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Post-processing of Coefficients in VTK files #174
Description
Activity
Coefficient VTK post-processing (multigrains test)
In the new multigrains test in
tests/Studies/multigrains/test1_amr/main.cpp, a coefficient is
specially designed to be post-processed in VTK file.In addition to standard definition of Coefficient, the user must give a name for the
coefficientCoefficient swithchingFct(Glossary::PhaseField, Scheme::Implicit, SwitchingFunction()); swithchingFct.set_name("SWF");
and affect the coefficient to a Problem
pb.set_vtk_coefficients({swithchingFct});Coefficient VTK post-processing (multigrains test)
In the new multigrains test in
tests/Studies/multigrains/test1_amr/main.cpp, a coefficient is specially designed to be post-processed in VTK file.In addition to standard definition of Coefficient, the user must give a name for the coefficient.
Coefficient squares(Glossary::PhaseField, Scheme::Implicit, SumOfSquares()); squares.set_name("Squares");
and affect the coefficient to a Problem
pb.set_vtk_coefficients({squares});In this example, the JSON file is given by
{ "expression":"y*y+Sum(x[i]*x[i], (i,1,29))", "variables":"y", "auxiliary_variables":"x(1..29)", "class_name":"SumOfSquares", "outputfile":"GrainsCoefficients" }As the multiphase-field problem is solved using a partitioned algorithm, we define one primary variable (
y) and the other as auxiliary variables.This new feature is compatible with unified and non-unified VTK post-processing.
- linked a pull request that will close this issueSimplify multiphase test setup + add Coefficient VTK post-processing #176
on Sep 11, 2026
Goal
Add support for post-processing
Coefficientobjects (not justVariables) into VTK output,alongside the existing field save mechanism.
What's needed
Coefficientonto a grid function (viaMfemCoefficient) at save time, usingthe current variable values and auxiliary variables.
DataCollectionso they appear in Paraview outputlike any other field.
Scope
PostProcessing::save_coefficientsProblemBase::collect_vtk_coefficientsCoupling::collect_vtk_coefficientsTimeDiscretization::save_vtk_unifiedMfemCoefficient::Eval