Initializes basic data structures of a Trigonometric Transform.
Checks consistency and correctness of user's data as well as initializes certain data structures required to perform the Trigonometric Transform.
Computes the forward Trigonometric Transform of type specified by the parameter.
Computes the backward Trigonometric Transform of type specified by the parameter.
Cleans the memory allocated for the data structure used by the FFT interface.
Poisson Solver routines enable approximate solving of certain two-dimensional and three-dimensional problems. Figure "Structure of the Poisson Solver" shows the general structure of the Poisson Solver.
This description always shows the solution process for the Helmholtz problem, because Fast Poisson Solvers and Fast Laplace Solvers are special cases of Fast Helmholtz Solvers (see Poisson Solver Implementation).