Solution Store for dG set up

General Discussion
1

For discontinuous space set up how to store the solution with x and y values in a text file?
I tried

{
ofstream ff(“phi.txt”);
ff << phi ;
}
savemesh(Th,“Th.msh”);

and

{
ofstream ff(“graph.txt”);
for (int i = 0; i < Th.nt; i++)
{
for (int j = 0; j < 3; j++)
ff << Th[i][j].x << " "<< Th[i][j].y << " " << phi[Vh(i,j)] << endl;
ff << Th[i][0].x << " " << Th[i][0].y << " " << phi[Vh(i,0)] << “\n\n\n”
}
}

But it did not work.

2

Your syntax is correct for P1dc fespace Vh(Th,P1dc).
Your first try stores the coordinates in the basis of the fespace.
It can be used for loading later in FF++.
Your second try solves the location of dof and the value of the function.
You simply miss {} for the content of the j loop:

{
ofstream ff("graph.txt");
for (int i = 0; i < Th.nt; i++)
{
for (int j = 0; j < 3; j++){
ff << Th[i][j].x << " "<< Th[i][j].y << " " << phi[][Vh(i,j)] << endl;
}
}
}
3

Do I need to change anything for P2dc fespace Vh(Th, P2dc)?

4

for fespace Vh(Th,P2dc) you can do as

{
ofstream ff("graph.txt");
real[int] mix(3),miy(3);
for (int i = 0; i < Th.nt; i++)
{
mix(0)=(Th[i][1].x+Th[i][2].x)/2.;//coordinates of the middle of the edges
miy(0)=(Th[i][1].y+Th[i][2].y)/2.;
mix(1)=(Th[i][0].x+Th[i][2].x)/2.;
miy(1)=(Th[i][0].y+Th[i][2].y)/2.;
mix(2)=(Th[i][0].x+Th[i][1].x)/2.;
miy(2)=(Th[i][0].y+Th[i][1].y)/2.;
for (int j = 0; j < 3; j++){
ff << Th[i][j].x << " "<< Th[i][j].y << " " << phi[][Vh(i,j)] << endl;
ff << mix(j) << " "<< miy(j) << " " << phi[][Vh(i,j+3)] << endl;
}
}
}