PoissonSolver

PoissonSolver

Section Hamiltonian::Poisson
Type integer

Defines which method to use to solve the Poisson equation. Some incompatibilities apply depending on dimensionality, periodicity, etc. For a comparison of the accuracy and performance of the methods in Octopus, see P Garcia-Risueño, J Alberdi-Rodriguez et al., J. Comp. Chem. 35, 427-444 (2014) or arXiV. Defaults:
1D and 2D: fft.
3D: cg_corrected if curvilinear, isf if not periodic, fft if periodic.
Dressed orbitals: direct_sum.

Options:

• NoPoisson:
  Do not use a Poisson solver at all.
  
• direct_sum:
  Direct evaluation of the Hartree potential (only for finite systems).
  
• fft:
  The Poisson equation is solved using FFTs. A cutoff technique for the Poisson kernel is selected so the proper boundary conditions are imposed according to the periodicity of the system. This can be overridden by the PoissonFFTKernel variable. To choose the FFT library use FFTLibrary
  
• cg:
  Conjugate gradients (only for finite systems).
  
• cg_corrected:
  Conjugate gradients, corrected for boundary conditions (only for finite systems).
  
• multigrid:
  Multigrid method (only for finite systems).
  
• isf:
  Interpolating Scaling Functions Poisson solver (only for finite systems).
  
• psolver:
  Solver based on Interpolating Scaling Functions as implemented in the PSolver library. Parallelization in k-points requires PoissonSolverPSolverParallelData = no. Requires the PSolver external library.
  

 call parse_variable(namespace, 'PoissonSolver', default_solver, this%method)