Postprocessing and Visualization

As described in the section Problem Types, each simulation type writes relevant postprocessed scalar quantities to disk in the directory specified by config["Problem"]["Output"], including but not limited to computed values like eigenfrequencies, scattering parameters, or lumped element parameters. In addition, each simulation type will write a file called domain-E.csv, which includes information about the electric and magnetic field energies, as well as lumped element energies, for each step of the simulation (eigenmode, frequency, or time step, for examples).

The participation ratios for bulk dielectrics and interface dielectric layers can be computed for simulations involving the electric field. For model boundaries, the integrated surface charge or magnetic flux can also be postprocessed. These features are described in Domain postprocessing and in Boundary postprocessing.

Additionally, the computed fields can be automatically probed for their vector values at one or more points in space. This probe functionality is also described in Domain postprocessing.

Finally, as described further in Visualization, various field quantities on the 3D computational domain as well as 2D domain boundaries and material interfaces are written to disk when requested using the relevant parameters under config["Solver"]. These fields are meant to be visualized with ParaView.

Domain postprocessing

Domain postprocessing capabilities are enabled by including objects under config["Domains"]["Postprocessing"] in the configuration file. These include:

config["Domains"]["Postprocessing"]["Dielectric"] : Postprocessess bulk dielectric loss based on the participation ratio of the electric field in a lossy region. The respective participation ratios and quality factors for each domain (associated with the specified domain attributes and indexed by the specified integer "Index") are computed using the material properties provided and are written to domain-Q.csv in the specified postprocessing output directory.
config["Domains"]["Postprocessing"]["Probe"] : Probe the values of the computed electric field and magnetic flux density solutions at specified locations in the computational domain. The availability of the $\bm{E}$ and $\bm{B}$ fields depends on the problem type (for example, for magnetostatic problems, only $\bm{B}$ is output and $\bm{E}$ is not computed, whereas the inverse is true for electrostatics). For each computed field, the postprocessed values are written to probe-E.csv and probe-B.csv in the specified output directory.

Boundary postprocessing

Boundary postprocessing capabilities are enabled by including objects under config["Boundaries"]["Postprocessing"] in the configuration file. These include:

config["Boundaries"]["Postprocessing"]["Capacitance"] : Postprocess the integral of the surface charge on a surface defined by a list of boundary attributes, and divide by the excitation voltage to get the capacitive coupling. The resulting capcitances are written to surface-C.csv in the specified output directory.
config["Boundaries"]["Postprocessing"]["Inductance"] : Postprocess the magnetic flux through a surface defined by a list of boundary attributes, and divide by the excitation current to the inductive coupling. The resulting inductances are written to surface-M.csv in the specified output directory.
config["Boundaries"]["Postprocessing"]["Dielectric"] : Postprocesses interface dielectric loss at surfaces of the model by specifying the interface thickness, permittivity, and loss tangent. See https://arxiv.org/pdf/1509.01854.pdf or https://aip.scitation.org/doi/10.1063/1.3637047 for more information. The participation ratios and associated quality factors are written to the file surface-Q.csv in the specified output directory.

Visualization

When specified in the configuration file, the electric field and magnetic flux density solutions are written to disk for 3D visualization with ParaView. Various other postprocessed fields are also written to the ParaView database as available, including electric and magnetic energy density, surface currents, and charge density. These files are found in the paraview/ directory located in the output directory specified under config["Problem"]["Output"].

In addition to the full 3D fields, a ParaView data collection for the boundary mesh is also written to disk. The boundary mesh includes all surfaces with prescribed boundary conditions as well as any material interfaces in the computational domain.