[Users] New, accurate integration method in Multipole

[Erik Schnetter]

I just committed a new, accurate integration method "Driscoll&Healy"
in thorn EinsteinAnalysis/Multipole. This method is described in J.R.
Driscoll and D.M. Healy Jr., Computing Fourier transforms and
convolutions on the 2-sphere, Advances in Applied Mathematics,
15(2):202–250, 1994. This method uses the interpolated values on the
sphere to define a spectral reconstruction of the function on the
sphere, and integrates this function, yielding essentially exponential
convergence.

Of course, accuracy in a production simulation will still be limited
by the accuracy of the interpolation onto the sphere, as well as the
accuracy of the time evolution itself.

-erik

-- 
Erik Schnetter <schnetter at cct.lsu.edu>
http://www.perimeterinstitute.ca/personal/eschnetter/