fftw_wavefunc.h

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/*
** fftw_wavefunc.h
** 
Copyright (C) 2009 Joseph Pingenot

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU Affero General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Affero General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

** Made by Johnny Q. Hacker
** Login   <solarion@nathan>
** 
** Started on  Mon Nov 16 06:35:01 2009 Johnny Q. Hacker
** Last update Mon Nov 16 06:35:01 2009 Johnny Q. Hacker
*/

#include <libpostproc/lp_wavefunction.h>
#include <libpostproc/density_1d.h>

#ifndef     FFTW_WAVEFUNC_H_
# define    FFTW_WAVEFUNC_H_

#ifdef __cplusplus
extern "C" {
#endif

  /**returns the electrostatic potential for a charge distribution rho and epsilon distribution epsilon.
     *\param rho a struct density containing the charge density. This should be in Coulombs per meter (the meter square would otherwise be multiplied internally; this increases accuracy to just do one division
     *\param epsilon a struct density containing the electrostatic constant for the materials across the structure (\epsilon*\epsilon_0)
     *\param rhoprime_out pointer to a pointer to a struct density to store rho divided by epsilon at each point.
     *\param dielectric_term_k: density which contains the *pre-fourier-transformed* inhomogeneous dielectric term (del ln(epsilon) . del phi) With this argument, this can be used for a step of an iterative or recursive approach.
     *\param dielectric_term_r: density which contains the realspace inhomogeneous dielectric term (del ln(epsilon) . del phi) With this argument, this can be used for a step of an iterative or recursive approach.
     *\return a struct density containing the electrostatic potential distribution.
     *\note the final result of the equation will be multiplied by -1; therefore, rho and the dielectric term will be *added* together internally.
     *\note RHO MUST BE IN UNITS OF COULOMBS PER METER. This is usually done by taking a pre-normalized wavefunction (i.e. wavefunction such that the sum at all of the points is 1) and dividing it by the length of a single side of a (cubic!) grid cell.  Accepting inputs in C/m instead of C/m^3 has improved accuracy, since the m^3 in the demoninator would otherwise be (approximately; this is finite-precision math!) divided out when multiplying by delta^2 (using the notation in Numerical Recipes 3rd Ed, p. 1054)
     *\note epsilon should be in units of F/m.  This is conventional.
     *\note dielectric_term_k and dielectric_term_r are complementary.  It is not checked, however.  The unused parameter should be set to NULL.
     */
  struct density* get_potential_for_density(const struct density* rho, const struct density* epsilon, struct density** rhoprime_out, const struct density* dielectric_term_k, const struct density* dielectric_term_r, GError **e);

  /**Solve the Poisson equation for an inhomogeneous dielectric using a multigrid method described in January 2011
   *\param rho charge dnesity in C/m (see comments on get_potential_for_density
   *\param epsilon dielectric constant as a function of position
   *\param close_enough convergence check (max abs percent change must be less than this value)
   *\param e pointer to a pointer to a GError to return error information.
   */
  struct density* get_potential_for_density_inhomog_multigrid(const struct density* rho, const struct density* epsilon, double close_enough, GError **e);

  /**Solve the Poisson equation for an inhomogeneous dielectric using simple symmetric finite differencing
   *\param rho charge dnesity in C/m (see comments on get_potential_for_density
   *\param epsilon dielectric constant as a function of position
   *\param close_enough convergence check (max abs percent change must be less than this value)
   *\param global use maximum abs value of d1 instead of the local value of d1 for finding percent difference between iterations
   *\param save_iterations save del_phi (z slices and grid dump) and phi (z slices) data from each iteration.
   *\param e pointer to a pointer to a GError to return error information.
   */
  struct density* get_potential_for_density_inhomog_simple(const struct density* rho, const struct density* epsilon, double close_enough, int global, int save_iterations, GError **e);

  struct density_1d* get_potential_for_density_1d(const struct density_1d* rho, const struct density_1d* epsilon, struct density_1d** rhoprime_out, GError **e);


#ifdef __cplusplus
}
#endif

#endif      /* !FFTW_WAVEFUNC_H_ */