Generating a square mesh

I have found a book that teaches the solution of PDEs and plots the results.

I want to change the plot to a square mesh instead of traingular mesh.

This the code they use:

tri = delaunay(x,y);

trisurf(tri,x,y,u_fem);

which generates something like this:

How do I make sure that the mesh generated does not have those diagonal lines between the squares? and then plot that?

*using MATLAB online

Let me know if the entire code is needed, its in multiple bunches

Thanks

[Bruno Luong]

Finite Elements methods (FEM) must work on triangular mesh, so it must have those diagonals to form set of triangles.

This piece of code show exactly the mesh as it is. This is a good visualization.

Answer 1

[Askic V]

If you look at the examples in the Matlab documentation for the mesh function, you can find something like this:

[X,Y] = meshgrid(-5:.5:5);
Z = Y.*sin(X) - X.*cos(Y);
s = mesh(X,Y,Z,'FaceAlpha','0.5');

As you can see this division is not triangular nor does it have diagonals.

[Saim Ehtesham]

when I am plotting it on a few different functions, I see a horizontal green line mesh at x and y =0 other than the curved lines, how can I fix that?