c598c4984a633d4709a1cc2
>Author: Steffen Müthing <muething at dune-project.org>
>Date:   Tue Mar 25 19:18:10 2014 +0100
>    Add protocol for Aachen meeting
>doc/protocol_achen_2014.txt | 57
> 1 file changed, 57 insertions(+)
> create mode 100644 doc/protocol_achen_2014.txt
>diff --git a/doc/protocol_achen_2014.txt b/doc/protocol_achen_2014.txt
>new file mode 100644
>index 0000000..403061c
>--- /dev/null
>+++ b/doc/protocol_achen_2014.txt
>@@ -0,0 +1,57 @@
>+Function Space Bases
>+- for now only depending on GridView (maybe also for Grids or other
>entity sets - tbd)
>+- Global interface minimalistic (only provide enoug information for
>computing container sizes)
>+- main interface through a LocalView obtained from the global basis
>+- Prototype implementation for PQ1 and flat global index in
>+- LocalView returned by value (can have multiple views at the same
>+- View can be bound to and unbound from elements and provides access
>to a bound element
>+- Concrete interaction with a bound view through a nested tree object
>(name tbd)
>+LocalView Tree
>+- Tree represents an element-local tensor product space
>+- Leaves correspond to a local finite elements from
>+- Tree is implemented using dune-typetree
>+- leafs can map leaf-local consecutive indices for shape functions to
>+  - a unique index with respect to the entire local basis tree, which
>is consecutive and 0-based
>+  - a globally unique (for the entire function space) multi-index. The
>exact semantics and
>+    properties of this multi-index are not defined yet. There may be
>multiple classes of multi-indices
>+    with different properties and complexities.
>+    A very simple index would be of length 1 and consecutive. In
>general, indices can be of varying
>+    length and can contain non-consecutive entries (e.g. for the
>+    At a later stage, those classes will need to be precisely defined
>to create an interface to container
>+    backends that will depend on the exact semantics of those classes.
>+  - There are interfaces to obtain either a single global index or to
>efficiently populate a container with
>+    all global indices for the currently bound grid element
>+Smaller Changes
>+- GridViewFunction was revised to work with new
>+- Replace FunctionHandle for derived functions with shared_ptr
>+- Functions now longer inherit from enable_shared_from_this
>+- Convenience interfaces by Carsten to convert to / from callables
>(via std::function)
>+Open Questions
>+- Container backends
>+- Index transformations (for systems / blocking / etc.)
>+- Avoid interface restrictions wr.t. features like automatic backend
>construction (PDELab) or additional
>+  information like local sparsity structures (Carsten)
>+- Semantics and properties of canonical multi-index classes
>+- Constraints
>+- higher-order derivatives of shape functions for non-affine geometry
>+- dune-localfunctions: Several smaller issues
>+- revise global valued interface of dune-localfunctions
>+Oli: port additional bases (P^k) from dune-fufem
>+Christian: functions interface for PDELab
>+Christian / Steffen: discuss minimum backend interface from PDELab
>point of view
>Dune-functions-commit mailing list
>Dune-functions-commit at dune-project.org

Prof. Dr. Carsten Gräser
Freie Universität Berlin
Institut für Mathematik
Arnimallee 6
14195 Berlin, Germany
phone: +49 30 838 75349
fax  : +49 30 838 54977
email: graeser at mi.fu-berlin.de
URL  : http://page.mi.fu-berlin.de/graeser

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