Hints for Problem #4 - Connection Matrices

[MATLAB logo] Exploiting MATLAB's Data Structures

The function tri = delaunay(x,y) produces the Delaunay triangulation for the points (x,y), taken element-wise. The matrix tri is M-by-3 and each row contains the indices of the points that make up a given triangle. For instance x(tri(2,:)) are the x-coordinates of the points that make of the second triangle.
The function trisurf(tri,x,y,z) produces a triangular surface plot from the Delaunay triangulation, the data points (x,y) and the height of the surface z.
The function s = sparse(I,J,V) produces a sparse matrix that contains values at the element with indices I(k),J(k). The value at for that element is set to V(k). If any of the values in I,J overlap they are added together to produce the final result. This "summing" property of sparse can be quite handy at times (make a mental note of it).