Add new legacy bound (#53)

* Add new legacy bound

* More updates to readme

* Bump citation file

CITATION.cff

@@ -5,5 +5,5 @@ authors:
   given-names: "Jørgen S."
   orcid: "0000-0001-6489-8858"
 title: "ADIOS2Wrappers"
-version: "0.7.1"
-date-released: 2023-10-15
+version: "0.7.2"
+date-released: "2023-02-07"

README.md

@@ -5,37 +5,36 @@
 
 This is an extension for [DOLFINx](https://github.com/FEniCS/dolfinx/) to checkpoint meshes, meshtags and functions using [ADIOS2](https://adios2.readthedocs.io/en/latest/).
 
-## Docker
+The code uses the adios2 Python-wrappers to write DOLFINx objects to file, supporting N-to-M (*recoverable*) and N-to-N (*snapshot*) checkpointing.
+See: [Checkpointing in DOLFINx - FEniCS 23](https://jsdokken.com/checkpointing-presentation/#/) for more information.
+
+For scalability, the code uses [MPI Neighbourhood collectives](https://www.mpi-forum.org/docs/mpi-3.1/mpi31-report/node200.htm) for communication across processes.
+
+## Installation
+
+### Docker
 ADIOS2 is installed in the official DOLFINx containers.
 ```bash
 docker run -ti -v $(pwd):/root/shared -w /root/shared --name=dolfinx-checkpoint ghcr.io/fenics/dolfinx/dolfinx:nightly
 ```
 
-## Conda
-To use with conda (DOLFINx release v0.7.0 works with v0.7.1 of ADIOS4DOLFINx)
+### Conda
+To use with conda (DOLFINx release v0.7.0 works with v0.7.2 of ADIOS4DOLFINx)
 ```bash
 conda create -n dolfinx-checkpoint python=3.10
 conda activate dolfinx-checkpoint
 conda install -c conda-forge fenics-dolfinx pip adios2
-python3 -m pip install git+https://github.com/jorgensd/[email protected].1
+python3 -m pip install git+https://github.com/jorgensd/[email protected].2
 ```
 
-# Long term plan
-The long term plan is to get this library merged into DOLFINx (rewritten in C++ with appropriate Python-bindings).
-_________________
-
-# Functionality 
+## Functionality 
 
-## Implementation details
-The code uses the adios2 Python-wrappers to write DOLFINx objects to file, supporting N-to-M (*recoverable*) and N-to-N (*snapshot*) checkpointing.
-See: [Checkpointing in DOLFINx - FEniCS 23](https://jsdokken.com/checkpointing-presentation/#/) for more information.
 
-For scalability, the code uses [MPI Neighbourhood collectives](https://www.mpi-forum.org/docs/mpi-3.1/mpi31-report/node200.htm) for communication across processes.
 
-## DOLFINx
+### DOLFINx
 - Reading and writing meshes, using `adios4dolfinx.read/write_mesh`
 - Reading and writing meshtags associated to meshes `adios4dolfinx.read/write_meshtags`
-- Reading checkpoints for any element (serial and parallel, one checkpoint per file). Use `adios4dolfinx.read/write_function`.
+- Reading checkpoints for any element (serial and parallel, arbitrary number of functions and timesteps per file). Use `adios4dolfinx.read/write_function`.
 
 > [!IMPORTANT]  
 > For a checkpoint to be valid, you first have to store the mesh with `write_mesh`, then use `write_function` to append to the checkpoint file.
@@ -46,15 +45,20 @@ For scalability, the code uses [MPI Neighbourhood collectives](https://www.mpi-f
 > [!IMPORTANT]  
 > Only one mesh per file is allowed
 
+
+### Backwards compatibility
 > [!WARNING]
-> If you are using checkpoints written with `adios4dolfinx` prior to time-dependent/multi-function support, please use the `legacy=True` flag for reading in the checkpoint
+> If you are using checkpoints written with `adios4dolfinx<0.7.2` please use the `legacy=True` flag for reading in the checkpoint with
+> with any newer version
 
 
-## Legacy DOLFIN
+### Legacy DOLFIN
 Only checkpoints for `Lagrange` or `DG` functions are supported from legacy DOLFIN
 - Reading meshes from the DOLFIN HDF5File-format
 - Reading checkpoints from the DOLFIN HDF5File-format (one checkpoint per file only)
 - Reading checkpoints from the DOLFIN XDMFFile-format (one checkpoint per file only, and only uses the `.h5` file)
 
 See the [API](./docs/api) for more information.
-_________________
+
+## Long term plan
+The long term plan is to get this library merged into DOLFINx (rewritten in C++ with appropriate Python-bindings).

tests/create_legacy_checkpoint.py

@@ -19,7 +19,7 @@
 from importlib.metadata import version
 
 a4d_version = version("adios4dolfinx")
-assert a4d_version < "0.8.0", f"Creating a legacy checkpoint requires adios4dolfinx < 0.8.0, you have {a4d_version}."
+assert a4d_version < "0.7.2", f"Creating a legacy checkpoint requires adios4dolfinx < 0.7.2, you have {a4d_version}."
 
 
 def f(x):