DATAGRID Generates points of an N-D grid with specified limits
u = datagrid(limits,Npoints)
limits: (Rx2) matrix with the following structure
[low_limit_1, high_limit_1;
low_limit_2, high_limit_2;
... , ... ;
low_limit_R, high_limit_R]
Npoints: (optional) A vector specifying the number
of points in the grid for each dimension. A scalar can be
used specifying a single value for all dimensions.
If not specified, a suitable value is chosen.