# PL Routines for the Cartesian Solver

The section gives detailed description of Cartesian PL routines, their syntax, parameters and values they return. All flavors of the same routine, namely, double-precision and single-precision, 2D and 3D, are described together.

### Note

Some of the routine parameters are used only in the 3D Fast Helmholtz Solver.

PL routines call the Intel MKL FFT interface (described in FFT Functions), which enhances performance of the routines.

- ?_init_Helmholtz_2D/?_init_Helmholtz_3D
  Initializes basic data structures of the Fast 2D/3D Helmholtz Solver.
- ?_commit_Helmholtz_2D/?_commit_Helmholtz_3D
  Checks consistency and correctness of user's data as well as initializes certain data structures required to solve 2D/3D Helmholtz problem.
- ?_Helmholtz_2D/?_Helmholtz_3D
  Computes the solution of 2D/3D Helmholtz problem specified by the parameters.
- free_Helmholtz_2D/free_Helmholtz_3D
  Cleans the memory allocated for the data structures used by the FFT interface.

Parent topic: Poisson Library Routines