pdegrad (Partial Differential Equations Toolbox)

The gradient of a PDE solution.

[ux,uy]=pdegrad(p,t,u) 
[ux,uy]=pdegrad(p,t,u,sdl)

[ux,uy]=pdegrad(p,t,u)

returns the gradient of u evaluated at the center of each triangle.

Row i from 1 to N of ux contains

row i from 1 to N of uy contains

There is one column for each triangle in t in both ux and uy.

The geometry of the PDE problem is given by the mesh data p and t. Details on the mesh data representation can be found in the entry on initmesh.

The format for the solution vector u is described in assempde.

The optional argument sdl restricts the computation to the subdomains in the list sdl.