Sets the global coordinates from -1 to 1 to the GLL points of as many GLL elements that fit the number of grid points
Collective on da
da - the
n - the number of GLL nodes
nodes - the GLL nodes
The parallel decomposition of grid points must correspond to the degree of the GLL. That is, the number of grid points
on each process much be divisible by the number of GLL elements needed per process. This depends on whether the
periodic or not.