Direct use of the Trigonometric Transform routines may be helpful to those
who have already implemented their own solvers similar to the
Math Kernel Library
Poisson Solver. As it may be hard enough to modify the
original code so as to make it work with Poisson Solver, you are encouraged to use fast
(staggered) sine/cosine transforms implemented in the Trigonometric Transform interface to
improve performance of your solver.
Both Trigonometric Transform and Poisson Solver routines can be called
from C and Fortran.