TO VISUALIZE IN MATLAB, YOU HAVE TO UPDATE
mesh.hh AND mesh.cc
AND FOLLOW THE INSTRUCTIONS BELOW

ADD THE FOLLOWING LINES TO mesh.hh (e.g. after refineUniform):

  /**
   * matlab output
   * write mesh (and solution data) and two plot commands into a matlab-file
   */
  void matlabOutput (const char* filename, const Vector& solution=Vector()) const;
  


ADD THE FOLLOWING LINES TO mesh.cc:



void Mesh :: matlabOutput (const char* filename, const Vector& solution) const
{
  ofstream ofs (filename);

  ofs << "p = [[" << verts[0][0] << "; " << verts[0][1] << "]";
  for (int i=1; i<nVerts; ++i)
    ofs << ", [" <<  verts[i][0] << "; " << verts[i][1] << "]";
  ofs << "];" << endl;
  ofs << endl;

  if (nSegments == 0)
    {
      ofs << "e = []" << endl;
    }
  else
    {
      ofs << "e = [[" << segments[0][0]+1 << "; " << segments[0][1]+1 << "]";
      for (int i=1; i<nSegments; ++i)
        ofs << ", [" << segments[i][0]+1 << "; " << segments[i][1]+1 << "]";
      ofs << "];" << endl;
      ofs << endl;
    }
  
  ofs << "t = [[" << trigs[0][0]+1 << "; " << trigs[0][1]+1 << "; " << trigs[0][2]+1 << "; 1]";
  for (int i=1; i<nTrigs; ++i)
    ofs << ", [" << trigs[i][0]+1 << "; " << trigs[i][1]+1 << "; " << trigs[i][2]+1 << "; 1]";
  ofs << "];" << endl;
  ofs << endl;
  
  if (solution.size() != nVerts)
    {
      ofs << "pdemesh (p, e, t);" << endl << endl;
    }
  else
    {
      ofs << "u = [" << solution[0];
      for (int i=1; i<nVerts; ++i)
        ofs << ", " << solution[i];
      ofs << "];" << endl;
      ofs << endl;
      
      ofs << "pdemesh (p, e, t, u);" << endl << endl;

      ofs << "pdesurf (p, t, transpose(u));" << endl << endl;
    }
  
} // Mesh :: matlabOutput



IN YOUR MAIN PROGRAM, ADD

mesh.matlabOutput ("output.m", u);

AFTER YOU HAVE COMPUTED THE SOLUTION u.
RUN YOUR PROGRAM.
THEN, START MATLAB, OPEN THE FILE output.m
COMMENT OUT ONE OF THE LAST TWO LINES
(pdemesh will visualize the edges of the mesh and the solution,
whereas pdesurf will visualize the solution colored)
AND CHOOSE "cell -> evaluate entire file" FROM THE MENU.