[crg123]

Hello,

I am solving a 2D hyperbolic PDE, which gives me a solution in 'x' and 'y' direction for each node on the mesh, for each time step. Therefore, if I freeze the time step, I have a solution vector in 'x', and 'y', for the whole mesh, i.e., a single value in both 'x' and 'y' direction, for each node on mesh.

It looks like this when the solution is initially viewed in Paraview.



You can notice the 'x' and 'y' solution for all points (nodes). The no. of rows is the total no. of nodes on mesh.

Then, I convert this vtk file to .csv, and import it to MATLAB, where I run some post processing on the 'x' and 'y' solution vectors. Now, I have replaced the originally imported solution vectors 'x' and 'y', with some new values. I wanted to take back these new solutions to Paraview again for plotting. So I used a tool called vtktrisurf in MATLAB. The problem was that this tool only takes 1 solution vector, i.e., I can either give the 'x' solution vector or 'y'. So, I used pythagoras theorem on respective elements of 'x' and 'y' solutions, to generate a single vector. The vtk was created, and the simulation in PARAVIEW was exactly what I was hoping to see. However, when I use pythagoras theorem, I convert all negative components of the solution to positive. It will show me what I want to see when there is no scalar warping. However, when I warp it with scalar in Paraview, it shows the entire profile in positive values. That is not actually true, because there were negative values in the solution. Long story short, how can I view the correct simulation. Maybe the answer goes back to the point where I convert my matrix in MATLAB to vtk. I also have the option of creating a separate vtk for 'x' solution and separate for 'y'. In that case, is there a way to superpose them in Paraview to view the correct profile?

Thanks a lot for your time!