Hello guys. I have this question when I am trying to solve poisson equation in matlab. Why use triangular mesh when solving poisson equation in pde toolbox? e.g. poisolv And how do I convert my data in rectangular mesh to triangular mesh? Because I only found the reverse, which is tri2grid(). The problem I have now is that I do not have a closed expression for the function on the right hand side. What I have is numerical, i.e. a matrix in rectangular mesh. How could I modify the fast poisson solver to satisfy my needs? Thanks!