Migration Guide: Transitions to io4dolfinx

Migration Guide: Transitions to io4dolfinx#

This guide outlines the necessary steps to transition your code from io4dolfinx new API introduced in io4dolfinx.

Major Changes#

The library has undergone a major refactor to support multiple IO backends. io4dolfinx now supports both ADIOS2 and h5py backends.

This allows users to choose between the high-performance, adaptable ADIOS2 framework and the standard HDF5 format via h5py.File, all using the same high-level API. It also opens the door for new backends in the future.

Key API Updates#

  1. Backend Agnosticism: You can now switch between adios2.ADIOS (default) and h5py.File by passing a backend argument.

  2. Engine Configuration: The explicit engine argument (e.g., “BP4”, “HDF5”, see ADIOS2 Engine Types) has been removed from function signatures. It is now passed via a dictionary backend_args. This is because different backends may have different engine options. For example adios2.ADIOS supports “BP4” and “HDF5”, while h5py does not use engines.

Example Transition#

Writing a Mesh#

import io4dolfinx
io4dolfinx.write_mesh("mesh.bp", mesh, engine="BP4")

import io4dolfinx
io4dolfinx.write_mesh("mesh.bp", mesh, backend="adios2", backend_args={"engine": "BP4"})

import io4dolfinx
io4dolfinx.write_mesh("mesh.bp", mesh, backend="h5py")

Writing a Function#

import io4dolfinx
io4dolfinx.write_function("solution.bp", u, time=0.0, engine="BP4")

import io4dolfinx
io4dolfinx.write_function("solution.bp", u, time=0.0, backend="adios2", backend_args={"engine": "BP4"})

import io4dolfinx
io4dolfinx.write_function("solution.bp", u, time=0.0, backend="h5py")
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