message: Editing header
diff: // angular frequency omega, imposed at the boundary or a portion
  // of the boundary.
  //
  -// simple finite element discretization of the Laplace problem
  -// -Delta u = 1 with homogeneous Dirichlet boundary conditions.
  -// Specifically, we discretize using a FE space of the specified
  -// order, or if order < 1 using an isoparametric/isogeometric
  -// space (i.e. quadratic for quadratic curvilinear mesh, NURBS for
  -// NURBS mesh, etc.)
  +// In electromagnetics the coefficients are typically named
  +// the permeability, mu = 1/a, permittivity, epsilon = b, and
  +// conductivity, sigma = c. The user can specify these constants
  +// using either set of names.
  //
  -// The example highlights the use of mesh refinement, finite
  -// element grid functions, as well as linear and bilinear forms
  -// corresponding to the left-hand side and right-hand side of the
  -// discrete linear system. We also cover the explicit elimination
  -// of essential boundary conditions and the optional connection
  -// to the GLVis tool for visualization.
  -
  #include "mfem.hpp"
  #include <fstream>
  #include <iostream>
  @@ -82,6 +73,7 @@ int main(int argc, char *argv[])
  int order = 1;
  int prob = 0;
  double freq = -1.0;
  + double a_coef = 0.0;
  bool visualization = 1;
  bool herm_conv = true;
  bool exact_sol = true;
  @@ -98,6 +90,12 @@ int main(int argc, char *argv[])
  args.AddOption(&prob, "-p", "--problem-type",
  "Choose from 0: H_1, 1: H(Curl), or 2: H(Div) "
  "damped harmonic oscillator.");
  + args.AddOption(&a_coef, "-a", "--stiffness-coef",
  + "Stiffness coefficient (spring constant or 1/mu).");
  + args.AddOption(&epsilon_, "-b", "--mass-coef",
  + "Mass coefficient (or epsilon).");
  + args.AddOption(&sigma_, "-c", "--damping-coef",
  + "Damping coefficient (or sigma).");
  args.AddOption(&mu_, "-mu", "--permeability",
  "Permeability of free space (or 1/(spring constant)).");
  args.AddOption(&epsilon_, "-eps", "--permittivity",
  @@ -126,6 +124,10 @@ int main(int argc, char *argv[])
  args.PrintOptions(cout);
  }
  + if ( a_coef != 0.0 )
  + {
  + mu_ = 1.0 / a_coef;
  + }
  if ( freq > 0.0 )
  {
  omega_ = 2.0 * M_PI * freq;
  