Export

When the problem is solved, and the solution vector u is known we typically want to visualize it. The simplest way to do this is to write the solution to a VTK-file, which can be viewed in e.g. Paraview. To write VTK-files, Ferrite comes with an export interface with a WriteVTK.jl backend to simplify the exporting.

The following structure can be used to write various output to a vtk-file:

VTKGridFile("my_solution", grid) do vtk    write_solution(vtk, dh, u)end;

VTKGridFile for the closed file "my_solution.vtu".

where write_solution is just one example of the following functions that can be used

Instead of using the do-block, it is also possible to do

vtk = VTKGridFile("my_solution", grid)write_solution(vtk, dh, u)# etc.close(vtk);

VTKGridFile for the closed file "my_solution.vtu".

The data written by write_solution, write_cell_data, write_node_data, and write_projection may be either scalar (Vector{<:Number}) or tensor (Vector{<:AbstractTensor}) data.

For simulations with multiple time steps there are two options.

Time series with VTKHDF (recommended)

A VTKHDFGridFile — the HDF5-based VTKHDF format — can hold a whole time series in a single file, with the grid stored only once, no matter how many steps are saved. This requires VTKHDF.jl to be loaded. Open the file with temporal = true and write each step with write_timestep:

using VTKHDFvtkhdf = VTKHDFGridFile("my_results.vtkhdf", dh; temporal = true)for t in range(0, 1, 5)    # Do calculations to update u    write_timestep(vtkhdf, t) do vtk        write_solution(vtk, dh, u)    endendclose(vtkhdf);

The same data functions as above are supported. See Transient heat equation for an example.

Time series with a Paraview collection (`.pvd`)

Alternatively, with the XML-based formats one VTK (.vtu) file is written for each time step. To connect the actual time with each of these files, the paraview_collection function from WriteVTK.jl can be used. This creates one paraview datafile (.pvd) and one VTKGridFile (.vtu) for each time step.

using WriteVTKpvd = paraview_collection("my_results")for (step, t) in enumerate(range(0, 1, 5))    # Do calculations to update u    VTKGridFile("my_results_$step", dh) do vtk        write_solution(vtk, dh, u)        pvd[t] = vtk    endendvtk_save(pvd);

6-element Vector{String}:
 "my_results.pvd"
 "my_results_1.vtu"
 "my_results_2.vtu"
 "my_results_3.vtu"
 "my_results_4.vtu"
 "my_results_5.vtu"

Export

Time series with VTKHDF (recommended)

Time series with a Paraview collection (.pvd)

Time series with a Paraview collection (`.pvd`)