Setting a Global Default Backend

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Setting a Global Default Backend#

By default, io4dolfinx uses the adios2 backend for all read and write operations. It is possible to pass in the backend argument to individual function calls to override this default. For example the following code snippet will use the h5py backend for writing the first mesh, and use the default adios2 backend for writing the second mesh.

import dolfinx
from mpi4py import MPI
import io4dolfinx

mesh = dolfinx.mesh.create_unit_square(MPI.COMM_WORLD, 10, 10)

# Write the mesh using the h5py backend
io4dolfinx.write_mesh("first_mesh.h5", mesh, backend="h5py")
io4dolfinx.write_mesh("second_mesh.bp", mesh)  # Uses the default adios2 backend

If you want to more explicit you could also pass in the backend argument to the second write operation, i.e

io4dolfinx.write_mesh("second_mesh.bp", mesh, backend="adios2")

but it is not necessary since adios2 is the default backend.

If you prefer to use a different backend (such as h5py) across your entire application without having to pass the backend argument to every individual function call, you can configure a global default.

Usage#

Use the io4dolfinx.set_default_backend function at the start of your script to change the backend globally.

import dolfinx
from mpi4py import MPI
import io4dolfinx

# Set the global default backend to h5py
io4dolfinx.set_default_backend("h5py")

mesh = dolfinx.mesh.create_unit_square(MPI.COMM_WORLD, 10, 10)

# The following write operation will automatically use the "h5py" backend
io4dolfinx.write_mesh("my_mesh.h5", mesh)
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