Interpolate from node data to triangle midpoint data
ut = pdeintrp(p,t,un)
The geometry of the PDE problem is given by the mesh data p and t. For details on the mesh data representation, see initmesh.
Let N be the dimension of the PDE system, np the number of node points, and nt the number of triangles. The components of the node data are stored in un either as N columns of length np or as an ordinary solution vector. The first np values of un describe the first component, the following np values of un describe the second component, and so on. The components of triangle data are stored in ut as N rows of length nt.
pdeprtni and pdeintrp are not inverse functions. The interpolation introduces some averaging.