GridFormat 0.4.0
I/O-Library for grid-like data structures
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GridFormat
is a header-only C++ library for reading/writing data from/to standardized grid file formats that are supported by visualization tools such as e.g. ParaView. Thus, applications that operate on grid-like data structures such as numerical simulations, GIS or computational geometry applications, can leverage GridFormat
to import/export their data from/into interoperable file formats. The typical use case for GridFormat
is within codes for numerical simulations, for visualization of results or for importing them for further processing. A variety of simulation frameworks exist, such as Dune, DuMuX, Deal.II, Fenics or MFEM, which usually provide mechanisms to export/import data produced with the framework into some file formats. However, there are situations in which one wants to use a format that the framework does not support, or, use some features of the format specification that are not implemented in the framework. GridFormat
aims to provide access to a variety of file formats through a unified interface and without the need to convert any data or to use a specific data structure to represent computational grids. Using generic programming and traits classes, GridFormat
fully operates on the user-given data structures, thereby minimizing the runtime overhead. GridFormat
also supports writing files from parallel computations that use MPI. Ideally, simulation frameworks use GridFormat
under-the-hood to avoid duplicate implementation efforts, and implement support for new formats into GridFormat
such that they are directly available to all other frameworks that utilize it.
Currently, GridFormat
is focused on VTK file formats. However, the API is suitable for any grid format describing one of the supported grid concepts. Contributions are welcomed, see below for information on how to contribute.
Prerequisites:
gcc-12/13
, clang++-16
)cmake
(tests run with cmake-3.26)It is easiest to integrate GridFormat
either as a git submodule or via the FetchContent
module of cmake
. A minimal example (using FetchContent
) of a project using GridFormat
to write a VTU file and read it back in may look like this:
Many more formats, options and functions are available, see the API documentation or have a look at the examples. Moreover, if your data is cumbersome to access via lambdas (as done in the example above), you may also provide a custom implementation of the Field
interface.
The recommended way of using GridFormat
is to include it via cmake's FetchContent
module (see quickstart). However, if you want to install GridFormat
locally into a custom location, clone the repository, enter the folder and type
Note that you can omit the explicit definition of C_COMPILER
and CXX_COMPILER
in case your default compiler is compatible. Moreover, for a system-wide installation you may omit the definition of CMAKE_INSTALL_PREFIX
. After installation, you can use cmake
to link against GridFormat
in your own project:
GridFormat
has no required dependencies, however, some features are only available if certain dependencies are present. For instance, the VTK-HDF file formats are only available if HighFive
is found, which itself requires libhdf5-dev
. If the latter is found on your system, including GridFormat
via cmake's FetchContent
(see quickstart) automatically brings in HighFive
, as it is included in GridFormat
as a git submodule. However, when installing GridFormat
from the cloned sources (as described above), make sure to use git clone --recursive
in case you want to use the HDF file formats.
The availability of some specific features of a file format may also depend on the availability of certain dependencies. For instance, compression of data (e.g. for the VTK-XML file formats) can only be used if the respective compression libraries are found on the system. Dependencies of those features are stated in the API documentation.
GridFormat
comes with a few command-line apps that you can build and install alongside the library. To include them in the build, pass the option -DGRIDFORMAT_BUILD_BINARIES=ON
to cmake
when configuring (see above). For performance reasons, you should set -DCMAKE_BUILD_TYPE=Release
when configuring. If successfully built, you can then use the command-line apps to print information on a grid file to the terminal, or convert between different file formats. For instance:
GridFormat
does not operate on a specific grid data structure, but instead, it can be made compatible with any user-defined grid types by implementing specializations for a few traits classes. For information on how to do this, please have a look at the traits classes overview, the examples, the predefined image grid implementation or the predefined traits for several frameworks.
GridFormat
comes with predefined traits for dune grid views (tested dune version: 2.9), deal.ii triangulations (tested deal.ii version: 9.6.0), cgal triangulations in 2d and 3d (tested cgal version: 5.5.2), dolfinx meshes and function spaces (tested dolfinx version: 0.6.0) and mfem meshes (tested mfem version: 4.5.2). Users of these frameworks can include these predefined traits and use GridFormat
directly (see the examples).
When reading from grid files, GridFormat
provides access to the data as specified by the file format. These specifications may not be sufficient in all applications. For instance, to fully instantiate a simulator for parallel computations, information on the grid entities shared by different processes is usually required. Since these requirements are simulator-specific, any further processing has to be done manually by the user and for their data structures. The recommended way to deal with this issue is to add any information required for reinstantiation as data fields to the output. This way, it is readily available when reading the file.
Find answered questions, ask questions or start discussions through GitHub Discussions.
Contributions are highly welcome! For bug reports, please file an issue. If you want to contribute with features, improvements or bug fixes please fork this project and open a merge request into the main branch of this repository.
In order to configure your local copy for testing, tell cmake
to include the test suite:
Afterwards, you can build and run all tests with ctest
:
Note that an internet connection is required for the call to cmake
as it pulls in ut on-the-fly. Moreover, in the configure step a Python script is invoked that produces some test data using VTK. If your Python environment does not have VTK
, this step is skipped. Note that some tests in the test suite will be skipped in this case.
To create a release, you may use the utility script util/update_versions.py
, which creates a git tag and adjusts the versions and release dates specified in the cmake setup and the CITATION.cff
file. We maintain a branch for each minor release to incorporate bug fixes and patch releases. As an example, to create a new minor release version 1.2
, you may type type the following into the console:
Afterwards, a release workflow will be triggered. If this runs through successfully, a release has been created. If not, the new tag has to be deleted and the procedure has to be repeated after fixing the errors. After a successful release, the version on main
should be increased (without triggering an actual release). Following the above example, you may run the following commands:
and pose a pull request for the changes to be incorporated in main
.
GridFormat
is licensed under the terms and conditions of the MIT License. It can be read online or in the LICENSES/MIT.txt file. See LICENSES/MIT.txt for full copying permissions.