Outputs and Postprocessing

This page explains the file outputs that elfe3D_GPR writes and the tools available for postprocessing.

Solver Outputs

The solver writes electric and magnetic field results to the configured output files. These are typically stored in:

  • out_<experiment_name>/electric_fields*

  • out_<experiment_name>/magnetic_fields*

For elfe3D_GPR, the output files contain columns with frequency, receiver coordinates and the field components for the recorded receiver lines. The text output files are commonly grouped in two ways:

  • per frequency, using files of names with *_receiver_line appended to the base name,

  • per receiver location, using files with the base names.

Ordering is always by increasing receiver number.

The file headers in the electric and magnetic field text files are as follows:

frequency coordinate_x coordinate_y coordinate_z  Ex_real Ex_imaginary  Ey_real Ey_imaginary  Ez_real Ez_imaginary

frequency coordinate_x coordinate_y coordinate_z  Hx_real Hx_imaginary  Hy_real Hy_imaginary  Hz_real Hz_imaginary

The elfe3D_GPR Python I/O module also writes .vtk field distributions for visualization. These .vtk files capture the computed electromagnetic field component over the mesh volume and can be opened in tools like ParaView or other VTK-compatible viewers. In the current workflow, .vtk files are usually generated during refinement or output if output_fields_vtk is enabled, and they typically store field data for the first frequency only.

Python Module Visualization

The repository includes helper modules in io/outputs for reading, processing, and visualizing results:

  • io.outputs.fieldreader: loaders for solver output and analytical reference data in different formats.

  • io.outputs.visualize: plotting classes for receiver-line comparison and error analysis

  • io.outputs.postprocess: additional processing utilities for field comparisons and statistics

These modules are intended to support notebook-based analysis of solver output.

Common output tools used in the example notebooks

The example notebooks demonstrate the most common output workflow for elfe3D_GPR:

  • AnalyticalLoader loads semi-analytical reference solutions from CSV files.

  • ElfeLoader reads solver-generated receiver-line output, especially electric_fields_receiver_line.txt.

  • ReceiverLinePlot compares multiple datasets on a 2x2 grid of amplitude, phase, real, and imaginary components.

  • ReceiverLineErrorPlot plots normalized errors relative to a reference dataset in a 2x2 layout.

  • ReceiverLineCombined shows one numerical dataset together with an analytical reference on the top row and the corresponding errors on the bottom row.

  • ErrorHistogramPlot shows amplitude and phase error distributions for one or more datasets.

These tools are used throughout the notebooks, including examples/01_homogeneous_free-space.ipynb, examples/02_homogeneous_earth.ipynb, examples/03_two_layered_earth.ipynb, and so on.